Cirrus Logic CS5462 User Manual

CS5462

PGA

VA+

IIN+

IIN-

VIN+

VIN-

VREFIN

VREFOUT

High Pass

Filter

Voltage

Reference

RESET

Digital

Filter

High Pass

Filter

x10

Energy to

Pulse Rate

Converter

4th Order 

Modulator

2nd Order 

Modulator

Digital

Filter

x10,x50

DGND / P1

Energy

Direction

Calibration

VD+ / P7

Configuration Inputs: On-Chip Calibration,

Pulse Output Mode / Output Frequency,

HPF Option, and

Current Channel Input Range

Clock

Generator

XOUT CPUCLK

E2 / P4

E1 / P5

FOUT / P6

IGAIN CAL1FREQ CAL0

NEG/P2

XIN

Program Select

Outputs

for

Configuration

AGND

Low-cost Power/Energy IC with Pulse Output

Features

 Single-chip Power Measurement Solution  Energy Data Linearity: ±0.1% of Reading over

1000:1 Dynamic Range

 On-chip functions: Measures Energy and

Performs Energy-to-Pulse Conversions

 Meets Accuracy Spec for IEC 687/1036  On-chip System Calibration Option  High-pass Filter Option for Both I and V  2 Available Current Input Ranges  On-chip 2.5 V Reference (25 ppm/°C typ)  Pulse Outputs for Stepper Motor or Mechanical

Counter

 On-chip Energy Direction Indicator  Ground Reference Input Signals with Single

Supply

 High-frequency Output for Calibration  On-chip Power-on Reset  Power Supply Configurations:

VA+ = +5 V; AGND = 0 V; VD+ = +3.3 V to 5 V

Description

The CS5462 is a low-cost power meter solution combining two analog-to-digital convertersADCs), an energy-to-frequency converter, and energy pulse outputs on a single chip. It is designed to accurately measure and calculate energy for single-phase 2- or 3wire power metering applications with minimal external components.

Low-frequency energy outputs, E1 average real power and can be used to drive a stepper motor or a mechanical counter; the high-frequency energy output FOUT NEG

indicates negative power.

can be used for calibration; and

The CS5462 has configuration pins which allow for direct configuration of pulse output format, pulse output frequency, current channel input range, high-pass filter option, and on-chip calibration.

The CS5462 also has a power-on reset function which holds the part in reset until the supply reaches an operable level.

ORDERING INFORMATION:

See page 16.

and E2, supply

http://www.cirrus.com

APR 11

DS547F1

TABLE OF CONTENTS

1. GENERAL DESCRIPTION .......................................................................................................3

2. PIN DESCRIPTION ...................................................................................................................3

3. CHARACTERISTICS/SPECIFICATIONS ................................................................................. 5

ANALOG CHARACTERISTICS................................................................................................5

DIGITAL CHARACTERISTICS.................................................................................................7

SWITCHING CHARACTERISTICS ..........................................................................................7

ABSOLUTE MAXIMUM RATINGS ........................................................................................... 8

3.1 Theory of Operation ......................................................... .... ... ........................................... 9

3.1.1 Digital Filters ............. .... ... ... ... ....................................... ... ... .... ... ...........................9

3.1.2 Gain Calibration .................. ... ... .... ... ....................................... ... ... ... .... ... ... ... ........9

3.1.3 Energy-to-Frequency Conversion .......... .... ... ... ... .... ... ... ... ... .... ... ... ... .... .................9

4. FUNCTIONAL DESCRIPTION ...............................................................................................10

4.1 Programmable Gain Amplifier (PGA) ............................................................................... 10

4.2 Pulse-Rate Output ..................................... ... ...................................................................10

4.2.1 Stepper Motor Format. ........................................................................................10

4.2.2 Mechanical Counter Format ................................................................................ 11

4.3 Energy Direction Indicator ................................................................................................11

4.4 Internal Calibration Option ...............................................................................................11

4.5 Power-on Reset ............................ ... ... ....................................... ... ... .... ... ... ... .... ...............11

4.6 Oscillator Characteristics .................... ... .... ... ... ... .... ... ... .......................................... ... ... ...12

4.7 User Defined Settings .......................................................... ... ... ......................................12

4.8 Basic Application Circuit Configurations .......................................................................... 14

5. PACKAGE DIMENSIONS ....................................................................................................... 15

6. ORDERING INFORMATION .................................................................................................. 16

7. ENVIRONMENTAL, MANUFACTURING, & HANDLING INFORMATION ............................ 16

8. REVISIONS ............................................................................................................................. 16

CS5462

LIST OF FIGURES

Figure 1. Data Flow......................................................................................................................... 9

Figure 2. PGA Settings..................................................................................................................10

Figure 3. Pulse Output Settings ....................................................................................................10

Figure 6. Calibration Options......................................................................................................... 11

Figure 7. Power-on Reset .............................................................................................................12

Figure 8. Oscillator Connection.....................................................................................................12

Figure 9. Calibration, Frequency Select, and PGA Select ............................................................12

Figure 7. Power-on Reset .............................................................................................................13

Figure 8. Typical Connection Diagram..........................................................................................14

