Cirrus Logic CS5480 User Manual

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CS5480

VDDA

GNDA

TX / SDO

RX / SDI

UART/SPI

Serial

Interfac e

Energy

Pulse

Conversion

RESET

Calculation

4th Order 

Modulator

Digital

Filter

HPF

Optio n

DO1

DO2

Digital

Filter

4th Order 

Modulator

HPF

Optio n

Temperature

Sensor

VREF+

Voltage

Reference

VDDD

VREF-

System

Clock

IIN2 +

IIN2 -

PGA

IIN1+

IIN1-

PGA

10x

CS5480

GNDD

SCLK

SSEL

DO3

VIN+

VIN-

Clock

Generator

XIN XOUT

MODE

Digital

Filter

HPF

Optio n

4th Order 

Modulator

Three Channel Energy Measurement IC

Features

• Superior Analog Performance with Ultra-low Noise Level & High SNR

• Energy Measurement Accuracy of 0.1% over 4000:1 Dynamic Range

• Current RMS Measurement Accuracy of 0.1% over 1000:1 Dynamic Range

• 3 Independent 24-bit, 4 for Voltage and Current Measurements

• 3 Configurable Digital Outputs for Energy Pulses, Zero-crossing, or Energy Direction

• Supports Shunt Resistor, CT, & Rogowski Coil Current Sensors

• On-chip Measurements & Calculations:

- Active, Reactive, and Apparent Power

- RMS Voltage and Current

- Power Factor and Line Frequency

- Instantaneous Voltage, Current, and Power

• Overcurrent, Voltage Sag, and Voltage Swell Detection

• Ultra-fast On-chip Digital Calibration

• Internal Register Protection via Checksum and Write Protection

• UART/SPI™ Serial Interface

• On-chip Temperature Sensor

• On-chip Voltage Reference (25ppm / °C Typ.)

• Single 3.3V Power Supply

• Ultra-fine Phase Compensation

• Low Power Consumption: <13mW

• Power Supply Configurations GNDA = GNDD = 0V, VDDA = +3.3V

• 4mm x 4mm, 24-pin QFN Package

ORDERING INFORMATION

See Page 69.

-order, Delta-Sigma Modulators

Description

The CS5480 is a high-accuracy, three-channel, energy measurement analog front end.

The CS5480 incorporates independent, 4th order, Delta-Sigma analog-to-digital converters for every channel, reference circuitry, and the proven EXL signal processing core to provide active, reactive, and apparent energy measurement. In addition, RMS and power factor calculations are available. Calculations are output via configurable energy pulse, or direct UART/SPI™ serial access to on-chip registers.

Instantaneous current, voltage, and power measurements are also available over the serial port. Multiple serial options are offered to allow customer flexibility. The SPI provides higher speed, and the 2-wire UART minimizes the cost of isolation where required.

Three configurable digital outputs provide energy pulses, zerocrossing, energy direction, and interrupt functions. Interrupts can be generated for a variety of conditions including voltage sag or swell, overcurrent, and more. On-chip register integrity is assured via checksum and write protection. The CS5480 is designed to interface to a variety of voltage and current sensors including shunt resistors, current transformers, and Rogowski coils.

On-chip functionality makes digital calibration simple and ultra-fast, minimizing the time required at the end of the customer production line. Performance across temperature is ensured with an on-chip voltage reference with very low drift. A single 3.3V power supply is required, and power consumption is very low at <13mW. To minimize space requirements, the CS5480 is offered in a low-cost, 4mm x 4mm 24-pin QFN package.

Cirrus Logic, Inc.

http://www.cirrus.com

MAR’13

DS980F3

CS5480

TABLE OF CONTENTS

1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

2. Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

2.1 Analog Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

2.1.1 Voltage Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.1.2 Current1 and Current2 Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

2.1.3 Voltage Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.1.4 Crystal Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.2 Digital Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

2.2.1 Reset Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

2.2.2 Digital Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

2.2.3 UART/SPI™ Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.2.3.1 SPI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

2.2.3.2 UART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

2.2.4 MODE Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

3. Characteristics and Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

4. Signal Flow Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

4.1 Analog-to-Digital Converters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

4.2 Decimation Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

4.3 IIR Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

4.4 Phase Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

4.5 DC Offset and Gain Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

4.6 High-pass and Phase Matching Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

4.7 Digital Integrators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

4.8 Low-rate Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

4.8.1 Fixed Number of Samples Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.8.2 Line-cycle Synchronized Averaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.8.3 RMS Current and Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.8.4 Active Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

4.8.5 Reactive Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

4.8.6 Apparent Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.8.7 Peak Voltage and Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

4.8.8 Power Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.9 Average Active Power Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

4.10 Average Reactive Power Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

5. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

5.1 Power-on Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

5.2 Power Saving Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

5.3 Zero-crossing Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

5.4 Line Frequency Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

5.5 Meter Configuration Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

5.6 Tamper Detection and Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

5.6.1 Anti-tampering on Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

5.6.1.1 Automatic Channel Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

5.6.1.2 Manual Channel Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

5.6.2 Anti-tampering on Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

5.7 Energy Pulse Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

2 DS980F3

CS5480

5.7.1 Pulse Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5.7.2 Pulse Width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

5.8 Voltage Sag, Voltage Swell, and Overcurrent Detection . . . . . . . . . . . . . . . . . . . . .26

5.9 Phase Sequence Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

5.10 Temperature Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

5.11 Anti-Creep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

5.12 Register Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

5.12.1 Write Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

5.12.2 Register Checksum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

6. Host Commands and Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.1 Host Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.1.1 Memory Access Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.1.1.1 Page Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.1.1.2 Register Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.1.1.3 Register Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.1.2 Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.1.3 Checksum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

6.1.4 Serial Time Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

6.2 Hardware Registers Summary (Page 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

6.3 Software Registers Summary (Page 16) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.4 Software Registers Summary (Page 17) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

6.5 Software Registers Summary (Page 18) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6.6 Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

7. System Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7.1 Calibration in General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7.1.1 Offset Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7.1.1.1 DC Offset Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7.1.1.2 Current Channel AC Offset Calibration . . . . . . . . . . . . . . . . . . . . . . . 63

7.1.2 Gain Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

7.1.3 Calibration Order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

7.2 Phase Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

7.3 Temperature Sensor Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65

7.3.1 Temperature Offset and Gain Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8. Basic Application Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

9. Package Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

10. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69

11. Environmental, Manufacturing, and Handling Information . . . . . . . . . . . . . . . . . . . . . 69

12. Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

DS980F3 3

CS5480

LIST OF FIGURES

Figure 1. Oscillator Connections................................................................................................... 7

Figure 2. Multi-device UART Connections.................................................................................... 8

Figure 3. UART Serial Frame Format........................................................................................... 8

Figure 4. Active Energy Load Performance.................................................................................. 9

Figure 5. Reactive Energy Load Performance............................................................................ 10

Figure 6. IRMS Load Performance ............................................................................................. 10

Figure 7. SPI Data and Clock Timing ......................................................................................... 15

Figure 8. Multi-device UART Timing........................................................................................... 15

Figure 9. Signal Flow for V1, I1, P1, Q1 Measurements ............................................................ 17

Figure 10. Signal Flow for V2, I2, P2, and Q2 Measurements ................................................... 17

Figure 11. Low-rate Calculations ................................................................................................18

Figure 12. Power-on Reset Timing ............................................................................................. 21

Figure 13. Zero-crossing Level and Zero-crossing Output on DOx ............................................ 22

Figure 14. Channel Selection and Tamper Protection Flow ....................................................... 23

Figure 15. Automatic Channel Selection .................................................................................... 24

Figure 16. Energy Pulse Generation and Digital Output Control ................................................ 25

Figure 17. Sag, Swell, and Overcurrent Detect .......................................................................... 26

Figure 18. Phase Sequence A, B, C for Rising Edge Transition ................................................ 27

Figure 19. Phase Sequence C, B, A for Rising Edge Transition ................................................ 28

Figure 20. Byte Sequence for Page Select................................................................................. 29

Figure 21. Byte Sequence for Register Read ............................................................................. 29

Figure 22. Byte Sequence for Register Write ............................................................................. 29

Figure 23. Byte Sequence for Instructions.................................................................................. 29

Figure 24. Byte Sequence for Checksum ................................................................................... 30

Figure 25. Calibration Data Flow ................................................................................................63

Figure 26. T Register vs. Force Temp ........................................................................................ 65

Figure 27. Typical Single-phase 3-Wire Connection .................................................................. 66

Figure 28. Typical Single-phase 2-Wire Connection .................................................................. 67

LIST OF TABLES

Table 1. POR Thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 2. Meter Configuration Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Table 3. Command Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Table 4. Instruction Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4 DS980F3

CS5480

1. OVERVIEW

The CS5480 is a CMOS power measurement integrated circuit that uses three  analog-to-digital converters to measure line voltage, two currents and temperature. It calculates active, reactive, and apparent power as well as RMS voltage and current and peak voltage and current. It handles other system-related functions, such as energy pulse generation, voltage sag and swell, overcurrent and zero-crossing detection, and line frequency measurement.

The CS5480 is optimized to interface to current transformers, shunt resistors, or Rogowski coils for current measurement and to resistive dividers or voltage transformers for voltage measurement. Two full-scale ranges are provided on the current inputs to accommodate different types of current sensors. The CS5480’s three differential inputs have a common-mode input range from analog ground (GNDA) to the positive analog supply (VDDA).

An on-chip voltage reference (nominally 2.4 volts) is generated and provided at analog output, VREF±.

Three digital outputs (DO1, DO2, and DO3) provide a variety of output signals, and depending on the mode selected, energy pulses, zero-crossings, or other choices.

The CS5480 includes a UART/SPI™ serial host interface to an external microcontroller. The serial select (SSEL) pin is used to configure the serial port to be a SPI or UART. SPI signals include serial data input (SDI), serial data output (SDO), and serial clock (SCLK). UART signals include serial data input (RX) and serial data output (TX). A chip select (CS interface with the microcontroller.

) signal allows multiple CS5480s to share the same serial

DS980F3 5

2. PIN DESCRIPTION

11 12

2021222324

Top-Down (Through Package) View

24-Pin QFN Package

XOUT

VDDD

GNDD

MODE

SSEL

IIN2-

IIN2+

VREF-

VREF+

GNDA

XIN

RESET

IIN1-

IIN1+

VIN+

SCLK

RX/SDI

TX/SDO

DO2

DO1

Thermal Pad

VIN-

VDDA

DO3

CS5480

Clock Generator

Crystal In Crystal Out

1,24

XIN, XOUT — Connect to an external quartz crystal. Alternatively, an external clock can be supplied to the XIN pin to provide the system clock for the device.

Digital Pins and Serial Data I/O

Digital Outputs 13,14,15

Reset 2

Serial Data I/O 16,17

Serial Clock Input 18

Serial Mode Select 20

Chip Select 19

Operating Mode Select 21

DO1, DO2, DO3 — Configurable digital outputs for energy pulses, interrupt, tamper indication,

energy direction, and zero-crossings.

RESET — An active-low Schmitt-trigger input used to reset the chip.

TX/SDO, RX / SDI — UART /SPI serial data output/input.

SCLK — Serial clock for the SPI.

SSEL — Selects the type of the serial interface, UART or SPI™. Logic level one - UART

selected. Logic level zero - SPI selected.

CS — Chip select for the UART/SPI.

MODE — Connect to VDDA for proper operation.

Analog Inputs/Outputs

Voltage Input 5,6

Current Inputs 4,3,8,7

Voltage Reference 10,9

Power Supply Connections

Internal Digital Supply 23

Digital Ground 22

Positive Analog Supply 12

Analog Ground 11

Thermal Pad

VIN+, VIN- — Differential analog input for the voltage channel.

IIN1+, IIN1-, IIN2+, IIN2- — Differential analog inputs for the current channels.

VREF+, VREF- — The internal voltage reference. A 0.1 µF bypass capacitor is required

between these two pins.

VDDD — Decoupling pin for the internal 1.8V digital supply. A 0.1µF bypass capacitor is required between this pin and GNDD.

GNDD — Digital ground.

VDDA — The positive 3.3V analog supply.

GNDA — Analog ground.

No Electrical Connection.

6 DS980F3

2.1 Analog Pins

XIN XOUT

C1 = 22pF C2 = 22pF

Figure 1. Oscillator Connections

The CS5480 has a differential input (VIN) for voltage input and two differential inputsIIN1 IIN2) for current1 and current2 inputs. The CS5480 also has two voltage reference pins (VREF) between which a bypass capacitor should be placed.

2.1.1 Voltage Input

The output of the line voltage resistive divider or transformer is connected to the (VIN) input of the CS5480. The voltage channel is equipped with a 10x, fixed-gain amplifier. The full-scale signal level that can be applied to the voltage channel is ±250mV. If the input signal is a sine wave, the maximum RMS voltage is 250mVp/

70.7% of maximum peak voltage.

2.1.2 Current1 and Current2 Inputs

The output of the current-sensing shunt resistor, transformer, or Rogowski coil is connected to the IIN1 or IIN2 input pins of the CS5480. To accommodate different current-sensing elements, the current channel incorporates a programmable gain amplifier (PGA) with two selectable input gains, as described in Config0 register description section 6.6.1 Configuration 0

(Config0) – Page 0, Address 0 on page 37. There is a

10x gain setting and a 50x gain setting. The full-scale signal level for current channels is ±50 mV and ± 250 mV for 50x and 10x gain settings, respectively. If the input signal is a sine wave, the maximum RMS voltage is

35.35mV

70.7% of maximum peak voltage.

2.1.3 Voltage Reference

The CS5480 generates a stable voltage reference of

2.4V between the VREF pins. The reference system

also requires a filter capacitor of at least 0.1µF between the VREF pins.

The reference system is capable of providing a reference for the CS5480 but has limited ability to drive external circuitry. It is strongly recommended that nothing other than the required filter capacitor be connected to the VREF pins.

2.1.4 Crystal Oscillator

An external, 4.096 MHz quartz crystal can be connected to the XIN and XOUT pins, as shown in Figure 1. To reduce system cost, each pin is supplied with an on-chip load capacitor.

2  176.78 mV

or 176.78mV

RMS

, which is approximately

RMS

, which is approximately

RMS

CS5480

Alternatively, an external clock source can be connected to the XIN pin.

2.2 Digital Pins

2.2.1 Reset Input

The active-low RESET pin, when asserted for longer than 120µs, will halt all CS5480 operations and reset internal hardware registers and states. When de-asserted, an initialization sequence begins, setting default register values. To prevent erroneous noise-induced resets to the CS5480, an external pull-up resistor and a decoupling capacitor are necessary on the RESET

2.2.2 Digital Outputs

The CS5480 provides three configurable digital outputs (DO1-DO3). They can be configured to output energy pulses, interrupt, zero-crossings, or energy directions. Refer to the description of the Config1 register in section

6.6.2 Configuration 1 (Config1) – Page 0, Address 1 on

page 38 for more details.

2.2.3 UART/SPI™ Serial Interface

The CS5480 provides five pins—SSEL, RX/SDI, TX/SDO, CS a host microcontroller and the CS5480.

SSEL is an input that, when low, indicates to the CS5480 to use the SPI port as the serial interface to communicate with the host microcontroller. The SSEL pin has an internal weak pull-up. When the SSEL pin is left unconnected or pulled high externally, the UART port is used as the serial interface.

pin.

, and SCLK—for communication between

DS980F3 7

2.2.3.1 SPI

UART

MASTER

SLAVE 0

SLAVE 1

SLAVE N

CS RX TX

CS0

CS1

CSN

0 1 2 7IDLE STOP3 4 5 6START

DATA

IDLE

The CS5480 provides a Serial Peripheral Interface (SPI) that operates as a slave device in 4-wire mode and supports multiple slaves on the SPI bus. The 4-wire SPI includes CS

is the chip select input for the CS5480 SPI port. A

, SCLK, SDI, and SDO signals.

high logic level de-asserts it, tri-stating the SDO pin and clearing the SPI interface. A low logic level enables the SPI port. Although the CS

pin may be tied low for systems that do not require multiple SDO drivers, using the CS

signal is strongly recommended to achieve a

more reliable SPI communication.

SCLK is the serial clock input for the CS5480 SPI port. Serial data changes as a result of the falling edge of SCLK and is valid at the rising edge. The SCLK pin is a Schmitt-trigger input.

SDI is the serial data input to the CS5480.

SDO is the serial data output from the CS5480.

The CS5480 SPI transmits and receives data MSB first. Refer to Switching Characteristics on page 14 and

Figure 7 on page 15 for more detailed information of

SPI timing.

2.2.3.2 UART

The CS5480 device contains an asynchronous, full-duplex UART. The UART may be used in either standard 2-wire communication mode (RX/TX) for connecting a single device or 3-wire communication mode (RX/TX/CS When connecting a single CS5480 device, CS be held low to enable the UART. Multiple CS5480 devices can communicate to the same master UART in the 3-wire mode by pulling a slave CS data transmissions. Common RX and TX signals are provided to all the slave devices, and each slave device requires a separate CS communication to that slave. The multi-device UART mode connections are shown in Figure 2.

) for connecting multiple devices.

should

pin low during

signal for enabling

CS5480

Figure 2. Multi-device UART Connections

The multi-device UART mode timing diagram provides the timing requirements for the CS

8. Multi-device UART Timing on page15).

The CS5480 UART operates in 8-bit mode, which transmits a total of 10 bits per byte. Data is transmitted and received LSB first, with one start bit, eight data bits, and one stop bit.

Figure 3. UART Serial Frame Format

The baud rate is defined in the SerialCtrl register. After chip reset, the default baud rate is 600, if MCLK is

4.096MHz. The baud rate is based on the contents of bits BR[15:0] in the SerialCtrl register and is calculated as follows:

BR[15:0] = Baud Rate x (524288/MCLK)

Baud Rate = BR[15:0] /(524288 / MCLK)

The maximum baud rate is 512K if MCLK is 4.096 MHz.

control (see Figure

2.2.4 MODE Pin

The MODE pin must be tied to VDDA for normal operation. The MODE pin is used primarily for factory test procedures.

8 DS980F3

CS5480

-1

-0.5

0.5

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Percent Error (%)

Current Dynamic Range (x : 1

)

Lagging PF = 0.5

Leading PF = 0.5

PF = 1

Figure 4. Active Energy Load Performance

3. CHARACTERISTICS AND SPECIFICATIONS

RECOMMENDED OPERATING CONDITIONS

Parameter Symbol Min Typ Max Unit

Positive Analog Power Supply VDDA 3.0 3.3 3.6 V Specified Temperature Range T

POWER MEASUREMENT CHARACTERISTICS

Parameter Symbol Min Typ Max Unit

Active Energy

(Note 1 and 2) Current Channel Input Signal Dynamic Range 4000:1

Reactive Energy

(Note 1 and 2) Current Channel Input Signal Dynamic Range 4000:1

Apparent Power

(Note 1 and 3) Current Channel Input Signal Dynamic Range 1000:1

Current RMS

(Note 1, 3, and 4) Current Channel Input Signal Dynamic Range 1000:1

Voltage RMS

(Note 1 and 3) Voltage Channel Input Signal Dynamic Range 20:1

Power Factor All Gain Ranges

(Note 1 and 3) Current Channel Input Signal Dynamic Range 1000:1

All Gain Ranges

Avg

S-±0.1-%

RMS

PF - ±0.1 - %

-40 - +85 °C

-±0.1- %

Notes: 1. Specifications guaranteed by design and characterization.

2. Active energy is tested with power factor (PF) = 1.0. Reactive energy is tested with Sin( level using a single energy pulse. Where: 1) One energy pulse = 0.5Wh or 0.5Varh; 2) VDDA = +3.3V, T

4.096MHz; 3) System is calibrated.

3. Calculated using register values; N

error calculated using register values. 1) VDDA = +3.3V; TA = 25°C; MCLK = 4.096MHz; 2) AC offset calibration applied.

4. I

RMS

≥4000.

) = 1.0. Energy error measured at system

= 25°C, MCLK =

TYPICAL LOAD PERFORMANCE

• Energy error measured at system level using single energy pulse; where one energy pulse = 0.5Wh or 0.5Varh.

•I

error calculated using register values.

RMS

• VDDA = +3.3V; T

= 25°C; MCLK = 4.096MHz.

DS980F3 9

CS5480

-1

-0.5

0.5

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Percent Error (%)

Current Dynamic Range (x : 1

)

Lagging sin() = 0.5

Leading sin() = 0.5

sin() = 1

Figure 5. Reactive Energy Load Performance

-1

-0.5

0.5

0 500 1000 1500

Percent Error (%)

Current Dynamic range (x : 1)

IRMS Error

Error

Figure 6. I

RMS

Load Performance

RMS

10 DS980F3

CS5480

ANALOG CHARACTERISTICS

• Min / Max characteristics and specifications are guaranteed over all Recommended Operating Conditions.

• Typical characteristics and specifications are measured at nominal supply voltages and T

• VDDA = +3.3V ±10%; GNDA = GNDD = 0V. All voltages with respect to 0 V.

• MCLK = 4.096MHz.

Parameter Symbol Min Typ Max Unit

Analog Inputs (Current Channels)

Common Mode Rejection

(DC, 50, 60Hz) CMRR 80 - - dB

Common Mode+Signal -0.25 - VDDA V

Differential Full-scale Input Range

[(IIN+) – (IIN-)] (Gain = 50)

(Gain = 10)

IIN

Total Harmonic Distortion (Gain = 50) THD 90 100 - dB

Signal-to-Noise Ratio (SNR)

Crosstalk from Voltage Inputs at Full Scale

Crosstalk from Current Input at Full Scale

(Gain = 10)

(Gain = 50)

(50, 60Hz) --115-dB

SNR

Input Capacitance IC - 27 - pF Effective Input Impedance EII 30 - - k

Offset Drift (Without the High-pass Filter) OD - 4.0 - µV/°C

Noise (Referred to Input)

(Gain = 10) (Gain = 50)

Power Supply Rejection Ratio (60Hz)

(Note 7) (Gain = 10)

(Gain = 50)

PSRR 60

Analog Inputs (Voltage Channels)

Common Mode Rejection

(DC, 50, 60Hz) CMRR 80 - - dB

Common Mode+Signal -0.25 - VDDA V

Differential Full-scale Input Range

[(VIN+) – (VIN-)] VIN - 250 - mV

Total Harmonic Distortion THD 80 88 - dB

Signal-to-Noise Ratio (SNR) SNR - 73 - dB

Crosstalk from Current Inputs at Full Scale

(50, 60Hz) --115-dB

Input Capacitance IC - 2.0 - pF Effective Input Impedance EII 2 - - M

Noise (Referred to Input) N

-40-µV

Offset Drift (Without the High-pass Filter) OD - 16.0 - µV/°C

Power Supply Rejection Ratio

(Note 7) (Gain = 10x)

(60Hz)

PSRR

60 65 - dB

Temperature

Temperature Accuracy

(Note 6) T-±5-°C

= 25°C.

250

80 80

3.5

65 75

µV µV

mV mV

dB dB

RMS

dB dB

RMS

DS980F3 11

Parameter Symbol Min Typ Max Unit

PSRR 20

150

-----------

log=

VREF

MAX

VREF

MIN

–

VREF

AVG

------------------------------------------------------------





TAMAX TAMIN–

----------------------------------------------





1.0 10

=

Power Supplies

Power Supply Currents (Active State)

Power Consumption

(Note 5) Active State (VDDA = +3.3 V)

Notes: 5. All outputs unloaded. All inputs CMOS level.

6. Temperature accuracy measured after calibration is performed.

7. Measurement method for PSRR: VDDA = +3.3 V, a 150mV (zero-to-peak) (60Hz) sine wave is imposed onto the +3.3V DC supply voltage at the VDDA pin. The “+” and “-” input pins of both input channels are shorted to GNDA. The CS5480 is then commanded to continuous conversion acquisition mode, and digital output data is collected for the channel under test. The (zero-to-peak) value of the digital sinusoidal output signal is determined, and this value is converted into the (zero-to-peak) value of the sinusoidal voltage (measured in mV) that would need to be applied at the channel’s inputs in order to cause the same digital sinusoidal output. This voltage is then defined as V

(VDDA = +3.3V) PSCA - 3.9 - mA

A+

Stand-by State

PSRR is (in dB):

VOLTAGE REFERENCE

Parameter Symbol Min Typ Max Unit

PC -

CS5480

12.9

4.5

mW mW

Reference

(Note 8)

Output Voltage VREF +2.3 +2.4 +2.5 V

Temperature Coefficient

Load Regulation

Notes: 8. It is strongly recommended that no connection other than the required filter capacitor be made to VREF±.

9. The voltage at VREF± is measured across the temperature range. From these measurements the following formula is used to calculate the VREF temperature coefficient:

10. Specified at maximum recommended output of 1µA sourcing. VREF is a sensitive signal; the output of the VREF circuit has a high output impedance so that the 0.1µF reference capacitor provides attenuation even to low-frequency noise, such as 50 Hz noise on the VREF output. Therefore VREF is intended for the CS5480 only and should not be connected to any external circuitry. The output impedance is sufficiently high that standard digital multimeters can significantly load this voltage. The accuracy of the metrology IC cannot be guaranteed when a multimeter or any component other than the 0.1µF capacitor is attached to VREF. If it is desired to measure VREF for any reason other than a very course indicator of VREF functionality, Cirrus recommends a very high input impedance multimeter such as the Keithley Model 2000 Digital Multimeter be used. Cirrus cannot guarantee the accuracy of the metrology with this meter connected to VREF.

(Note 9) TC

(Note 10) V

VREF

-25-ppm/°C

-30-mV

12 DS980F3

CS5480

DIGITAL CHARACTERISTICS

• Min / Max characteristics and specifications are guaranteed over all Recommended Operating Conditions.

• Typical characteristics and specifications are measured at nominal supply voltages and T

• VDDA = +3.3V ±10%; GNDA = GNDD = 0V. All voltages with respect to 0V.

• MCLK = 4.096MHz.

Parameter Symbol Min Typ Max Unit

Master Clock Characteristics

XIN Clock Frequency

Internal Gate Oscillator MCLK 2.5 4.096 5 MHz

XIN Clock Duty Cycle 40 - 60 %

Filter Characteristics

Phase Compensation Range

(60Hz, OWR = 4000Hz) -10.79 - +10.79 °

Input Sampling Rate - MCLK/8 - Hz Digital Filter Output Word Rate High-pass Filter Corner Frequency

(Both channels) OWR - MCLK/1024 - Hz

-3dB -2.0-Hz

Input/Output Characteristics

High-level Input Voltage (All Pins) V

Low-level Input Voltage (All Pins) V

High-level Output Voltage

(Note 12) All Other Outputs, I

Low-level Output Voltage

(Note 12) All Other Outputs, I

DO1-DO3, I

=+10mA

out

=+5mA

out

=-12mA

out

=-5mA

Input Leakage Current I

3-state Leakage Current I

Digital Output Pin Capacitance C

out

0.6(VDDA) - - V

--0.6V

VDDA-0.3 VDDA-0.3

-±1±10µA

--±10µA

-5-pF

= 25°C.

0.5

V V

Notes: 11. All measurements performed under static conditions.

12. XOUT pin used for crystal only. Typical drive current <1mA.

DS980F3 13

CS5480

SWITCHING CHARACTERISTICS

• Min / Max characteristics and specifications are guaranteed over all Recommended Operating Conditions.

• Typical characteristics and specifications are measured at nominal supply voltages and T

• VDDA = +3.3V ±10%; GNDA = GNDD = 0V. All voltages with respect to 0V.

• Logic Levels: Logic 0 = 0V, Logic 1 = VDDA.

Parameter Symbol Min Typ Max Unit

Rise Times

(Note 13) Any Digital Output Except DO1-DO3

Fall Times

(Note 13) Any Digital Output Except DO1-DO3

DO1-DO3

rise

fall

Start-up

Oscillator Start-up Time

XTAL = 4.096MHz (Note 14) t

ost

SPI Timing

Serial Clock Frequency (Note 15) SCLK - - 2 MHz

Serial Clock

Enable to SCLK Falling t

Data Set-up Time prior to SCLK Rising t

Data Hold Time After SCLK Rising t

SCLK Rising Prior to CS

Disable t

SCLK Falling to New Data Bit t

Rising to SDO Hi-Z t

Pulse Width High

Pulse Width Low

200 200

50 - - ns

100 - - ns

UART Timing

Enable to RX START bit t

STOP bit to CS

Disable to TX IDLE Hold Time t

Notes: 13. Specified using 10% and 90% points on waveform of interest. Output loaded with 50 pF.

14. Oscillator start-up time varies with crystal parameters. This specification does not apply when using an external clock source.

15. The maximum SCLK is 2 MHz during a byte transaction. The minimum 1µs idle time is required on the SCLK between two

Disable

consecutive bytes.

= 25°C.

1.0

µs ns

-60-ms

ns ns

1--µs

--150ns

--250ns

5--ns

1--µs

--250ns

14 DS980F3

CS5480

SDO

SDI

SCLK

MSB

MSB-1

INTERMEDIAT E B ITS

LSB

Figure 7. SPI Data and Clock Timing

START LSB

LSB

DATA MS B STOP

START DATA MSB

STOP

IDLE

OPTIONAL OVERLAP INSTRUCTION *

IDLE

* Reading registers during the optional overlap instruction requires the st art to o ccur durin g the last byte tran smitted by the pa rt

Figure 8. Multi-device UART Timing

DS980F3 15

CS5480

ABSOLUTE MAXIMUM RATINGS

Parameter Symbol Min Typ Max Unit

DC Power Supplies

Input Current

Input Current for Power Supplies - - - ±50 -

Output Current

Power Dissipation

Input Voltage

Junction-to-Ambient Thermal Impedance

Ambient Operating Temperature T

Storage Temperature T

Notes: 16. VDDA and GNDA must satisfy [(VDDA) – (GNDA)]  + 4.0V.

17. Applies to all pins, including continuous overvoltage conditions at the analog input pins.

18. Transient current of up to 100 mA will not cause SCR latch-up.

19. Applies to all pins, except VREF±

20. Total power dissipation, including all input currents and output currents.

21. Applies to all pins.

(Note 16) VDDA -0.3 - +4.0 V

(Notes 17 and 18)

(Note 19)

(Note 20) PD -- 500mW

(Note 21) V

2 Layer Board 4 Layer Board

OUT



stg

-- ±10mA

-- 100mA

- 0.3 - (VDDA) + 0.3 V

55 46

-40 - 85 °C

-65 - 150 °C

°C/W °C/W

WARNING:

Operation at or beyond these limits may result in permanent damage to the device.

Normal operation is not guaranteed at these extremes.

16 DS980F3

4. SIGNAL FLOW DESCRIPTION

MUX

SINC

IIN2±

SINC

PGA

HPF

DELAY

CTRL

2

MUX

PMF

HPF

PMF

IIR

Phase

Shift

Config 2

DELAY

CTRL

INT

Regi sters

SYS

GAIN

... ...

I2FLT[1:0]V2FLT[1:0]

DCOFF

GAIN

... ...

FPCC2[8:0]CPCC2[1: 0]

...

IIR

Epsilon

From V Channel ADC

4th Order



Modulator

Figure 9. Signal Flow for V1, I1, P1, Q1 Measurements

MUX

SINC

IIN2±

SINC

PGA

HPF

DELAY

CTRL

2

MUX

PMF

HPF

PMF

IIR

Phase

Shift

Config 2

DELAY

CTRL

INT

Regi sters

SYS

GAIN

... ...

I2FLT[1:0]V2FLT[1:0]

DCOFF

GAIN

... ...

FPCC2[8:0]CPCC2[1: 0]

...

IIR

Epsilon

From V Channel ADC

4th Order



Modulator

Figure 10. Signal Flow for V2, I2, P2, and Q2 Measurements

The signal flow for voltage measurement, current measurement, and the other calculations is shown in

Figures 9, 10, and 11.

The signal flow consists of two current channels and a voltage channel. Even though the CS5480 has only one voltage channel or voltage analog signal input, there are two separate voltage digital signal paths (V1 and V2). Both V1 and V2 come from the same ADC output. Each current and voltage channel has its own differential input pin.

4.1 Analog-to-Digital Converters

All three input channels use fourth-order delta-sigma modulators to convert the analog inputs to single-bit digital data streams. The converters sample at a rate of MCLK/8. This high sampling provides a wide dynamic range and simplifies anti-alias filter design.

CS5480

4.2 Decimation Filters

The single-bit modulator output data is widened to 24 bits and down sampled to MCLK/1024 with low-pass decimation filters. These decimation filters are third-order Sinc filters. The outputs of the filters are passed through an IIR "anti-sinc" filter.

4.3 IIR Filters

The IIR filters are used to compensate for the amplitude roll-off of the decimation filters. The droop-correction filter flattens the magnitude response of the channel out to the Nyquist frequency, thus allowing for accurate measurements of up to 2kHz (MCLK = 4.096MHz). By default, the IIR filters are enabled. The IIR filters can be bypassed by setting the IIR_OFF bit in the Config2 register.

DS980F3 17

CS5480











Regis ters

MUX

...

APCM

Config 2

V1(V2)

I1 (I2)

P1 (P2)

Q1 (Q2)

ACOFF

(I2

ACOFF

)

S1 (S2)



PF1 (PF2)

RMS

(I2

RMS

)

RMS

(V2

RMS

)

AVG

(Q2

AVG

)

AVG

(P2

AVG

)

OFF

(Q2

OFF

)



OFF

(P2

OFF

)



Inverse

Figure 11. Low-rate Calculations

4.4 Phase Compensation

Phase compensation changes the phase of voltage relative to current by adding a delay in the decimation filters. The amount of phase shift is set by the PC register bits CPCCx[1:0] and FPCCx[8:0] for current channels. For voltage channels, only bits CPCCx[1:0] affect the delay.

Fine phase compensation control bits, FPCCx[8:0], provide up to 1/OWR delay in the current channels. Coarse phase compensation control bits, CPCCx[1:0], provide an additional 1/OWR delay in the current channel or up to 2/OWR delay in the voltage channel. Negative delay in voltage channel can be implemented by setting a longer delay in the current channel than the voltage channel. For a OWR of 4000Hz, the delay range is ±500µs, a phase shift of ±8.99° at 50Hz and ±10.79° at 60Hz. The step size is 0.008789° at 50Hz and

0.010547° at 60Hz.

4.5 DC Offset and Gain Correction

The system and CS5480 inherently have component tolerances and gain and offset errors, which can be removed using the gain and offset registers. Each measurement channel has its own set of gain and offset registers. For every instantaneous voltage and current sample, the offset and gain values are used to correct DC offset and gain errors in the channel (see section 7.

System Calibration on page 63 for more details).

4.6 High-pass and Phase Matching Filters

Optional high-pass filters (HPF in Figures 9 and 10) remove any DC component from the selected signal paths. Each power calculation contains a current and voltage channel. If an HPF is enabled in only one channel, a phase matching filter (PMF) should be

applied to the other channel to match the phase response of the HPF. For AC power measurement, high-pass filters should be enabled on the voltage and current channels. For information about how to enable and disable the HPF or PMF on each channel, refer to section 6.6.3 Configuration 2 (Config2) – Page 16,

Address 0 on page 40.

4.7 Digital Integrators

Optional digital integrators (INT in Figures 9 and 10) are implemented on both current channels (I1, I2) to compensate for the 90º phase shift and 20dB/decade gain generated by the Rogowski coil current sensor. When a Rogowski coil is used as the current sensor, the integrator (INT) should be enabled on that current channel. For information about how to enable and disable the INT on each current channel, refer to section

6.6.3 Configuration 2 (Config2) – Page 16, Address 0 on

page 40.

4.8 Low-rate Calculations

All the RMS and power results come from low-rate calculations by averaging the output word rate (OWR) instantaneous values over N samples where N is the value stored in the SampleCount register. The low-rate interval or averaging period is N divided by OWR (4000Hz if MCLK = 4.096MHz). The CS5480 provides two averaging modes for low-rate calculations: Fixed Number of Samples Averaging mode and Line-cycle Synchronized Averaging mode. By default, the CS5480 averages with the Fixed Number of Samples Averaging mode. By setting the AVG_MODE bit in the Config2 register, the CS5480 will use the Line-cycle Synchronized Averaging mode.

18 DS980F3

CS5480

RMS

n0=

N1–



--------------------

RMS

n0=

N1–



----------------------

[Eq. 1]

RMSIRMS

=

[Eq. 2]

AVG

[Eq. 3]

ACTIVE

----------------------

[Eq. 4]

4.8.1 Fixed Number of Samples Averaging

N is the preset value in the SampleCount register and should not be set less than 100. By default, the Sample- Count is 4000. With MCLK = 4.096MHz, the averaging period is fixed at N/4000 = 1 second, regardless of the line frequency.

4.8.2 Line-cycle Synchronized Averaging

When operating in Line-cycle Synchronized Averaging mode, and when line frequency measurement is enabled (see section 5.4 Line Frequency Measurement on page 22), the CS5480 uses the voltage (V) channel zero crossings and measured line frequency to automatically adjust N such that the averaging period will be equal to the number of half line-cycles in the CycleCount register. For example, if the line frequency is 51Hz, and the CycleCount register is set to 100, N will be 4000

(100 / 2) / 51 = 3921 during continuous

conversion. N is self-adjusted according to the line frequency; therefore, the averaging period is always close to the whole number of half line-cycles, and the low-rate calculation results will minimize ripple and maximize resolution, especially when the line frequency varies. Before starting a low-rate conversion in Line-cycle Synchronized Averaging mode, the SampleCount register should not be changed from its default value of 4000, and bit AFC of the Config2 register must be set. During continuous conversion, the host processor should not change the SampleCount register.

4.8.3 RMS Current and Voltage

The root mean square (RMS in Figure 11) calculations are performed on N instantaneous current and voltage samples using Equation 1:

4.8.5 Reactive Power

Instantaneous reactive power (Q1, Q2) are sample rate results obtained by multiplying instantaneous current (I1, I2) by instantaneous quadrature voltage (V1Q, V2Q), which are created by phase shifting the instantaneous voltage (V1, V2) 90 degrees using first-order integrators (see Figures 9 and 11). The gain of these integrators is inversely related to line frequency, so their gain is corrected by the Epsilon register, which is based on line frequency. Reactive power (Q1

AVG

, Q2

) is generated by integrating the

AVG

instantaneous quadrature power over N samples.

4.8.6 Apparent Power

By default, the CS5480 calculates the apparent power (S1, S2) as the product of RMS voltage and current as shown in Equation 2:

The CS5480 also provides an alternate apparent power calculation method, which uses real power (P1

) and reactive power (Q1

AVG

, Q2

AVG

) to calcu-

late apparent power, as shown in Equation 3:

The APCM bit in the Config2 register controls which method is used for apparent power calculation.

4.8.7 Peak Voltage and Current

Peak current (I1 (V

) are calculated over N samples and recorded in

PEAK

the corresponding channel peak register documented in the register map. This peak value is updated every N samples.

PEAK

, I2

) and peak voltage

PEAK

4.8.8 Power Factor

Power factor (PF1, PF2) is active power divided by apparent power as shown in Equation 4. The sign of the power factor is determined by the active power.

4.8.4 Active Power

The instantaneous voltage and current samples are multiplied to obtain the instantaneous power (P1, P2) (see Figures 9 and 11). The product is then averaged over N samples to compute active power (P1

AVG

DS980F3 19

AVG

4.9 Average Active Power Offset

The average active power offset registers, P1

(P2 resident in the system not originating from the power line. Residual power offsets are usually caused by crosstalk into current channels from voltage channels, or from ripple on the meter’s or chip’s power supply, or from inductance from a nearby transformer.

), can be used to offset erroneous power sources

OFF

CS5480

These offsets can be either positive or negative, indicating crosstalk coupling either in phase or out of phase with the applied voltage input. The power offset registers can compensate for either condition.

To use this feature, measure the average power at no load. Take the measured result (from the P1 (P2

) register), invert (negate) the value, and write it

AVG

to the associated average active power offset register,

OFF

(P2

OFF

4.10 Average Reactive Power Offset

The average reactive power offset registers, Q1 (Q2

), can be used to offset erroneous power

OFF

sources resident in the system not originating from the

OFF

power line. Residual reactive power offsets are usually caused by crosstalk into current channels from voltage channels, or from ripple on the meter’s or chip’s power supply, or from inductance from a nearby transformer.

These offsets can be either positive or negative, depending on the phase angle between the crosstalk coupling and the applied voltage. The reactive power offset registers can compensate for either condition. To use this feature, measure the average reactive power at no load. Take the measured result from the

AVG

(Q2

) register, invert (negate) the value and

AVG

write it to the associated reactive power offset register,

OFF

(Q2

OFF

20 DS980F3

CS5480

VDDA

POR_Rough_VD DA

POR_F ine_V DDA

VDDD

POR_Rough_VDDD

POR_Fine_VDDD

POR_F ine_V DDA POR_Fine_VDDD

Master Reset

130ms

th1

th2

th5

th6

th3

th4

th7

th8

Figure 12. Power-on Reset Timing

5. FUNCTIONAL DESCRIPTION

5.1 Power-on Reset

The CS5480 has an internal power supply supervisor circuit that monitors the VDDA and VDDD power supplies and provides the master reset to the chip. If any of these voltages are in the reset range, the master reset is triggered.

The CS5480 has dedicated power-on reset (POR) circuits for the analog supply and digital supply. During power-up, both supplies have to be above the rising threshold for the master reset to be de-asserted.

Each POR is divided into two blocks: rough and fine. Rough POR triggers the fine POR. Rough POR depends only on the supply voltage. The trip point for the fine POR is dependent on bandgap voltage for precise control. The POR circuit also acts as a brownout detect. The fine POR detects supply drops and asserts the master reset. The rough and fine PORs have hysteresis in their rise and fall thresholds, which prevents the reset signal from chattering.

Figure 9 shows the POR outputs for each of the power supplies. The POR_Fine_VDDA and POR_Fine_VDDD signals are AND-ed to form the actual power-on reset signal to the digital circuity. The digital circuitry, in turn, holds the master reset signal for 130ms and then de-asserts the master reset.

Typ i cal P OR

Threshold

VDDA

VDDD

Table 1. POR Thresholds

Rising Falling

Rough

Fine

Rough

Fine

= 2.34V V

th1

= 2.77V V

th2

= 1.20V V

th3

= 1.51V V

th4

th6

th5

th8

th7

=2.06V

=2.59V

=1.06V

=1.42V

5.2 Power Saving Modes

Power Saving modes for the CS5480 are accessed through the Host Commands (see section 6.1 Host

Commands on page 29).

• Standby: Powers down all the ADCs, rough buffer, and the temperature sensor. Standby mode disables the system time calculations. Use the wake-up command to come out of standby mode.

• Wake-up: Clears the ADC power-down bits and starts the system time calculations.

After any of these commands are completed, the DRDY bit is set in the Status0 register.

5.3 Zero-crossing Detection

Zero-crossing detection logic is implemented in the CS5480. One current and one voltage channel can be selected for zero-crossing detection. The IZX_CH control bit in the Config0 register is used to select the zero-crossing channel. A low-pass filter can be enabled by setting ZX_LPF bit in register Config2. The low-pass filter has a cut-off frequency of 80Hz. It is used to eliminate any harmonics and help the zero-crossing detection on the 50Hz or 60 Hz fundamental component. The zero-crossing level registers are used to set the minimum threshold over which the channel peak has to exceed in order for the zero-crossing detection logic to function. There are two separate zero-crossing level registers: VZX for the voltage channels, and IZX for the current channels.

is the threshold

LEVEL

is the threshold

LEVEL

DS980F3 21

CS5480

LEVEL

IZX

LEVEL

If |V

PEAK

| > VZX

LEVEL

, then voltage zero-crossing detection is enabled.

If |I

PEAK

| > IZX

LEVEL

, then current zero-crossing detection is enabled.

Zero-crossing output on DOx pin

Pulse width = 250μs

V(t), I(t)

DOx

If |V

PEAK

|  VZX

LEVEL

, then voltage zero-crossing detection is disable

If |I

PEAK

|  IZX

LEVEL

, then current zero-crossing detection is disabled.

Figure 13. Zero-crossing Level and Zero-crossing Output on DOx

5.4 Line Frequency Measurement

If the Automatic Frequency Calculation (AFC) bit in the Config2 register is set, the line frequency measurement on a voltage channel will be enabled. The line frequency measurement is based on a number of voltage channel zero crossings. This number is 100 by default and configurable through the ZX

6.6.7 on page 43). The Epsilon register will be updated

automatically with the line frequency information. The Frequency Update (FUP) bit in the Status0 interrupt status register is set when the frequency calculation is completed. When the line frequency is 50Hz and the

NUM

every one second with a resolution of less than 0.1%. A bigger zero-crossing number in the ZX increase both line frequency measurement resolution

NUM

and period. Note that the CS5480 line frequency measurement function does not support the line frequency out of the range of 40Hz to 75Hz.

The Epsilon register is also used to set the gain of the 90° phase shift filter used in the quadrature power calculation. The value in the Epsilon register is the ratio of the line frequency to the output word rate (OWR). For 50Hz line frequency and 4000Hz OWR, Epsilon is 50/4000 (0.0125) (the default). For 60Hz line frequency, it is 60/4000 (0.015).

NUM

22 DS980F3

CS5480

2÷

RMS

N÷



AVG

SUM

2÷

N÷



AVG

SUM

2÷

SUM

VFIX

(Config 2)

MCFG[1:0]

(Config2)

ICHAN

(IHOLD = 1)

Figure 14. Channel Selection and Tamper Protection Flow

Meter Mode

MCFG

[1:0]

Total Power

Calculations

1V-2I 01

1V-1I-1N

(I1

RMS

> I2

RMS

(P1

AVG

> P2

AVG

(Default)

1V-1I-1N

(I1

RMS

< I2

RMS

(P1

AVG

< P2

AVG

(Default)

5.5 Meter Configuration Modes

There are two distinct meter configuration modes in the CS5480 that affect how the total active, reactive, and apparent power calculations are performed. The CS5480 has power results for each current channel as well as total power registers (P registers are calculated from either one or both channels, depending on the meter configuration modes. See Table 2 for power calculations in each mode.

The Meter Configuration (MCFG) bits in the configuration (Config2) register set the meter configuration modes. For each meter mode, the current channels are interpreted differently. In the one voltage and two line currents (1V – 2I) mode, the CS5480 treats the two currents as individual contributors to the overall power. In the one voltage, one line current, and one neutral current (1V – 1I – 1N) mode, the currents are treated as duplicate copies of the same load current, and the total power is calculated from the highest current or the one the customer has specified. The MCFG multiplexers in Figure 14 show the data path for both modes.

SUM

, Q

SUM

, and S

). The total power

SUM

Table 2. Meter Configuration Modes

DS980F3 23

CS5480

Channel Select Level

(Ichan

LEVEL

)

2% minimum difference

Channel Select Level

(Ichan

LEVEL

)

2% minimum difference

Channel Select Minimum Amplitude

MIN

(IRMS

MIN

)

AVG

Channel 1 - Remains Active

Channel 2 - Active

Channel 1 - Active

Automatic Channel

Selection Region

Disabled Automatic Channel

Selection Region

Figure 15. Automatic Channel Selection

5.6 Tamper Detection and Correction

In the 1V-1I-1N meter configuration mode, the CS5480 provides flexibility for the user and application program to adjust the anti-tampering scheme automatically or manually. Automatic channel selection is enabled by default. For manual channel selection refer to section

5.6.1.2 Manual Channel Selection on page 25.

The CS5480 provides compensation for at least two forms of meter tampering — current and voltage tampering.

5.6.1 Anti-tampering on Current

In the 1V-1I-1N mode, current tampering is deterred by an automatic or manual channel selection scheme. A dedicated second neutral current input is provided in the event that the primary current input is impaired by tampering.

1 2 3

5.6.1.1 Automatic Channel Selection

Automatic channel selection is standard in the CS5480. When tampering is detected, the CS5480 will automatically select the channel with the greater Px nitude as the contributor to the total power registers. Using either Px

AVG

or Ix

magnitude depends on the setting

RMS

of the IVSP bit in the Config2 register.

To avoid repeated channel transitions at light load, the Channel Select Minimum Amplitude (P register sets a minimum level for automatic channel selection. When either P1 greater than P

MIN

(IRMS

AVG

(I1

MIN

) or P2

RMS

), the CS5480 will enable automatic channel selection. Within the automatic selection region, the Channel Select Level (Ichan sets a minimum difference that will allow an automatic channel change. The channel select level provides hysteresis to prevent repeated channel transitions that would occur when the primary line current and neutral current are nearly equal.

AVG

or Ix

MIN

AVG

LEVEL

RMS

(IRMS

(I2

RMS

) register

mag-

MIN

) is

))

Figure 15 shows how the automatic channel selection is performed. In this figure, the magnitudes of P1

are used for automatic channel selection (IVSP

AVG

= 0) and Ichan

•The P1

AVG

LEVEL

and P2 Select Minimum Amplitude (Ichan highest channel is active, P1

24 DS980F3

and

AVG

= 1.02.

must meet the Channel

AVG

in this example.

AVG

LEVEL

). The

• Even when the active channel (P1 the previously lower channel (P2

) moves below

AVG

), the channel

AVG

selection does not change.

• The new channel selection is only made when the difference between P1 2% x P1

AVG

or P2

AVG

> P1

and P2

x Ichan

AVG

is greater than

AVG

LEVEL

(1.02).

CS5480

SUM

Sign

SUM

Sign

P1 Sign

P2 Sign

Q1 Sign

Q2 Sign

DO1_OD (Config1)

DO2_OD (Config1)

DO3_OD (Config1)

(PulseCtrl) EPGxIN[3:0]

DOxMODE[3:0]

(Config1)

DO3

DO2

DO1

Hi-Z

Interrupt

SUM

AVG

PULSE RATE

EPGx_ON

(Config1)

MCLK

(PulseWidth) PW[7:0]

(PulseWidth) FR EQ_RN G[3:0]

0000

0001

0010

0011

0100

0101

0110

0111

1000

Energy Pulse Generation (EPG1)

Energy Pulse Generation (EPG2)

En er gy Pul se Generati on (EPG3)

Digital Output Mux (DO3)

Digital Output Mux (DO2)

0000

0001

0010

0011

0100

0101

0110

0111

1000

1001

1010

1011

1100

1101

1110

1111

Digital Output Mux (DO1)

RESERVED

V1/V2 Crossing

I1/I2 C rossing

Figure 16. Energy Pulse Generation and Digital Output Control

5.6.1.2 Manual Channel Selection

In addition to automatic channel selection anti-tampering scheme, the CS5480 allows the user or application program to select the more appropriate energy channel manually. Configuration 2 (Config2) register bit IHOLD disable automatic channel selection, and ICHAN forces the selection of the contributor to the total power registers (see Figure 14).

5.6.2 Anti-tampering on Voltage

An internal RMS voltage reference is also available in the event that the voltage input has been compromised by tampering.

If the user application detects the voltage input has been impaired, it may choose to use the fixed internal RMS voltage reference in active power calculations by setting the VFIX bit in the Configuration 2 (Config2) register. The value of the Voltage Fixed RMS Reference

(VF

) register is by default 0.707107 (full-scale RMS)

RMS

but can be changed by the application program. Figure

14 shows the entry point for the VF

has no phase relationship to I1 the VF

only affects the active power calculation

RMS

or I2

value. VF

. Therefore,

RMS

paths.

5.7 Energy Pulse Generation

The CS5480 provides three independent energy pulse generation blocks (EPG1, EPG2, and EPG3) in order to simultaneously output active, reactive, and apparent energy pulses on any of the three digital output pins (DO1, DO2, and DO3). The energy pulse frequency is proportional to the magnitude of the power. The energy pulse output is commonly used as the test output of a power meter. energy pulses to accumulate the energy

The host microcontroller can also use the

(see Figure 16)

DS980F3 25

CS5480

Level

Duration

Figure 17. Sag, Swell, and Overcurrent Detect

After reset, all three energy pulse generation blocks are disabled (DOxMODE[3:0] = Hi-Z). To output a desired energy pulse to a DOx pin, follow the steps below:

1. Write to register PulseWidth (page 0, address 8) to select the energy pulse width and pulse frequency range.

2. Write to register PulseRate (page 18, address 28) to select the energy pulse rate.

3. Write to register PulseCtrl (page 0, address 9) to select the input to each energy pulse generation block.

4. Write ‘1’ to bit EPGx_ON of register Config1 (page 0, address 1) to enable the appropriate energy pulse generation blocks.

5. Wait at least 0.1s.

6. Write bits DOxMODE[3:0] of register Config1 to select DOx to output pulses from the appropriate energy pulse generation block.

7. Send DSP instruction (0xD5) to begin continuous conversion.

5.7.1 Pulse Rate

Before configuring the PulseRate register, the full-scale pulse rate needs to be calculated and the frequency range needs to be specified through FREQ_RNG[3:0] bits in the PulseWidth register. Refer to section 6.6.6

Pulse Output Width (PulseWidth) – Page 0, Address 8

on page 43. The FREQ_RNG[3:0] bits should be set to b[0110]. For example, if a meter has the meter constant of 1000imp/ kWh, a maximum voltage (U and a maximum current (I

) of 100A, the maximum

MAX

pulse rate is:

[1000x(240x100/1000)] / 3600 = 6.6667Hz.

Assume the meter is calibrated with U and the Scale register contains the default value of 0.6. After gain calibration, the power register value will be

0.36, which represents 240x 100 = 24kW or 6.6667Hz

pulse output rate. The full-scale pulse rate is:

= 6.6667/ 0.36 = 18.5185Hz.

out

The CS5480 pulse generation block behaves as follows:

• The pulse rate generated by full-scale (1.0decimal) power register:

=(PulseRatex2000)/2

OUT

FREQ_RNG

•The PulseRate register value is:

PulseRate = (F

OUT

FREQ_RNG

= (18.5186x 64) / 2000

= 0.5925952

= 0x4BDA29

) of 240V,

MAX

and I

MAX

)/2000

MAX

5.7.2 Pulse Width

The PulseWidth register defines the Active-low time of each energy pulse:

Active-low = 250µs+(PulseWidth/64000).

By default, the PulseWidth register value is 1, and the Active-low time of each energy pulse is 265.6µs. Note that the pulse width should never exceed the pulse period.

5.8 Voltage Sag, Voltage Swell, and Overcurrent Detection

Voltage sag detection is used to determine when the voltage falls below a predetermined level for a specified interval of time (duration). Voltage swell and overcurrent detection determines when the voltage or current rises above a predetermined level for a specified interval of time.

The duration is set by the value in the V1Sag (V2Sag

I1Over

to zero (default) disables the detect feature for the given channel. The value is in output word rate (OWR) samples. The predetermined level is set by the values in the V1Sag (V2Swell registers.

For each enabled input channel, the measured value is rectified and compared to the associated level register. Over the duration window, the number of samples above and below the level are counted. If the number of samples below the level exceeds the number of samples above, a Status0 register bit V1SAG (V2SAG)

is set, indicating a sag condition. If the number of samples above the level exceeds the number of samples below, a Status0 register bit V1SWELL (V2SWELL) or I1OVER (I2OVER) is set, indicating a swell or overcurrent condition (see Figure 17).

), V1Swell

DUR

(I2Over

DUR

LEVEL

(V2Swell

DUR

) registers. Setting any of these

DUR

(V2Sag

LEVEL

), and I1Over

LEVEL

DUR

), V1Swell

(I2Over

DUR

), and

LEVEL

)

26 DS980F3

CS5480

Figure 18. Phase Sequence A, B, C for Rising Edge Transition

-2

Phase A Channel

-2

Phase B Channel

-2

Phase C Channel

Write 0x16 to

PSDC Register

Start on the Falling Edge on the RX Pin

Stop

Phase C Count

Phase B Count

Phase A Count

5.9 Phase Sequence Detection

Polyphase meters using multiple CS5480 devices may be configured to sense the succession of voltage zero-crossings and determine which phase order is in service. The phase sequence detection within CS5480 involves counting the number of OWR samples from a starting point to the next voltage zero-crossing rising edge or falling for each phase. By comparing the count for each phase, the phase sequence can be easily determined: the smallest count is first, and the largest count is last.

The phase sequence detection and control register PSDC provides the count control, zero-crossing direction and count results. Writing '0' to bit DONE and '10110' to bits CODE[4:0] of the PSDC register followed by a falling edge on the RX pin will initiate the phase sequence detection circuit. The RX pin must be held low for a minimum of 500ns. When the device is in UART mode, it is recommended that a 0xFF command be written to all parts to start the phase sequence detection. Multiple CS5480 devices in a polyphase meter must receive the register writing and the RX falling edge at the same time so that all CS5480 devices starts to count simultaneously. Bit DIR of PSDC register specifies the direction of the next zero crossing at which the count stops. If bit DIR is '0', the count stops at the next negative-to-positive zero crossing. If bit DIR is '1', the count stops at the next positive-to-negative zero crossing. When the count stops, the DONE bit will be set by the CS5480, and then the count result of each phase may be read from bits PSCNT[6:0] of the PSDC register.

If the PSCNT[6:0] bits are equal to 0x00, 0x7F or greater than 0x64 (for 50Hz) or 0x50 (for 60Hz), then a measurement error has occurred, and the measurement results should be disregarded. This could happen when the voltage input signal amplitude is lower than the amplitude specified in the VZX

LEVEL

To determine the phase order, the PSCNT[6:0] bit counts from each CS5480 are sorted in ascending order. Figure 18 and Figure 19 illustrate how phase sequence detection is performed.

Phase sequences A, B, and C for the default rising edge transition are illustrated in Figure 18. The PSCNT[6:0] bits from the CS5480 on phase A will have the lowest count, followed by the PSCNT[6:0] bits from the CS5480 on phase B with the middle count, and the PSCNT[6:0] bits from the CS5480 on phase C with the highest count.

Phase sequences C, B, and A for rising edge transition are illustrated in Figure 19. The PSCNT[6:0] bits from the CS5480 on phase C will have the lowest count, followed by the PSCNT[6:0] bits from the CS5480 on phase B with the middle count, and the PSCNT[6:0] bits from the CS5480 on phase A with the highest count.

5.10 Temperature Measurement

The CS5480 has an internal temperature sensor, which is designed to measure temperature and optionally compensate for temperature drift of the voltage reference. Temperature measurements are stored in the Temperature register (T), which, by default, is configured to a range of ±128 degrees on the Celsius (°C) scale.

DS980F3 27

CS5480

-2

Phase A Channel

-2

Phase B Channel

-2

Phase C Channel

Stop

Phase C Count

Phase B Count

Phase A Count

Write 0x16 to

PSDC Register

Start on the Falling Edge on the RX Pin

Figure 19. Phase Sequence C, B, A for Rising Edge Transition

The application program can change both the scale and range of temperature by changing the Temperature Gain (T

) and Temperature Offset (T

GAIN

) registers.

OFF

T updates every 2240 output word rate (OWR) samples.

The Status0 register bit TUP indicates when T is updated.

be write-protected from the serial interface. Setting the HOST_LCK[4:0] bits to 0x09 disables the write-protection mode.

For registers that are DSP lockable, HOST lockable, or both, refer to sections 6.2 Hardware Registers

Summary (Page 0) on page 31, 6.3 Software Registers Summary (Page 16) on page 33, and 6.4 Software

5.11 Anti-Creep

The anti-creep (no-load threshold) is used to determine if a no-load condition is detected. The |P |Q

| are compared to the value in the No-Load

SUM

Threshold register (Load are less than this threshold, then P forced to zero. If S register, then S

SUM

is forced to zero.

SUM

). If both |P

MIN

SUM

and Q

is less than the value in Load

SUM

| and |Q

SUM

| and

SUM

are

MIN

5.12 Register Protection

To prevent the critical configuration and calibration registers from unintended changes, the CS5480 provides two enhanced register protection mechanisms: write protection and automatic checksum calculation.

5.12.1 Write Protection

Setting the DSP_LCK[4:0] bits in the RegLock register to 0x16 enables the CS5480 DSP lockable registers to be write-protected from the calculation engine. Setting the DSP_LCK[4:0] bits to 0x09 disables the write-protection mode.

Setting the HOST_LCK[4:0] bits in the RegLock register to 0x16 enables the CS5480 HOST lockable registers to

Registers Summary (Page 17) on page 35.

5.12.2 Register Checksum

All the configuration and calibration registers are protected by checksum, if enabled. Refer to 6.2

Hardware Registers Summary (Page 0) on page 31, 6.3 Software Registers Summary (Page 16) on page 33,

and 6.4 Software Registers Summary (Page 17) on page 35. The checksum for all registers marked with an asterisk symbol ( cycle. The checksum result is stored in the RegChk register. After the CS5480 has been fully configured and loaded with the calibrations, the host microcontroller should keep a copy of the checksum (RegChk_Copy) in its memory. In normal operation, the host microcontroller can read the RegChk register and compare it with the saved copy of the RegChk register. If the two values mismatch, a reload of configurations and calibrations into the CS5480 is necessary.

The automatic checksum computation can be disabled by setting the REG_CSUM_OFF bit in the Config2 register.

*) is calculated once every low-rate

28 DS980F3

6. HOST COMMANDS AND REGISTERS

SD I/RX

Page Select Cmd.

SDO/TX

SDI/RX

DATA DATA DATA

Read Cmd.

SD I/RX

DATA DATA DATA

Write Cmd.

SD I/RX

Inst ruction

6.1 Host Commands

The first byte sent to the CS5480 SDI/ RX pin contains the host command. Four types of host commands are required to read and write registers and instruct the calculation engine. The two most significant bits (MSBs) of the host command defines the function to be performed. The following table depicts the types of commands.

Table 3. Command Format

Function Binary Value Note

Read

Write

Page Select

Instruction

0 0 A

5A4A3A2A1A0

0 1 A

5A4A3A2A1A0

1 0 P

5P4P3P2P1P0

1 1 C

5C4C3C2C1C0

specifies the

[5:0]

specifies the

[5:0]

page.

specifies the

[5:0]

instruction.

CS5480

6.1.1.3 Register Write

A register write command is designated by setting the two MSBs of the command to binary ‘01’. The lower 6 bits of the register write command are the lower 6 bits of the 12-bit register address. A register write command must be followed by 3 bytes of data.

Figure 22. Byte Sequence for Register Write

6.1.2 Instructions

An instruction command is designated by setting the two MSBs of the command to binary '11'. An Instruction command will interrupt any process currently running and initiate a new process in the CS5480.

6.1.1 Memory Access Commands

The CS5480 memory has 12-bit addresses and is organized as P

5P4P3P2P1P0A5A4A3A2A1A0

in 64 pages of 64 addresses each. The higher 6 bits specify the page number. The lower 6 bits specify the address within the selected page.

6.1.1.1 Page Select

A page select command is designated by setting the two MSBs of the command to binary ‘10’. The page select command provides the CS5480 with the page number of the register to access. Register read and write commands access 1 of 64 registers within a specified page. Subsequent register reads and writes can be performed once the page has been selected.

Figure 20. Byte Sequence for Page Select

6.1.1.2 Register Read

A register read is designated by setting the two MSBs of the command to binary ‘00’. The lower 6 bits of the register read command are the lower 6 bits of the 12-bit register address. After the register read command has been received, the CS5480 will send 3 bytes of register data onto the SDO/TX pin.

Figure 21. Byte Sequence for Register Read

Figure 23. Byte Sequence for Instructions

These new processes include calibration, power control, and soft reset. The following table depicts the types of instructions. Note that when the CS5480 is in continuous conversion mode, an unexpected or invalid instruction command could cause the device to stop continuous conversion and enter an unexpected operation mode. The host processor should keep monitoring the CS5480 operation status and react accordingly.

Table 4. Instruction Format

Function Binary Value Note

specifies the

[5]

instruction type: 0 = Controls 1 = Calibrations

For calibrations, C

specifies the

[4:3]

type of calibration. *AC Offset calibration valid only for current

channel For calibrations, C

specifies the

[2:0]

channel(s).

Controls

Calibrations

0 C

4C3C2C1C0

0 00001 - Software Reset 0 00010 - Standby 0 00011 - Wakeup 0 10100 - Single Conv. 0 10101 - Continuous Conv. 0 11000 - Halt Conv.

1 C

4C3C2C1C0

1 00C2C1C0 DC Offset

1 10C

1 11C

1C4C3C2C1C

1 C4C3 0 0 1 I1 1 C

4C3

1 C

4C3

1 C

4C3

1 C

4C3

AC Offset*

2C1C0

0 1 0 V1 0 1 1 I2 1 0 0 V2 1 1 0 All Four

2C1C0

Gain

DS980F3 29

6.1.3 Checksum

SDI/RX

ChecksumPage Select Cmd.

SDO/TX

SDI/RX

CHECKSUM

DATA DATA DATA C HECKSUM

Read Cmd.

SDI/RX

DATA DATA DATA CHECKSUMWrite Cmd.

SDI/RX

ChecksumInstruction

Page Select

Instruction

Read Command

Write Command

To improve the communication reliability on the serial interface, the CS5480 provides a checksum mechanism on transmitted and received signals. Checksum is disabled by default but can be enabled by setting the appropriate bit in the SerialCtrl register. When enabled, both host and CS5480 are expected to send one additional checksum byte after the normal command byte and the applicable 3-byte register data has been transmitted.

The checksum is calculated by subtracting each transmit byte from 0xFF. Any overflow is truncated and the result wraps. The CS5480 executes the command only if the checksum transmitted by the host matches the checksum calculated locally. Otherwise, it sets a status bit (RX_CSUM_ERR in the Status0 register), ignores the command, and clears the serial interface in preparation for the next transmission.

CS5480

Figure 24. Byte Sequence for Checksum

6.1.4 Serial Time Out

In case a transaction from the host is not completed (for example, a data byte is missing in a register write), a time out circuit will reset the interface after 128ms. This will require that each byte be sent from the host within 128ms of the previous byte.

30 DS980F3

CS5480

6.2 Hardware Registers Summary (Page 0)

Address2RA[5:0] Name Description

0* 00 0000 Config0 Configuration 0 Y Y 0x C0 2000 1* 00 0001 Config1 Configuration 1 Y Y 0x 00 EEEE 2 00 0010 - Reserved 3* 00 0011 Mask Interrupt Mask Y Y 0x 00 0000 4 00 0100 - Reserved 5* 00 0101 PC Phase Compensation Control Y Y 0x 00 0000 6 00 0110 - Reserved 7* 00 0111 SerialCtrl UART Control Y Y 0x 02 004D 8* 00 1000 PulseWidth Energy Pulse Width Y Y 0x 00 0001 9* 00 1001 PulseCtrl Energy Pulse Control Y Y 0x 00 0000 10 00 1010 - Reserved 11 00 1011 - Reserved 12 00 1100 - Reserved 13 00 1101 - Reserved 14 00 1110 - Reserved 15 00 1111 - Reserved 16 01 0000 - Reserved 17 01 0001 - Reserved 18 01 0010 - Reserved 19 01 0011 - Reserved 20 01 0100 - Reserved 21 01 0101 - Reserved 22 01 0110 - Reserved 23 01 0111 Status0 Interrupt Status N N 0x 80 0000 24 01 1000 Status1 Chip Status 1 N N 0x 80 1800 25 01 1001 Status2 Chip Status 2 N N 0x 00 0000 26 01 1010 - Reserved 27 01 1011 - Reserved 28 01 1100 - Reserved 29 01 1101 - Reserved 30 01 1110 - Reserved 31 01 1111 - Reserved 32 10 0000 - Reserved 33 10 0001 - Reserved 34* 10 0010 RegLock Register Lock Control N N 0x 00 0000 35 10 0011 - Reserved 36 10 0100 V1 37 10 0101 I1 38 10 0110 V2 39 10 0111 I2

PEAK

V1 Peak Voltage N Y 0x 00 0000 I1 Peak Current N Y 0x 00 0000 V2 Peak Voltage N Y 0x 00 0000

I2 Peak Current N Y 0x 00 0000 40 10 1000 - Reserved 41 10 1001 - Reserved 42 10 1010 - Reserved 43 10 1011 - Reserved 44 10 1100 - Reserved 45 10 1101 - Reserved 46 10 1110 - Reserved 47 10 1111 - Reserved 48 11 0000 PSDC Phase Sequence Detection & Control N Y 0x 00 0000 49 11 0001 - Reserved 50 11 0010 - Reserved -

DSP3HOST3Default

DS980F3 31

51 11 0011 - Reserved 52 11 0100 - Reserved 53 11 0101 - Reserved 54 11 0110 - Reserved 55 11 0111 ZX 56 11 1000 - Reserved 57 11 1001 - Reserved 58 11 1010 - Reserved 59 11 1011 - Reserved 60 11 1100 - Reserved 61 11 1101 - Reserved 62 11 1110 - Reserved 63 11 1111 - Reserved -

Notes: (1) Warning: Do not write to unpublished or reserved register locations.

(2) * Registers with checksum protection. (3) Registers that can be set to write protect from DSP and/or HOST.

NUM

Num. Zero Crosses used for Line Freq. Y Y 0x 00 0064

CS5480

32 DS980F3

6.3 Software Registers Summary (Page 16)

Address2RA[5:0] Name Description

0* 00 0000 Config2 Configuration 2 Y Y 0x 00 0200 1 00 0001 RegChk Register Checksum N Y 0x 00 0000 2 00 0010 I1 I1 Instantaneous Current N Y 0x 00 0000 3 00 0011 V1 V1 Instantaneous Voltage N Y 0x 00 0000 4 00 0100 P1 Instantaneous Power 1 N Y 0x 00 0000 5 00 0101 P1 6 00 0110 I1 7 00 0111 V1

AVG

RMS

Active Power 1 N Y 0x 00 0000

I1 RMS Current N Y 0x 00 0000

V1 RMS Voltage N Y 0x 00 0000 8 00 1000 I2 I2 Instantaneous Current N Y 0x 00 0000 9 00 1001 V2 V2 Instantaneous Voltage N Y 0x 00 0000 10 00 1010 P2 Instantaneous Power 2 N Y 0x 00 0000 11 00 1011 P2 12 00 1100 I2 13 00 1101 V2 14 00 1110 Q1

AVG

RMS

AVG

Active Power 2 N Y 0x 00 0000

I2 RMS Current N Y 0x 00 0000

V2 RMS Voltage N Y 0x 00 0000

Reactive Power 1 N Y 0x 00 0000 15 00 1111 Q1 Instantaneous Reactive Power 1 N Y 0x 00 0000 16 01 0000 Q2

AVG

Reactive Power 2 N Y 0x 00 0000 17 01 0001 Q2 Instantaneous Reactive Power 2 N Y 0x 00 0000 18 01 0010 - Reserved 19 01 0011 - Reserved 20 01 0100 S1 Apparent Power 1 N Y 0x 00 0000 21 01 0101 PF1 Power Factor 1 N Y 0x 00 0000 22 01 0110 - Reserved 23 01 0111 - Reserved 24 01 1000 S2 Apparent Power 2 N Y 0x 00 0000 25 01 1001 PF2 Power Factor 2 N Y 0x 00 0000 26 01 1010 - Reserved 27 01 1011 T Temperature N Y 0x 00 0000 28 01 1100 - Reserved 29 01 1101 P 30 01 1110 S 31 01 1111 Q 32* 10 0000 I1 33* 10 0001 I1 34* 10 0010 V1 35* 10 0011 V1 36* 10 0100 P1 37* 10 0101 I1 38* 10 0110 Q1 39* 10 0111 I2 40* 10 1000 I2 41* 10 1001 V2 42* 10 1010 V2 43* 10 1011 P2 44* 10 1100 I2 45* 10 1101 Q2

SUM

DCOFF

GAIN

DCOFF

GAIN

OFF

ACOFF

OFF

DCOFF

GAIN

DCOFF

GAIN

OFF

ACOFF

OFF

Total Active Power N Y 0x 00 0000

Total Apparent Power N Y 0x 00 0000

Total Reactive Power N Y 0x 00 0000

I1 DC Offset Y Y 0x 00 0000

I1 Gain Y Y 0x 40 0000

V1 DC Offset Y Y 0x 00 0000

V1 Gain Y Y 0x 40 0000

Average Active Power 1 Offset Y Y 0x 00 0000

I1 AC Offset Y Y 0x 00 0000

Average Reactive Power 1 Offset Y Y 0x 00 0000

I2 DC Offset Y Y 0x 00 0000

I2 Gain Y Y 0x 40 0000

V2 DC Offset Y Y 0x 00 0000

V2 Gain Y Y 0x 40 0000

Average Active Power 2 Offset Y Y 0x 00 0000

I2 AC Offset Y Y 0x 00 0000

Average Reactive Power 2 Offset Y Y 0x 00 0000 46 10 1110 - Reserved 47 10 1111 - Reserved 48 11 0000 - Reserved 49 11 0001 Epsilon Ratio of Line to Sample Frequency N Y 0x 01 999A 50* 11 0010 Ichan

LEVEL

Automatic Channel Select Level Y Y 0x 82 8F5C

DSP3HOST3Default

CS5480

DS980F3 33

51** 11 0011 SampleCount Sample Count N Y 0x 00 0FA0 52 11 0100 - Reserved 53 11 0101 - Reserved 54* 11 0110 T 55* 11 0111 T 56* 11 1000 P 57 11 1001 T

GAIN

OFF

MIN

SETTLE

58* 11 1010 Load 59* 11 1011 VF

RMS

60* 11 1100 SYS

(IRMS

MIN

GAIN

Temperature Gain Y Y 0x 06 B716 Temperature Offset Y Y 0x D5 3998

) Channel Select Minimum Amplitude Y Y 0x 00 624D

MIN

Filter Settling Time to Conv. Startup Y Y 0x 00 001E No Load Threshold Y Y 0x 00 0000 Voltage Fixed RMS Reference Y Y 0x 5A 8279

System Gain N Y 0x 50 0000 61 11 1101 Time System Time (in samples) N Y 0x 00 0000 62 11 1110 - Reserved 63 11 1111 - Reserved -

Notes: (1) Warning: Do not write to unpublished or reserved register locations.

(2) * Registers with checksum protection.

** When setting the AVG_MODE bit (AVG_MODE = ‘1’) in the Config2 register, the device will

use the Line-cycle Synchronized Averaging mode and the CycleCount register will be included in the checksum. Otherwise the SampleCount register will be included.

(3) Registers that can be set to write protect from DSP and/or HOST.

CS5480

34 DS980F3

6.4 Software Registers Summary (Page 17)

Address2RA[5:0] Name Description

0* 00 0000 V1Sag 1* 00 0001 V1Sag

DUR

LEVEL

V1 Sag Duration Y Y 0x 00 0000

V1 Sag Level Y Y 0x 00 0000 2 00 0010 - Reserved 3 00 0011 - Reserved 4* 00 0100 I1Over 5* 00 0101 I1Over

DUR

LEVEL

I1 Overcurrent Duration Y Y 0x 00 0000

I1 Overcurrent Level Y Y 0x 7F FFFF 6 00 0110 - Reserved 7 00 0111 - Reserved 8* 00 1000 V2Sag 9* 00 1001 V2Sag

DUR

LEVEL

V2 Sag Duration Y Y 0x 00 0000

V2 Sag Level Y Y 0x 00 0000 10 00 1010 - Reserved 11 00 1011 - Reserved 12* 00 1100 I2Over 13* 00 1101 I2Over

DUR

LEVEL

I2 Overcurrent Duration Y Y 0x 00 0000

I2 Overcurrent Level Y Y 0x 7F FFFF 14 00 1110 - Reserved 15 00 1111 - Reserved 16 01 0000 - Reserved 17 01 0001 - Reserved 18 01 0010 - Reserved 19 01 0011 - Reserved 20 01 0100 - Reserved 21 01 0101 - Reserved 22 01 0110 - Reserved 23 01 0111 - Reserved 24 01 1000 - Reserved 25 01 1001 - Reserved 26 01 1010 - Reserved 27 01 1011 - Reserved 28 01 1100 - Reserved 29 01 1101 - Reserved 30 01 1110 - Reserved 31 01 1111 - Reserved -

DSP3HOST3Default

CS5480

Notes: (1) Warning: Do not write to unpublished or reserved register locations.

(2) * Registers with checksum protection. (3) Registers that can be set to write protect from DSP and/or HOST.

DS980F3 35

CS5480

6.5 Software Registers Summary (Page 18)

Address2RA[5:0] Name Description

24* 01 1000 IZX

LEVEL

Zero-Cross Threshold for I-Channel Y Y 0x 10 0000 25 01 1001 - Reserved 26 01 1010 - Reserved 27 01 1011 - Reserved 28* 01 1100 PulseRate Energy Pulse Rate Y Y 0x 80 0000 29 01 1101 - Reserved 30 01 1110 - Reserved 31 01 1111 - Reserved 32 10 0000 - Reserved 33 10 0001 - Reserved 34 10 0010 - Reserved 35 10 0011 - Reserved 36 10 0100 - Reserved 37 10 0101 - Reserved 38 10 0110 - Reserved 39 10 0111 - Reserved 40 10 1000 - Reserved 41 10 1001 - Reserved 42 10 1010 - Reserved 43* 10 1011 INT

GAIN

Rogowski Coil Integrator Gain Y Y 0x 14 3958 44 10 1100 - Reserved 45 10 1101 - Reserved 46* 10 1110 V1Swell 47* 10 1111 V1Swell

DUR

LEVEL

V1 Swell Duration Y Y 0x 00 0000

V1 Swell Level Y Y 0x 7F FFFF 48 11 0000 - Reserved 49 11 0001 - Reserved 50* 11 0010 V2Swell 51* 11 0011 V2Swell

DUR

LEVEL

V2 Swell Duration Y Y 0x 00 0000

V2 Swell Level Y Y 0x 7F FFFF 52 11 0100 - Reserved 53 11 0101 - Reserved 54 11 0110 - Reserved 55 11 0111 - Reserved 56 11 1000 - Reserved 57 11 1001 - Reserved 58* 11 1010 VZX

LEVEL

Zero-Cross Threshold for V-Channel Y Y 0x 10 0000 59 11 1011 - Reserved 60 11 1100 - Reserved 61 11 1101 - Reserved 62** 11 1110 CycleCount Line Cycle Count N Y 0x 00 0064 63* 11 1111 Scale I-Channel Gain Calibration Scale Value Y Y 0x 4C CCCC

DSP3HOST3Default

Notes: (1) Warning: Do not write to unpublished or reserved register locations.

(2) * Registers with checksum protection.

** When setting the AVG_MODE bit (AVG_MODE = ‘1’) in the Config2 register, the device will

use the Line-cycle Synchronized Averaging mode and the CycleCount register will be included in the checksum. Otherwise the SampleCount register will be included.

(3) Registers that can be set to write protect from DSP and/or HOST.

36 DS980F3

CS5480

6.6 Register Descriptions

22. “Default” = bit states after power-on or reset

23. DO NOT write a “1” to any unpublished register bit or to a bit published as “0”.

24. DO NOT write a “0” to any bit published as “1”.

25. DO NOT write to any unpublished register address.

6.6.1 Configuration 0 (Config0) – Page 0, Address 0

23 22 21 20 19 18 17 16

1100- -- -

15 14 13 12 11 10 9 8

-0100--INT_POL

76543210

I2PGA[1] I2PGA[0] I1PGA[1] I1PGA[0] - NO_OSC IZX_CH -

Default = 0xC0 2000

[23:9] Reserved.

INT_POL Interrupt Polarity.

0 = Active low (Default) 1 = Active high

I2PGA[1:0] Select PGA gain for I2 channel.

00 = 10x gain (Default) 10 = 50x gain

I1PGA[1:0] Select PGA gain for I1 channel.

00 = 10x gain (Default) 10 = 50x gain

[3] Reserved.

NO_OSC Disable crystal oscillator (making XIN a logic-level input).

0 = Crystal oscillator enabled (Default) 1 = Crystal oscillator disabled

IZX_CH Select current channel for zero-cross detect.

0 = Selects current channel 1 for zero-cross detect (Default) 1 = Selects current channel 2 for zero-cross detect

[0] Reserved.

DS980F3 37

CS5480

6.6.2 Configuration 1 (Config1) – Page 0, Address 1

23 22 21 20 19 18 17 16

0 EPG3_ON EPG2_ON EPG1_ON 0 DO3_OD DO2_OD DO1_OD

15 14 13 12 11 10 9 8

1 1 1 0 DO3MODE[3] DO3MODE[2] DO3MODE[1] DO3MODE[0]

76543210

DO2MODE[3] DO2MODE[2] DO2MODE[1] DO2MODE[0] DO1MODE[3] DO1MODE[2] DO1MODE[1] DO1MODE[0]

Default = 0x00 EEEE

[23] Reserved.

EPG3_ON Enable EPG3 block.

0 = Disable energy pulse generation block 3 (Default) 1 = Enable energy pulse generation block 3

EPG2_ON Enable EPG2 block.

0 = Disable energy pulse generation block 2 (Default) 1 = Enable energy pulse generation block 2

EPG1_ON Enable EPG1 block.

0 = Disable energy pulse generation block 1 (Default) 1 = Enable energy pulse generation block 1

[19] Reserved.

DO3_OD Allow the DO3 pin to be an open-drain output.

0 = Normal output (Default) 1 = Open-drain output

DO2_OD Allow the DO2 pin to be an open-drain output.

0 = Normal output (Default) 1 = Open-drain output

DO1_OD Allow the DO1 pin to be an open-drain output.

0 = Normal output (Default) 1 = Open-drain output

[15:12] Reserved.

DO3MODE[3:0] Output control for DO3 pin.

0000 = Energy pulse generation block 1 (EPG1) output 0001 = Energy pulse generation block 2 (EPG2) output 0010 = Energy pulse generation block 3 (EPG3) output 0011 = Reserved 0100 = P1 sign 0101 = P2 sign 0110 = P 0111 = Q1 sign 1000 = Q2 sign 1001 = Q 1010 = Reserved 1011 = V1/V2 zero-crossing 1100 = I1/ I2 zero-crossing 1101 = Reserved 1110 = Hi-Z, pin not driven (Default) 1111 = Interrupt

SUM

sign

38 DS980F3

DO2MODE[3:0] Output control for DO2 pin.

SUM

sign 0111 = Q1 sign 1000 = Q2 sign 1001 = Q

SUM

sign 1010 = Reserved 1011 = V1/V2 zero-crossing 1100 = I1/ I2 zero-crossing 1101 = Reserved 1110 = Hi-Z, pin not driven (Default) 1111 = Interrupt

DO1MODE[3:0] Output control for DO1 pin.

SUM

sign 0111 = Q1 sign 1000 = Q2 sign 1001 = Q

SUM

sign 1010 = Reserved 1011 = V1/V2 zero-crossing 1100 = I1/I2 zero-crossing 1101 = Reserved 1110 = Hi-Z, pin not driven (Default) 1111 = Interrupt

CS5480

DS980F3 39

CS5480

6.6.3 Configuration 2 (Config2) – Page 16, Address 0

23 22 21 20 19 18 17 16

VFIX POS ICHAN IHOLD IVSP MCFG[1] MCFG[0] -

15 14 13 12 11 10 9 8

- APCM - ZX_LPF AVG_MODE REG_CSUM_OFF AFC I2FLT[1]

76543 2 10

I2FLT[0] V2FLT[1] V2FLT[0] I1FLT[1] I1FLT[0] V1FLT[1] V1FLT[0] IIR_OFF

Default = 0x00 0200

VFIX Use internal RMS voltage reference instead of voltage input for average active power.

0 = Use voltage input. (Default) 1 = Use internal RMS voltage reference (VF

POS Positive energy only. Suppress negative values in P1

value is calculated, a zero result will be stored. 0 = Positive and negative energy (Default) 1 = Positive energy only

ICHAN Chooses which current channel is used for the P

Applicable only when MCFG[1:0] = 00 and IHOLD = 1. 0 = P 1 = P

SUM

, Q , Q

SUM

, and S , and S

registers are driven by current channel 1 (P1) (Default)

SUM

registers are driven by current channel 2 (P2).

SUM

IHOLD IHOLD suspends automatic channel selection for total power calculations. Applicable

only when MCFG[1:0] = 00.

0 = Energy channel selected automatically by magnitude compare and on IVSP bit (Default) 1 = Energy channel selected by user and depend on ICHAN configuration

Refer to Channel Select Level and Channel Select (Ichan

IVSP Use I

)

and P

LEVEL

results instead of P

RMS

MIN

(IRMS

) for the magnitudes compared.

MIN

for automatic energy channel selection. Applicable

AVG

only when MCFG[1:0] = 00 and IHOLD = 0. 0 = Use P1 1 = Use I1

AVG

RMS

and P2

and I2

instead of I1

AVG

instead of P1

RMS

AVG

MCFG[1:0] Meter Configuration bits are used to control how the meter interprets the current

channels when calculating total power — independently or collectively. 00 = 1V, 1I + Neutral mode;

SUM

=P1

AVG

or P2

(Default) 01 = 1V, 2I mode;

SUM

= (P1

AVG

+P2

AVG

)/2, Q

10 = Reserved 11 = Reserved

[16:15] Reserved.

APCM Selects the apparent power calculation method.

0 = Vx

1 = SQRT(P

RMS

x Ix

AVG

RMS

+ Q

(Default)

AVG

)

[13] Reserved.

ZX_LPF Enable LPF in zero-cross detect.

0 = LPF disabled (Default) 1 = LPF enabled

AVG_MODE Select averaging mode for low-rate calculations.

0 = Use SampleCount (Default) 1 = Use CycleCount

RMS

and I2

and P2

AVG,QSUM

=(Q1

SUM

AVG

, Q

and P2

, S

SUM

. If a negative

AVG

registers.

SUM

Minimum Amplitude registers

(Default)

RMS

AVG

=Q1

+Q2

AVG

)/2, S

or Q2

SUM

AVG,SSUM

=(S1+S2)/2

=S1orS2

40 DS980F3

CS5480

REG_CSUM_OFF Disable checksum on critical registers.

0 = Enable checksum on critical registers (Default) 1 = Disable checksum on critical registers

AFC Enables automatic line frequency measurement which sets Epsilon every time a new

line frequency measurement completes. Epsilon is used to control the gain of 90-degree phase shift integrator used in quadrature power calculations. 0 = Disable automatic line frequency measurement 1 = Enable automatic line frequency measurement (Default)

I2FLT[1:0] Filter enable for current channel 2.

00 = No filter (Default) 01 = High-pass filter (HPF) on current channel 2 10 = Phase-matching filter (PMF) on current channel 2 11 = Rogowski coil integrator (INT) on current channel 2

V2FLT[1:0] Filter enable for voltage channel 2.

00 = No filter (Default) 01 = High-pass filter (HPF) on voltage channel 2 10 = Phase-matching filter (PMF) on voltage channel 2 11 = Reserved

I1FLT[1:0] Filter enable for current channel 1.

00 = No filter (Default) 01 = High-pass filter (HPF) on current channel 1 10 = Phase-matching filter (PMF) on current channel 1 11 = Rogowski coil integrator (INT) on current channel 1

V1FLT[1:0] Filter enable for voltage channel 1.

00 = No filter (Default) 01 = High-pass filter (HPF) on voltage channel 1 10 = Phase-matching filter (PMF) on voltage channel 1 11 = Reserved

IIR_OFF Bypass IIR filter.

0 = Do not bypass IIR filter (Default) 1 = Bypass IIR filter

DS980F3 41

CS5480

6.6.4 Phase Compensation (PC) – Page 0, Address 5

23 22 21 20 19 18 17 16

CPCC2[1] CPCC2[0] CPCC1[1] CPCC1[0] - - FPCC2[8] FPCC2[7]

15 14 13 12 11 10 9 8

FPCC2[6] FPCC2[5] FPCC2[4] FPCC2[3] FPCC2[2] FPCC2[1] FPCC2[0] FPCC1[8]

76543210

FPCC1[7] FPCC1[6] FPCC1[5] FPCC1[4] FPCC1[3] FPCC1[2] FPCC1[1] FPCC1[0]

Default = 0x00 0000

CPCC2[1:0] Coarse phase compensation control for I2 and V2.

00 = No extra delay 01 = 1 OWR delay in current channel 2 10 = 1 OWR delay in voltage channel 2 11 = 2 OWR delay in voltage channel 2

CPCC1[1:0] Coarse phase compensation control for I1 and V1.

00 = No extra delay 01 = 1 OWR delay in current channel 1 10 = 1 OWR delay in voltage channel 1 11 = 2 OWR delay in voltage channel 1

[19:18] Reserved.

FPCC2[8:0] Fine phase compensation control for I2 and V2.

Sets a delay in current, relative to voltage. Resolution: 0.008789° at 50Hz and 0.010547° at 60Hz (OWR = 4000)

FPCC1[8:0] Fine phase compensation control for I1 and V1.

Sets a delay in current, relative to voltage. Resolution: 0.008789° at 50Hz and 0.010547° at 60Hz (OWR = 4000)

6.6.5 UART Control (SerialCtrl) – Page 0, Address 7

23 22 21 20 19 18 17 16

- - - - - RX_PU_OFF RX_CSUM_OFF -

15 14 13 12 11 10 9 8

BR[15] BR[14] BR[13] BR[12] BR[11] BR[10] BR[9] BR[8]

765432 10

BR[7] BR[6] BR[5] BR[4] BR[3] BR[2] BR[1] BR[0]

Default = 0x02 004D

[23:19] Reserved.

RX_PU_OFF Disable the pull-up resistor on the RX input pin.

0 = Pull-up resistor enabled (Default) 1 = Pull-up resistor disabled

RX_CSUM_OFF Disable the checksum on serial port data.

0 = Enable checksum 1 = Disable checksum (Default)

[16] Reserved.

BR[15:0] Baud rate (serial bit rate).

BR[15:0] = Baud Ratex524288/MCLK

42 DS980F3

CS5480

6.6.6 Pulse Output Width (PulseWidth) – Page 0, Address 8

23 22 21 20 19 18 17 16

- - - - FREQ_RNG[3] FREQ_RNG[2] FREQ_RNG[1] FREQ_RNG[0]

15 14 13 12 11 10 9 8

PW[15] PW[14] PW[13] PW[12] PW[11] PW[10] PW[9] PW[8]

76543210

PW[7] PW[6] PW[5] PW[4] PW[3] PW[2] PW[1] PW[0]

Default = 0x00 0001 (265.6µs at OWR = 4 kHz)

PulseWidth sets the energy pulse frequency range and the duration of energy pulses.

The actual pulse duration is 250 µs plus the contents of PulseWidth divided by 64,000. PulseWidth is an integer in the range of 1 to 65,535.

[23:20] Reserved.

FREQ_RNG[3:0] Energy pulse (PulseRate) frequency range for 0.1% resolution.

0000 = Freq. range: 2 kHz – 0.238 Hz (Default) 0001 = Freq. range: 1kHz – 0.1192 Hz 0010 = Freq. range: 500 Hz – 0.0596 Hz 0011 = Freq. range: 250 Hz – 0.0298Hz 0100 = Freq. range: 125 Hz – 0.0149 Hz 0101 = Freq. range: 62.5Hz– 0.00745Hz 0110 = Freq. range: 31.25Hz – 0.003725Hz 0111 = Freq. range: 15.625Hz – 0.0018626Hz 1000 = Freq. range: 7.8125Hz – 0.000931323Hz 1001 = Freq. range: 3.90625Hz– 0.000465661Hz 1010 = Reserved

...

1111 = Reserved

PW[15:0] Energy Pulse Width.

6.6.7 Zero crossing Number (ZX

) – Page 0, Address 55

NUM

MSB LSB

.....

Default = 0x00 0064 (100)

is the number of zero crossings used for line frequency measurement. It is an integer in the range of

NUM

1 to 8,388,607. Zero should not be used.

6.6.8 Energy Pulse Rate (PulseRate) – Page 18, Address 28

MSB LSB

)2-12

-(2

Default= 0x80 0000

PulseRate sets the full-scale frequency for the energy pulse outputs.

For a 4kHz OWR rate, the maximum pulse rate is 2 kHz. This is a two's complement value in the range of

-1value1, with the binary point to the left of the MSB.

Refer to section 5.5 Meter Configuration Modes on page 23 for more information.

DS980F3 43

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

-23

CS5480

6.6.9 Pulse Output Control (PulseCtrl) – Page 0, Address 9

23 22 21 20 19 18 17 16

--------

15 14 13 12 11 10 9 8

- - - - EPG3IN[3] EPG3IN[2] EPG3IN[1] EPG3IN[0]

76543210

EPG2IN[3] EPG2IN[2] EPG2IN[1] EPG2IN[0] EPG1IN[3] EPG1IN[2] EPG1IN[1] EPG1IN[0]

Default = 0x00 0000

This register controls the input to the energy pulse generation block (EPGx).

[23:12] Reserved.

EPGxIN[3:0] Selects the input to the energy pulse generation block (EPGx).

0000 = P1 0001 = P2 0010 = P 0011 = Q1 0100 = Q2 0101 = Q 0110 = S1 0111 = S2 1000 = S 1001 = Unused

...

1111 = Unused

AVG

SUM

AVG

SUM

(Default)

6.6.10 Register Lock Control (RegLock) – Page 0, Address 34

23 22 21 20 19 18 17 16

--------

15 14 13 12 11 10 9 8

- - - DSP_LCK[4] DSP_LCK[3] DSP_LCK[2] DSP_LCK[1] DSP_LCK[0]

76543210

- - - HOST_LCK[4] HOST_LCK[3] HOST_LCK[2] HOST_LCK[1] HOST_LCK[0]

Default = 0x00 0000

[23:13] Reserved.

DSP_LCK[4:0] DSP_LCK[4:0] = 0x16 sets the DSP lockable registers to be write protected from the

CS5480 internal calculation engine. Writing 0x09 unlocks the registers.

[7:5] Reserved.

HOST_LCK[4:0] HOST_LCK[4:0] = 0x16 sets all the registers except RegLock, Status0, Status1, and

Status2 to be write protected from the serial interface. Writing 0x09 unlocks the registers.

44 DS980F3

CS5480

6.6.11 Phase Sequence Detection and Control (PSDC) – Page 0, Address 48

23 22 21 20 19 18 17 16

DONE PSCNT[6] PSCNT[5] PSCNT[4] PSCNT[3] PSCNT[2] PSCNT[1] PSCNT[0]

15 14 13 12 11 10 9 8

------ --

765432 10

- - DIR CODE[4] CODE[3] CODE[2] CODE[1] CODE[0]

Default = 0x00 0000

DONE Indicates valid count values reside in PSCNT[6:0].

0 = Invalid values in PSCNT[6:0]. (Default) 1 = Valid values in PSCNT[6:0].

PSCNT[6:0] Registers the number of OWR samples from the start time to the time when the next

zero crossing is detected.

[15:6] Reserved.

DIR Set the zero-crossing edge direction which will stop PSCNT count.

0 = Stop count at negative to positive zero-crossing - Rising Edge. (Default) 1 = Stop count at positive to negative zero-crossing - Falling Edge.

CODE[4:0] Write 10110 to this location to enable the phase sequence detection.

6.6.12 Checksum of Critical Registers (RegChk) – Page 16, Address 1

MSB LSB

.....

Default = 0x00 0000

This register contains the checksum of critical registers.

DS980F3 45

CS5480

6.6.13 Interrupt Status (Status0) – Page 0, Address 23

23 22 21 20 19 18 17 16

DRDY CRDY WOF - - MIPS V2SWELL V1SWELL

15 14 13 12 11 10 9 8

P2OR P1OR I2OR I1OR V2OR V1OR I2OC I1OC

76543 2 10

V2SAG V1SAG TUP FUP IC RX_CSUM_ERR -

Default = 0x80 0000

The Status0 register indicates a variety of conditions within the chip.

Writing a one to a Status0 register bit will clear that bit. Writing a ‘0’ to any bit has no effect.

DRDY Data Ready.

During conversion, this bit indicates that low-rate results have been updated. It indicates completion of other host instruction and the reset sequence.

CRDY Conversion Ready.

Indicates that sample rate (output word rate) results have been updated.

WOF Watchdog timer overflow.

[20:19] Reserved.

MIPS MIPS overflow.

Sets when the calculation engine has not completed processing a sample before the next one arrives.

V2SWELL (V1SWELL) V2 (V1) swell event detected.

P2OR (P1OR) Power out of range.

Sets when the measured power would cause the P2 (P1) register to overflow.

I2OR (I1OR) Power out of range.

Sets when the measured current would cause the I2 (I1) register to overflow.

V2OR (V1OR) Voltage out of range.

Sets when the measured current would cause the V2 (V1) register to overflow.

I2OC (I1OC) I2 (I1) overcurrent.

V2SAG (V1SAG) V2 (V1) sag event detected.

TUP Temperature updated.

Indicates when the Temperature register (T) has been updated.

FUP Frequency updated.

Indicates the Epsilon register has been updated.

IC Invalid command has been received.

RX_CSUM_ERR Received data checksum error.

Sets to ‘1’ automatically if checksum error is detected on serial port received data.

[1] Reserved.

RX_TO SDI/RX time out.

Sets to ‘1’ automatically when SDI/RX time out occurs.

RX_TO

46 DS980F3

CS5480

6.6.14 Interrupt Mask (Mask) – Page 0, Address 3

23 22 21 20 19 18 17 16

DRDY CRDY WOF - - MIPS V2SWELL V1SWELL

15 14 13 12 11 10 9 8

P2OR P1OR I2OR I1OR V2OR V1OR I2OC I1OC

76543 2 10

V2SAG V1SAG TUP FUP IC RX_CSUM_ERR -

Default = 0x00 0000

The Mask register is used to control the activation of the INT the corresponding Status0 register bit to activate the INT

pin. Writing a '1' to a Mask register bit will allow

pin when set.

[23:0] Enable / disable (mask) interrupts.

0 = Interrupt disabled (Default) 1 = Interrupt enabled

6.6.15 Chip Status 1 (Status1) – Page 0, Address 24

23 22 21 20 19 18 17 16

--------

15 14 13 12 11 10 9 8

LCOM[7] LCOM[6] LCOM[5] LCOM[4] LCOM[3] LCOM[2] LCOM[1] LCOM[0]

76543210

- - - - TOD VOD I2OD I1OD

RX_TO

Default = 0x80 1800

This register indicates a variety of conditions within the chip.

[23:16] Reserved.

LCOM[7:0] Indicates the value of the last serial command executed.

[7:4] Reserved.

TOD Modulator oscillation has been detected in the temperature ADC.

VOD Modulator oscillation has been detected in the voltage ADC.

I2OD (I1OD) Modulator oscillation has been detected in the current2 (current1) ADC.

DS980F3 47

CS5480

6.6.16 Chip Status 2 (Status2) – Page 0, Address 25

23 22 21 20 19 18 17 16

--------

15 14 13 12 11 10 9 8

--------

76543210

- - QSUM_SIGN Q2_SIGN Q1_SIGN PSUM_SIGN P2_SIGN P1_SIGN

Default = 0x00 0000

This register indicates a variety of conditions within the chip.

[23:6] Reserved.

QSUM_SIGN Indicates the sign of the value contained in Q

0 = positive value 1 = negative value

Q2_SIGN Indicates the sign of the value contained in Q2

0 = positive value 1 = negative value

Q1_SIGN Indicates the sign of the value contained in Q1

0 = positive value 1 = negative value

PSUM_SIGN Indicates the sign of the value contained in P

0 = positive value 1 = negative value

P2_SIGN Indicates the sign of the value contained in P2

0 = positive value 1 = negative value

P1_SIGN Indicates the sign of the value contained in P1

0 = positive value 1 = negative value

SUM

AVG

SUM

AVG

6.6.17 Line to Sample Frequency Ratio (Epsilon) – Page 16, Address 49

MSB LSB

-(2

)2-12

Default = 0x01 999A (0.0125 or 50Hz / 4.0 kHz)

Epsilon is the ratio of the input line frequency to the OWR.

It can either be written by the application program or calculated automatically from the line frequency (from the voltage channel 1 input) using the AFC bit in the Config2 register. It is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB. Negative values are not used.

48 DS980F3

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

-23

CS5480

6.6.18 Automatic Channel Select Level (Ichan

) – Page 16, Address 50

LEVEL

MSB LSB

-1

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x82 8F5C (1.02 or 2% minimum difference)

Sets the hysteresis level for automatic energy channel selection.

The channel select level register sets the hysteresis level for automatic energy channel selection. If the most-positive value of P1 least-positive value, and is also greater than Ichan

AVG

and P2

AVG

(I1

RMS

and I2

MIN

) is greater than Ichan

RMS

multiplied by the

LEVEL

, the channel associated with the most-positive value

will be used. If not, the previous channel selection will remain. The value in this register is an unsigned fixed-point value in the range of 0value2.0, with the binary point

to the right of the MSB. A value of 1.0 or less indicates no hysteresis will be used.

6.6.19 Current Channel Minimum Amplitude (P

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

MIN

-7

(IRMS

.....

)) – Page 16, Address 56

MIN

-17

-18

-19

-20

-21

-22

Default = 0x00 624D (0.003)

Sets the minimum level for automatic energy channel selection.

The P itive values of P1

MIN

(IRMS

) register sets the minimum level for automatic energy channel selection. If the most-pos-

MIN

AVG

(or I1

) register and P2

RMS

AVG

(or I2

) register is less than P

RMS

MIN

(IRMS

), the pre-

MIN

vious channel selection will remain in use. It is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

Negative values are not used.

-23

6.6.20 No Load Threshold (Load

) – Page 16, Address 58

MIN

MSB LSB

)2-12

-(2

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

Load

When the magnitudes of P the magnitude of S

Load

is used to set the no-load threshold for the anti-creep function.

MIN

and Q

SUM

is less than Load

SUM

is a two’s complement value in the range of -1.0value 1.0, with the binary point to the right of the

MIN

are less than Load

SUM

, S

MIN

is forced to zero.

SUM

MIN

, P

SUM

and Q

are forced to zero. When

SUM

MSB. Negative values are not used.

-23

DS980F3 49

CS5480

6.6.21 Voltage Fixed RMS Reference (VF

) – Page 16, Address 59

RMS

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x5A 8279 (0.7071068)

The VF

RMS

the application program. The application may choose to set the VFIX bit in the Config2 register to force full-scale energy accumulation at the VF

RMS

level.

This register holds two's complement value in the range of 0.0  value <1.0, with the binary point to the right of the MSB. Negative values are not used.

6.6.22 Sample Count (SampleCount) – Page 16, Address 51

MSB LSB

.....

Default = 0x00 0FA0 (4000)

Determines the number of OWR samples to use in calculating low-rate results.

SampleCount (N) is an integer in the range of 100 to 8,388,607. Values less than 100 should not be used.

6.6.23 Cycle Count (CycleCount) – Page 18, Address 62

-23

MSB LSB

.....

Default = 0x00 0064 (100)

Determines the number of half-line cycles to use in calculating low-rate results when the CS5480 is in Line-cycle Synchronized Averaging mode.

CycleCount is an integer in the range of 1 to 8,388,607. Zero should not be used.

6.6.24 Filter Settling Time for Conversion Startup (T

SETTLE

MSB LSB

) – Page 16, Address 57

.....

Default = 0x00 001E (30)

Sets the number of OWR samples that will be used to allow filters to settle at the beginning of Conversion and Calibration commands.

This is an integer in the range of 0 to 16,777,215 samples.

50 DS980F3

CS5480

6.6.25 System Gain (Sys

) – Page 16, Address 60

GAIN

MSB LSB

-(21)202

-1

-2

-3

-4

-5

-6

.....

-16

-17

-18

-19

-20

-21

Default = 0x50 0000 (1.25)

System Gain (Sys

By default, Sys

GAIN

) is applied to all channels.

GAIN

= 1.25, but can be finely adjusted to compensate for voltage reference error. It is a two's

complement value in the range of -2.0value2.0, with the binary point to the right of the second MSB. Values should be kept within 5% of 1.25.

6.6.26 Rogowski Coil Integrator Gain (Int

MSB LSB

-(2

)2-12

-2

-3

-4

-5

) – Page 18, Address 43

GAIN

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x14 3958

Gain for the Rogowski coil integrator. This must be programmed accordingly for 50Hz and 60Hz (0.158 for 50Hz, 0.1875 for 60Hz).

This is a two's complement value in the range of -1.0value 1.0, with the binary point to the right of the MSB. Negative values are not used.

-22

-23

6.6.27 System Time (Time) – Page 16, Address 61

MSB LSB

6.6.28 Voltage 1 Sag Duration (V1Sag

MSB LSB

.....

Default = 0x00 0000

System Time (Time) is measured in OWR samples.

This is an unsigned integer in the range of 0 to 16,777,215 samples. At OWR = 4.0 kHz, OWR will overflow every 1 hour, 9 minutes, and 54 seconds. Time can be used by the application to manage real-time events.

) – Page 17, Address 0

DUR

.....

Default = 0x00 0000

Voltage 1 Sag Duration, V1Sag

, determines the count of OWR samples utilized to determine a sag event.

DUR

These are integers in the range of 0 to 8,388,607 samples. A value of zero disables the feature.

DS980F3 51

CS5480

6.6.29 Voltage 1 Sag Level (V1Sag

) – Page 17, Address 1

LEVEL

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

Voltage 1 Sag Level, V1Sag

, establishes a threshold at which a sag event is triggered.

LEVEL

This is a two's complement value in the range of -1.0value 1.0, with the binary point to the right of the MSB. Negative values are not used.

6.6.30 Current 1 Overcurrent Duration (I1Over

MSB LSB

) – Page 17, Address 4

DUR

.....

Default = 0x00 0000

Current 1 Overcurrent Duration, I1Over

, determines the count of OWR samples utilized to determine an

DUR

overcurrent event.

This integer is in the range of 0 to 8,388,607 samples. A value of zero disables the feature.

6.6.31 Current 1 Overcurrent Level (I1Over

) – Page 17, Address 5

LEVEL

-23

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x7F FFFF

Current 1 Overcurrent Level, I1Over

, establishes a threshold at which an overcurrent event is triggered.

LEVEL

This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB. Negative values are not used.

6.6.32 Voltage 2 Sag Duration (V2Sag

MSB LSB

) – Page 17, Address 8

DUR

.....

Default = 0x00 0000

Voltage 2 Sag Duration, V2Sag

, determines the count of OWR samples utilized to determine a sag event.

DUR

These are integers in the range of 0 to 8,388,607 samples. A value of zero disables the feature.

6.6.33 Voltage 2 Sag Level (V2Sag

MSB LSB

-(20)2-12

-2

-3

-4

-5

) – Page 17, Address 9

LEVEL

-6

-7

.....

-17

-18

-19

-20

-21

-22

-23

Default = 0x00 0000

Voltage 2 Sag Level, V2Sag

, establishes a threshold at which a sag event is triggered.

LEVEL

This is a two’s complement value in the range of -1.0  value1.0, with the binary point to the right of the MSB. Negative values are not used.

52 DS980F3

CS5480

6.6.34 Current 2 Overcurrent Duration (I2Over

) – Page 17, Address 12

DUR

MSB LSB

.....

Default = 0x00 0000

Current 2 Overcurrent Duration, I2Over

, determines the count of OWR samples utilized to determine an

DUR

overcurrent event.

These are integers in the range of 0 to 8,388,607 samples. A value of zero disables the feature.

6.6.35 Current 2 Overcurrent Level (I2Over

MSB LSB

-(2

)2-12

-2

-3

-4

-5

-6

) – Page 17, Address 13

LEVEL

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x7F FFFF

Current 2 Overcurrent Level, I2Over

, establishes a threshold at which an overcurrent event is triggered.

LEVEL

This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB. Negative values are not used.

6.6.36 Voltage 1 Swell Duration (V1Swell

) – Page 18, Address 46

DUR

-23

MSB LSB

.....

Default = 0x00 0000

Voltage 1 Swell Duration, V1Swell

, determines the count of OWR samples utilized to determine a swell

DUR

event.

These are integers in the range of 0 to 8,388,607 samples. A value of zero disables the feature.

6.6.37 Voltage 1 Swell Level (V1Swell

MSB LSB

)2-12

-(2

-2

-3

-4

-5

) – Page 18, Address 47

LEVEL

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x7F FFFF

Voltage 1 Swell Level, V1Swell

, establishes a threshold at which a swell event is triggered.

LEVEL

This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB. Negative values are not used.

6.6.38 Voltage 2 Swell Duration (V2Swell

MSB LSB

) – Page 18, Address 50

DUR

.....

-23

Default = 0x00 0000

Voltage 2 Swell Duration, V2Swell

, determines the count of OWR samples utilized to determine a swell

DUR

event.

These are integers in the range of 0 to 8,388,607 samples. A value of zero disables the feature.

DS980F3 53

CS5480

6.6.39 Voltage 2 Swell Level (V2Swell

) – Page 18, Address 51

LEVEL

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x7F FFFF

Voltage 2 Swell Level, V2Swell

, establishes a threshold at which a swell event is triggered.

LEVEL

This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB. Negative values are not used.

6.6.40 Instantaneous Current 1 (I1) – Page 16, Address 2

MSB LSB

-(2

)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

I1 contains instantaneous current measurements for current channel 1. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.41 Instantaneous Voltage 1 (V1) – Page 16, Address 3

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

-23

Default = 0x00 0000

V1 contains instantaneous voltage measurements for voltage channel 1. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.42 Instantaneous Active Power 1 (P1) – Page 16, Address 4

MSB LSB

)2-12

-(2

Default = 0x00 0000

P1 contains instantaneous power measurements for current and voltage channels 1.

Values in registers I1 and V1 are multiplied to generate this value. This is a two's complement value in the range of -1.0 value 1.0, with the binary point to the right of the MSB.

6.6.43 Active Power 1 (P1

MSB LSB

-(2

)2-12

Default = 0x00 0000

Instantaneous power is averaged over each low-rate interval (SampleCount samples) and then added with power offset (P1

This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

-2

OFF

-3

AVG

-4

-5

-6

) – Page 16, Address 5

-5

-6

) to compute active power (P1

-7

.....

-7

.....

AVG

-17

-18

-19

-20

-21

-22

-23

54 DS980F3

CS5480

6.6.44 RMS Current 1 (I1

) – Page 16, Address 6

RMS

MSB LSB

-1

-2

-3

-4

-5

-6

-7

-8

.....

-18

-19

-20

-21

-22

-23

Default = 0x00 0000

contains the root mean square (RMS) values of I1, calculated during each low-rate interval.

RMS

This is an unsigned value in the range of 0 value1.0, with the binary point to the left of the MSB.

6.6.45 RMS Voltage 1 (V1

MSB LSB

-1

-2

-3

-4

) – Page 16, Address 7

RMS

-5

-6

-7

-8

.....

-18

-19

-20

-21

-22

-23

Default = 0x00 0000

contains the root mean square (RMS) value of V1, calculated during each low-rate interval.

RMS

This is an unsigned value in the range of 0 value1.0, with the binary point to the left of the MSB.

6.6.46 Instantaneous Current 2 (I2) – Page 16, Address 8

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

-24

-23

Default = 0x00 0000

I2 contains instantaneous current measurements for current channel 2. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.47 Instantaneous Voltage 2 (V2) – Page 16, Address 9

MSB LSB

)2-12

-(2

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

V2 contains instantaneous voltage measurements for voltage channel 1. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.48 Instantaneous Active Power 2 (P2) – Page 16, Address 10

MSB LSB

-(2

)2-12

Default = 0x00 0000

P2 contains instantaneous power measurements for current and voltage channels 2.

Values in registers I2 and V are multiplied to generate this value. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

-23

DS980F3 55

CS5480

6.6.49 Active Power 2 (P2

) – Page 16, Address 11

AVG

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

Instantaneous power is averaged over each low-rate interval (SampleCount samples) to compute active power (P2

AVG

This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.50 RMS Current 2 (I2

MSB LSB

-1

-2

-3

-4

) – Page 16, Address 12

RMS

-5

-6

-7

-8

.....

-18

-19

-20

-21

-22

-23

Default = 0x00 0000

contains the root mean square (RMS) value of I2, calculated during each low-rate interval.

RMS

This is an unsigned value in the range of 0 value1.0, with the binary point to the left of the MSB.

6.6.51 RMS Voltage 2 (V2

MSB LSB

-1

-2

-3

-4

) – Page 16, Address 13

RMS

-5

-6

-7

-8

.....

-18

-19

-20

-21

-22

-23

-24

Default = 0x00 0000

contains the root mean square (RMS) value of V2, calculated during each low-rate interval.

RMS

This is an unsigned value in the range of 0 value1.0, with the binary point to the left of the MSB.

6.6.52 Reactive Power 1 (Q1

MSB LSB

)2-12

-(2

-2

-3

) – Page 16, Address 14

Avg

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

Reactive power 1 (Q1 by Q1

OFF

) is Q1 averaged over each low-rate interval (SampleCount samples) and corrected

AVG

This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.53 Instantaneous Quadrature Power 1 (Q1) – Page 16, Address 15

MSB LSB

-(2

)2-12

Default = 0x00 0000

Instantaneous quadrature power, Q1, the product of V1 shifted 90 degrees and I1. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

-23

56 DS980F3

CS5480

6.6.54 Reactive Power 2 (Q2

) – Page 16, Address 16

Avg

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

Reactive power 2 (Q2

) is Q2 averaged over each low-rate interval (SampleCount samples).

AVG

This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.55 Instantaneous Quadrature Power 2 (Q2) – Page 16, Address 17

MSB LSB

-(2

)2-12

Default = 0x00 0000

Instantaneous quadrature power, Q2, the product of V2 shifted 90 degrees and I2. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.56 Peak Current 1 (I1

MSB LSB

-(20)2-12

-2

-3

-4

PEAK

-4

-5

-6

) – Page 0, Address 37

-5

-6

-7

.....

-7

.....

-17

-18

-19

-20

-21

-22

-23

Default = 0x00 0000

Peak Current 1 (I1

) contains the value of the instantaneous current 1 sample with the greatest magnitude

PEAK

detected during the last low-rate interval. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.57 Peak Voltage 1 (V1

MSB LSB

)2-12

-(2

-2

-3

) – Page 0, Address 36

PEAK

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

Peak voltage 1 (V1

) contains the value of the instantaneous voltage 1 sample with the greatest magni-

PEAK

tude detected during the last low-rate interval. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.58 Apparent Power 1 (S1) – Page 16, Address 20

MSB LSB

-1

Default = 0x00 0000

Apparent power 1 (S1) is the product of V1 This is an unsigned value in the range of 0 value 1.0, with the binary point to the right of the MSB.

-2

-3

-4

-5

-6

RMS

-7

and I1

.....

or SQRT(P1

RMS

-17

-18

AVG

-19

+ Q1

-20

AVG

-21

-22

-23

DS980F3 57

CS5480

6.6.59 Power Factor 1 (PF1) – Page 16, Address 21

MSB LSB

-(20)2-12

-2

Default = 0x00 0000

Power factor 1 (PF1) is calculated by dividing active power 1 (P1

The sign is determined by the active power (P1 This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

-3

-4

-5

-6

-7

AVG

.....

) sign.

-17

AVG

-18

-19

-20

) by apparent power 1 (S1).

-21

-22

-23

6.6.60 Peak Current 2 (I2

) – Page 0, Address 39

PEAK

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

Peak current, I2

, contains the value of the instantaneous current 2 sample with the greatest magnitude

PEAK

detected during the last low-rate interval. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.61 Peak Voltage 2 (V2

MSB LSB

-(20)2-12

-2

-3

) – Page 0, Address 38

PEAK

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

Peak voltage, V2

, contains the value of the instantaneous voltage 2 sample with the greatest magnitude

PEAK

detected during the last low-rate interval. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.62 Apparent Power 2 (S2) – Page 16, Address 24

-23

MSB LSB

-1

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

-23

Default = 0x00 0000

Apparent power 2 (S2) is the product of V2

RMS

and I2

or SQRT(P2

RMS

AVG

+ Q2

AVG

This is an unsigned value in the range of 0 value 1.0, with the binary point to the right of the MSB.

6.6.63 Power Factor 2 (PF2) – Page 16, Address 25

MSB LSB

-(20)2-12

-2

Default = 0x00 0000

Power factor 2 (PF2) is calculated by dividing active power 2 (P2

The sign is determined by the active power (P2 This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

58 DS980F3

-3

-4

-5

-6

-7

AVG

.....

) sign.

-17

AVG

-18

-19

-20

) by apparent power 2 (S2).

-21

-22

-23

CS5480

6.6.64 Temperature (T) – Page 16, Address 27

MSB LSB

-(27)262

Default = 0x00 0000

T contains results from the on-chip temperature measurement. By default, T uses the Celsius scale, and is a two's complement value in the range of -128.0value128.0

(°C), with the binary point to the right of bit 16. Negative values are not used.

.....

-10

-11

-12

-13

-14

-15

-16

T can be rescaled by the application using the T

6.6.65 Total Active Power (P

) – Page 16, Address 29

SUM

GAIN

and T

registers.

OFF

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

SUM

=P1

AVG

+P2

or P2

if MCFG[1:0] = 01

AVG

if MCFG[1:0] = 00

AVG

This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

6.6.66 Total Apparent Power (S

MSB LSB

-1

-2

-3

-4

) – Page 16, Address 30

SUM

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

= S1+S2 if MCFG[1:0] = 01

SUM

= S1 or S2 if MCFG[1:0] = 00

SUM

This is an unsigned value in the range of 0 value 1.0, with the binary point to the right of the MSB.

-23

6.6.67 Total Reactive Power (Q

) – Page 16, Address 31

SUM

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

-23

Default = 0x00 0000

SUM

=Q1

AVG

+Q2

or Q2

if MCFG[1:0] = 01

AVG

if MCFG[1:0] = 00

AVG

This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB.

DS980F3 59

CS5480

6.6.68 DC Offset for Current (I1

DCOFF

, I2

DCOFF

) – Page 16, Address 32, 39

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

DC offset registers I1

DCOFF

and I2

are initialized to zero on reset. During DC offset calibration, selected

DCOFF

registers are written with the inverse of the DC offset measured. The application program can also write the DC offset register values. These are two's complement values in the range of -1.0value 1.0, with the binary point to the right of the MSB.

6.6.69 DC Offset for Voltage (V1

DCOFF

MSB LSB

)2-12

-(2

-2

-3

-4

, V2

DCOFF

-5

-6

) – Page 16, Address 34, 41

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

DC offset registers V1

DCOFF

and V2

are initialized to zero on reset. During DC offset calibration, select-

DCOFF

ed registers are written with the inverse of the DC offset measured. The application program can also write the DC offset register values. These are two's complement values in the range of -1.0 value 1.0, with the binary point to the right of the MSB.

6.6.70 Gain for Current (I1

GAIN

, I2

) – Page 16, Address 33, 40

GAIN

-23

MSB LSB

-1

-2

-3

-4

-5

-6

.....

-16

-17

-18

-19

-20

-21

Default = 0x40 0000 (1.0)

Gain registers I1

GAIN

and I2

are initialized to 1.0 on reset. During gain calibration, selected registers are

GAIN

written with the multiplicative inverse of the gain measured. These are unsigned, fixed-point values in the range of 0 value4.0, with the binary point to the right of the second MSB.

6.6.71 Gain for Voltage (V1

MSB LSB

-1

-2

GAIN

-3

, V2

) – Page 16, Address 35, 42

GAIN

-4

-5

-6

.....

-16

-17

-18

-19

-20

-21

Default = 0x40 0000 (1.0)

Gain registers V1

GAIN

and V2

are initialized to 1.0 on reset. During gain calibration, selected register are

GAIN

written with the multiplicative inverse of the gain measured. These are unsigned fixed-point values in the range of 0 value4.0, with the binary point to the right of the second MSB.

6.6.72 Average Active Power Offset (P1

MSB LSB

)2-12

-(2

-2

-3

-4

-5

OFF

-6

, P2

) – Page 16, Address 36, 43

OFF

-7

.....

-17

-18

-19

-20

-21

-22

-23

Default = 0x00 0000

Average Active Power offset P1

OFF

(P2

) is added to averaged power to yield P1

OFF

AVG

(P2

) register re-

AVG

sults. It can be used to reduce systematic energy errors. These are two's complement values in the range of

-1.0 value  1.0, with the binary point to the right of the MSB.

60 DS980F3

CS5480

6.6.73 Average Reactive Power Offset (Q1

OFF

, Q2

) – Page 16, Address 38, 45

OFF

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x00 0000

Average Reactive Power Offset (Q1 (Q2

) register results. It can be used to reduce systematic energy errors. These are two's complement val-

AVG

OFF

, Q2

) is added to averaged reactive power to yield Q1

OFF

AVG

ues in the range of -1.0 value  1.0, with the binary point to the right of the MSB.

6.6.74 AC Offset for Current (I1

MSB LSB

-1

-2

-3

-4

-5

ACOFF

-6

, I2

ACOFF

-7

) – Page 16, Address 37, 44

-8

.....

-18

-19

-20

-21

-22

-23

Default = 0x00 0000

AC offset registers I1

ACOFF

and I2

are initialized to zero on reset. They are used to reduce systematic

ACOFF

errors in the RMS results. These are unsigned values in the range of 0  value  1.0, with the binary point to the left of the MSB.

6.6.75 Temperature Gain (T

MSB LSB

) – Page 16, Address 54

GAIN

.....

-10

-11

-12

-13

-14

-15

-23

-24

-16

Default = 0x 06 B716

is used to scale the Temperature register (T), and is an unsigned fixed-point value in the range

GAIN

of 0.0value256.0, with the binary point to the right of bit 16.

GAIN

and T

registers. Refer to section 7.3 Tem-

OFF

perature Sensor Calibration on page 65 for more information.

6.6.76 Temperature Offset (T

MSB LSB

-(2

)262

) – Page 16, Address 55

OFF

.....

-10

-11

-12

-13

-14

-15

Default = 0x D5 3998

is used to offset the Temperature register (T), and is a two's complement value in the range of

OFF

-128.0value128.0 (°C), with the binary point to the right of bit 16.

GAIN

and T

registers. Refer to section 7.3 Tem-

OFF

perature Sensor Calibration on page 65 for more information.

-16

DS980F3 61

CS5480

6.6.77 Calibration Scale (Scale) – Page18, Address 63

MSB LSB

-(20)2-12

-2

Default = 0x4C CCCC (0.6)

The Scale register is used in the gain calibration to set the level of calibrated results of I-channel RMS. During gain calibration, the Ix register. This is a two's complement value in the range of -1.0value1.0, with the binary point to the right of the MSB. Negative values are not used.

-3

RMS

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

results register is divided into the Scale register. The quotient is put into the Ix

-22

-23

GAIN

6.6.78 V-channel Zero-crossing Threshold (VZX

) – Page 18, Address 58

LEVEL

MSB LSB

)2-12

-(2

-2

-3

-4

-5

-6

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x10 0000 (0.125)

VZX function. This is a two's complement value in the range of -1.0

is the level that the peak instantaneous voltage must exceed for the zero-crossing detection to

LEVEL

value<1.0, with the binary point to the right of

the MSB. Negative values are not used.

6.6.79 I-channel Zero-crossing Threshold (IZX

MSB LSB

-(20)2-12

-2

-3

-4

-5

-6

) – Page 18, Address 24

LEVEL

-7

.....

-17

-18

-19

-20

-21

-22

Default = 0x10 0000 (0.125)

IZX tion. This is a two's complement value in the range of -1.0

is the level that the peak instantaneous current must exceed for the zero-crossing detection to func-

LEVEL

value<1.0, with the binary point to the right of the

MSB. Negative values are not used.

-23

62 DS980F3

CS5480

RMS

, I

RMS

Registers

Modulator Filter



* Denotes readable/writable register

Applies only to the current path (I1, I2)

N



-1



RMS

-1

RMS

0.6 ( Scale

)

V*, I*, P*, Q

Registers

GAIN

, V

GAIN

Registers

DCOFF

, V

DCOFF

Registers

ACOFF

Figure 25. Calibration Data Flow

7. SYSTEM CALIBRATION

Component tolerances, residual ADC offset, and system noise require a meter to be calibrated before it meets a specific accuracy requirement. The CS5480 provides an on-chip calibration algorithm to operate the system calibration quickly and easily. Benefiting from the excellent linearity and low noise level of the CS5480, normally a CS5480 meter only needs one calibration at a single load point to achieve accurate measurements over the full load range.

7.1 Calibration in General

The CS5480 provides DC offset and gain calibration that can be applied to the instantaneous voltage and current measurements and AC offset calibration, which can be applied to the current RMS calculation.

Since the voltage and current channels have independent offset and gain registers, offset and gain calibration can be performed on any channel independently.

The data flow of the calibration is shown in Figure 25.

Note that in Figure 25 the AC offset registers and gain registers affect the output results differently than the DC offset registers. The DC offset and gain values are applied to the voltage/current signals very early in the signal path; the DC offset register and gain register values affect all CS5480 results. This is not true for the AC offset correction. The AC offset registers only affect the results of the RMS current calculation.

The CS5480 must be operating in its active state and ready to accept valid commands. Refer to section 6.1.2

Instructions on page 29 for different calibration

commands. The value in the SampleCount register determines the number (N) of OWR samples that are averaged during a calibration. The calibration

procedure takes the time of N +T

SETTLE

OWR samples. As N is increased, the calibration takes more time but the accuracy of calibration results tends to increase.

The DRDY bit in the Status0 register will be set at the completion of calibration commands. If an overflow occurs during calibration, other Status0 bits may be set as well.

7.1.1 Offset Calibration

During offset calibrations, no line voltage or current should be applied to the meter. In other words, the differential signal on voltage inputs VIN± or current inputs IIN1± (IIN2±) of the CS5480 should be 0V.

7.1.1.1 DC Offset Calibration

The DC offset calibration command measures and averages DC values read on specified voltage or current channels at zero input and stores the inverse result in the associated offset registers. This DC offset will be added to instantaneous measurements in subsequent conversions, removing the offset.

The gain register for the channel being calibrated should be set to 1.0 prior to performing DC offset calibration.

DC offset calibration is not required if the high-pass filter is enabled on that channel because the DC component will be removed by the high-pass filter.

7.1.1.2 Current Channel AC Offset Calibration

The AC offset calibration command measures the residual RMS value on the current channel at zero input and stores the squared result in the associated AC offset register. This AC offset will be subtracted from RMS measurements in subsequent conversions, removing the AC offset on the associated current channel.

DS980F3 63

CS5480

0xFFFFFF

The AC offset register for the channel being calibrated should first be cleared prior to performing the calibration. The high-pass filter should be enabled if AC offset calibration is used. It is recommended that

SETTLE

be set to 2000ms before performing an AC offset calibration. Note that the AC offset register holds the square of RMS value measured during calibration. Therefore, it can hold a maximum RMS noise of . This is the maximum RMS noise that AC offset correction can remove.

7.1.2 Gain Calibration

Prior to executing the gain calibration command, gain registers for any path to be calibrated (Vx should be set to 1.0, and T

SETTLE

should be set to 2000 ms. For gain calibration, a reference signal must be applied to the meter. During gain calibration, the voltage RMS result register (Vx and the current RMS result register (Ix

) is divided into 0.6,

RMS

into the Scale register. The quotient is put into the associated gain register. The gain calibration algorithm attempts to adjust the gain register (Vx such that the voltage RMS result register (Vx equals 0.6, and the current RMS result register (Ix equal the Scale register.

Note that for the gain calibration, there are some limitations on choosing the reference level and the Scale register value. Using a reference or a scale that is too large or too small can cause register overflow during calibration or later during normal operation. Either condition can set Status register bits I1OR (I2OR), or VOR. The maximum value that the gain register can attain is four. Using inappropriate reference levels or scale values may also cause the CS5480 to attempt to set the gain register higher than four, therefore the gain calibration result will be invalid.

The Scale register is 0.6 by default. The maximum voltage (U

Volts) and current (I

MAX

meter should be used as the reference signal level if the

Scale register is 0.6. After gain calibration, 0.6 of the Vx

RMS

(Ix

) register represents U

RMS

MAX

Amps) for the line voltage (load current); 0.36 of the

AVG

, Q

, or Sx register represents U

AVG

Watts, Vars, or VAs for the active, reactive, or apparent power.

If the calibration is performed with U Amps and I

CAL<IMAX

scaled down to 0.6× I

, the Scale register needs to be

CAL/IMAX

MAX

before performing gain calibration. After gain calibration, 0.6 of the Vx register represents U

Volts , 0.6 x I

MAX

CAL/IMAX

, Ix

GAIN

) is divided

, Ix

GAIN

RMS

Amps) of the

Volts (I

Volts and I

MAX

MAX×IMAX

CAL

RMS

of the

RMS

0.36 × I

CAL/IMAX

represents U

of the Px

MAXxICAL

, Qx

AVG

Watts, Vars, or VAs.

Amps, and

CAL

, or Sx register

AVG

7.1.3 Calibration Order

1) If the HPF option is enabled, then any DC component that may be present in the selected signal channel will be removed, and a DC offset calibration is not required. However, if the HPF option is disabled, the DC offset calibration should be performed.

When using high-pass filters, it is recommended that

the DC offset register for the corresponding channel be set to 0. Before performing DC offset calibration,

)

the DC offset register should be set to zero, and the corresponding gain register should be set to one.

2) If there is an AC offset in the Ix

calculation, the

RMS

AC offset calibration should be performed on the current channel. Before performing AC offset calibration, the AC offset register should be set to zero. It is recommended that T

) ) )

performing an AC offset calibration.

3) Perform the gain calibration.

4) If an AC offset calibration was performed (step 2),

SETTLE

be set to 2000ms before

then the AC offset may need to be adjusted to compensate for the change in gain (step 3). This can be accomplished by restoring zero to the AC offset register and then perform an AC offset calibration. The adjustment could also be done by multiplying the AC offset register value that was calculated in step 2 by the gain calculated in step 3 and updating the AC offset register with the product.

7.2 Phase Compensation

A phase compensation mechanism is provided to adjust for meter-to-meter variation in signal path delays. Phase offset between a voltage channel and its corresponding current channel can be calculated by using the power factor (PF1, PF2) register after a conversion.

1) Apply a reference voltage and current with a lagging

power factor to the meter. The reference current waveform should lag the voltage with a 60° phase shift.

2) Start continuous conversion.

3) Accumulate multiple readings of the PF1 or PF2

4) Calculate the average power factor, PF

5) Calculate phase offset = arccos(PF

avg

) - 60°.

64 DS980F3

CS5480

ymxb+=

Force Temperature (

T Register Value

Y = m • x + b

OFF

-----

GAIN

6) If the phase offset is negative, then the delay should be added only to the current channel. Otherwise, add more delay to the voltage channel than to the current channel to compensate for a positive phase offset.

Once the phase offset is known, the CPCCx and FPCCx bits for that channel are calculated and programmed in the PC register.

CPCCx bits are used if either:

• The phase offset is more than 1 output word rate

(OWR) sample.

• More delay is needed on the voltage channel.

The compensation resolution is 0.008789° at 50Hz and

0.010547° at 60Hz at an OWR of 4000Hz.

7.3 Temperature Sensor Calibration

Temperature sensor calibration involves the adjustment of two parameters: temperature gain (T temperature offset (T must be set to 1.0 (0x 01 0000), and T

). Before calibration, T

OFF

to 0.0 (0x 00 0000).

) and

GAIN

must be set

7.3.1 Temperature Offset and Gain Calibration

To obtain the optimal temperature offset (T value and temperature (T

) register value, it is

GAIN

necessary to measure the temperature (T) register at a minimum of two points (T1 and T2) across the meter operating temperature range. The two temperature points must be far enough apart to yield reasonable accuracy, for example 25

°C and 85°C. Obtain a linear

fit of these points ( ), where the slope (m) and intercept (b) can be obtained.

) register

OFF

Figure 26. T Register vs. Force Temp

OFF

and T

are calculated using the following

GAIN

equations:

DS980F3 65

CS5480

5 x 330K

CS5480

27nF

L1 L 2N

IIN1 +

IIN1 -

IIN2 +

IIN2 -

Application

Processor

RESET

GNDA GNDD

DO3

DO1

DO2

VDD A

+3.3V

0.1µF

+3 .3V

VDD D

+3.3V

VREF -

VREF +

0.1µF

27nF

½ R

BURDEN

Wh Varh

4. 096M Hz

XIN

XOUT

SSEL

Interrupt

½ R

BURDEN

½ R

BURDEN

½ R

BURDEN

MODE

VIN+

VIN-

27nF

+3.3V

LOAD LOAD

0.1 µF

10 K

+3 .3 V

1 Voltage and 2 Current

Figure 27. Typical Single-phase 3-Wire Connection

8. BASIC APPLICATION CIRCUITS

Figure 27 shows the CS5480 configured to measure power in a single-phase, 3-wire system with 1 voltage and 2 currents (1V-2I). Figure 28 shows the CS5480 configured to measure power in a single-phase, 2-wire

system with 1 voltage, 1 line current and 1 neutral current (1V-1I-1N). In these diagrams, current transformers (CTs) are used to sense the line load currents, and resistive voltage dividers are used to sense the line voltage.

66 DS980F3

CS5480

5 x 330K

CS5480

27n F

IIN1 +

IIN1 -

IIN2 -

IIN2 +

Application

Processor

RESET

GNDA GN DD

DO3

DO1

DO2

VDD A

+3.3V

0.1µF

+3 .3V

VDD D

+3.3V

VREF-

VREF+

0.1µF

27n F

½ R

BURDEN

Wh Varh

4.096MHz

XIN

XOUT

SSEL

Interrupt

½ R

BURDEN

½ R

BURDEN

½ R

BURDEN

MODE

VIN +

VIN -

27nF

+3.3V

LOAD

0. 1µF

10 K

+3 .3 V

1 Voltage , 1 Line Current,

and 1 Neutral C urrent

Figure 28. Typical Single-phase 2-Wire Connection

DS980F3 67

9. PACKAGE DIMENSIONS

24 QFN (4mmX4mm BODY with EXPOSED PAD) PACKAGE DRAWING

Notes:

1. Controlling dimensions are in millimeters.

2. Dimensions and tolerances per ASME Y14.5M.

3. This drawing conforms to JEDEC outline MO-220, variation VGGD-6 with the exception of features D2 and E2, which are per supplier designations.

4. Recommended reflow profile is per JEDEC / IPC J-STD-020.

CS5480

mm inch

Dimension MIN NOM MAX MIN NOM MAX

A 0.80 0.90 1.00 0.031 0.035 0.039 A1 0.00 0.02 0.05 0.000 0.001 0.002 A3 0.20 REF 0.008 REF

b 0.20 0.25 0.30 0.008 0.010 0.012

D 4.00 BSC 0.157 BSC D2 2.40 2.50 2.60 0.094 0.098 0.102

e 0.50 BSC 0.020 BSC

E 4.00 BSC 0.157 BSC E2 2.40 2.50 2.60 0.094 0.098 0.102

L 0.35 0.40 0.45 0.014 0.016 0.018 aaa 0.15 0.006 bbb 0.10 0.004 ddd 0.05 0.002 eee 0.08 0.003

68 DS980F3

CS5480

10. ORDERING INFORMATION

Ordering Number Container Temperature Package

CS5480-INZ Bulk

CS5480-INZR Tape & Reel

11. ENVIRONMENTAL, MANUFACTURING, AND HANDLING INFORMATION

Part Number Peak Reflow Temp MSL Rating* Max Floor Life

CS5480-INZ

260 °C 3 7 Days

* MSL (Moisture Sensitivity Level) as specified by IPC/JEDEC J-STD-020.

12. REVISION HISTORY

Revision Date Changes

PP1 APR 2012 Preliminary release.

F1 APR 2012 Edited for content and clarity.

F2 JUN 2012 Updated ordering information.

F3 MAR 2013 Clarified context.

-40 to +85 °C 24-pin QFN, Lead (Pb) Free

DS980F3 69

CS5480

Contacting Cirrus Logic Support

For all product questions and inquiries contact a Cirrus Logic Sales Representative. To find the one nearest to you go to www.cirrus.com

IMPORTANT NOTICE

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SPI is a trademark of Motorola, Inc.

70 DS980F3

Cirrus Logic CS5480 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Features

1. OVERVIEW

2. PIN DESCRIPTION

Thermal Pad

Clock Generator

Digital Pins and Serial Data I/O

Analog Inputs/Outputs

Power Supply Connections

2.1 Analog Pins

2.1.1 Voltage Input

2.1.2 Current1 and Current2 Inputs

2.1.3 Voltage Reference

2.1.4 Crystal Oscillator

2.2 Digital Pins

2.2.1 Reset Input

2.2.2 Digital Outputs

2.2.3 UART/SPI™ Serial Interface

2.2.3.1 SPI

2.2.3.2 UART

2.2.4 MODE Pin

3. CHARACTERISTICS AND SPECIFICATIONS

RECOMMENDED OPERATING CONDITIONS

POWER MEASUREMENT CHARACTERISTICS

TYPICAL LOAD PERFORMANCE

ANALOG CHARACTERISTICS

Analog Inputs (Current Channels)

Analog Inputs (Voltage Channels)

Temperature

Power Supplies

VOLTAGE REFERENCE

DIGITAL CHARACTERISTICS

Master Clock Characteristics

Filter Characteristics

Input/Output Characteristics

SWITCHING CHARACTERISTICS

Start-up

SPI Timing

UART Timing

ABSOLUTE MAXIMUM RATINGS

4. SIGNAL FLOW DESCRIPTION

4.1 Analog-to-Digital Converters

4.2 Decimation Filters

4.3 IIR Filters

4.4 Phase Compensation

4.5 DC Offset and Gain Correction

4.6 High-pass and Phase Matching Filters

4.7 Digital Integrators

4.8 Low-rate Calculations

4.8.1 Fixed Number of Samples Averaging

4.8.2 Line-cycle Synchronized Averaging

4.8.3 RMS Current and Voltage

4.8.5 Reactive Power

4.8.6 Apparent Power

4.8.7 Peak Voltage and Current

4.8.8 Power Factor

4.8.4 Active Power

4.9 Average Active Power Offset

4.10 Average Reactive Power Offset

5. FUNCTIONAL DESCRIPTION

5.1 Power-on Reset

5.2 Power Saving Modes

5.3 Zero-crossing Detection

5.4 Line Frequency Measurement

5.5 Meter Configuration Modes

5.6 Tamper Detection and Correction

5.6.1 Anti-tampering on Current

5.6.1.1 Automatic Channel Selection

5.6.1.2 Manual Channel Selection

5.6.2 Anti-tampering on Voltage

5.7 Energy Pulse Generation

5.7.1 Pulse Rate

5.7.2 Pulse Width

5.8 Voltage Sag, Voltage Swell, and Overcurrent Detection

5.9 Phase Sequence Detection

5.10 Temperature Measurement

5.11 Anti-Creep