2 DS547F1

CS5462

VREFIN 12Voltage Reference Input

VREFOUT 11Voltage Reference Output

VIN- 10Differenti al Voltage Input

VIN+ 9Differenti al Voltage Input

DGND 8Digital Ground

FREQ 7Frequency Select

NEG / P2 6Neg Energy Indi c ator / Prog Sel 2

CAL0 5Calibrat ion Pin 0

DGND / P1 4Digital Ground / Pr og S el 1

VD+ / P7 3Positive Power Supply / P r og Se l 7

CPUCLK 2CPU Clock Output

XOUT 1Crystal Out

AGND13 Analog Ground

VA+14 Positive Analog Supply

IIN-15 Different i al Current Input

IIN+16 Different i al Current Input

IGAIN17 Gain Select

FOUT / P618 High Frequency Output / Prog Sel 6

RESET19 Reset

P320 Program Select 3

E1 / P521 Energy Output 1 / Prog Sel 5

E2 / P422 Energy Output 2 / Prog Sel 4

CAL123 Calibr ation Pin 1

XIN24 Crystal In

1. GENERAL DESCRIPTION

The CS5462 is a CMOS monolithic power measurement device with an energy computation engine. The CS5462 combines a programmable gain amplifier, two  ADC’s, system calibration, and energy-to-frequency conversion circuitry on a single chip.

The CS5462 is designed for energy measurement applications and is optimized to interface to a shunt or current transformer for current measurement, and to a resistive divider or transformer for voltage measurement. The current channel has a pro-

2. PIN DESCRIPTION

grammable gain amplifier (PGA) which provides two full-scale input level options. With a single +5 V supply on VA+/AGND, both of the CS5462’s input channels accommodate common mode + signal levels between (AGND - 0.25 V) and VA+.

The CS5462 has three pulse output pins: E1

, E2 and FOUT. E1 and E2 can be used to directly drive a mechanical counter or stepper motor, or interface to a microcontroller. The FOUT

pin conveys average real power at a pulse frequency many times higher than that of the E1

or E2 pulse fre-

quency, allowing for high speed calibration.

Clock Generator

Crystal Out Crystal In

CPU Clock Output 2

Control Pins

Calibration Pins 5, 23 Program

Selects Frequency Select 7 Current Channel Gain

Select Reset 19

Energy Pulse Outputs

Energy Output 1

High Freq Output Negative Energy

Indicator

1,2,3,4,5,6

, 2

DS547F1 3

1,24

4,6,20,22,21,

18,3

21, 22

XOUT, XIN - A single stage amplifier inside the chip is connected to these pins and can be used with a crystal to provide the system clock for the device. Alternatively, an external clock can be supplied to the XIN pin to provide the system clock for the device.

CPUCLK - Output of on-chip oscillator which can drive one standard CMOS load.

CAL0, CAL1 - Must be tied to a program select pin for calibration. P1, P2, P3, P4, P5, P6, P7 - Used in Calibration, Frequency Select, and Input Gain Select.

FREQ - Must be tied to a program select pin to determine the frequency of E1 and E2. IGAIN - Must be tied to a program select pin to determine the Full-Scale Input Voltage Range of

the current channel.

RESET - Low activates Reset

E1, E2 - The energy output pin issues a fixed-width pulse train output with a rate proportional to

real energy.

FOUT - Outputs energy pulses at a maximum rate of 10 kHz. Used for calibration purposes.

NEG - Low indicates negative energy.

Analog Inputs/Outputs

Differential

9,10

Voltage Inputs Voltage

Reference Output Voltage

Reference Input Differential

16,15

Current Inputs

Power Supply Connections

Positive Digital Supply

Digital Ground 4* Analog Ground 13 Positive

Analog Supply

CS5462

VIN+, VIN- - Differential analog input pins for voltage channel.

VREFOUT - The on-chip voltage reference is output from this pin. The voltage reference has a

nominal magnitude of 2.5 V and is referenced to the AGND pin on the converter. VREFIN - The voltage input to this pin establishes the voltage reference for the on-chip modula-

tor. IIN+, IIN- - Differential analog input pins for current channel.

VD+ - The positive digital supply.

DGND - Digital Ground AGND - Analog Ground VA+ - The positive analog supply.

Notes: 1 Pin number 4 is described as Digital Ground (DGND) and also P1

Pin number 3 is described as Positive Power Supply (VD+) and also P7

Pin number 22 is described as Energy Output 2 (E2) and also P4

Pin number 21 is described as Energy Output 1 (E1) and also P5

Pin number 18 is described as High Frequency Output (FOUT) and also P6

Pin number 6 is described as Negative Energy Indicator (NEG) and also P2

4 DS547F1

CS5462

3. CHARACTERISTICS/SPECIFICATIONS

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

• Typical characteristics and specificat ions are measured at nominal supply voltages and T

= 25 °C.

ANALOG CHARACTERISTICS

Parameter Symbol Min Typ Max Unit

Analog Inputs (Current Channel)

Maximum Differential Input Voltage Range (Gain = 10) {(I

IN+)-(IIN-)} (Gain = 50)

Input Capacitance (All Gain Ranges) CinI -25-pF Effective Input Impedance (All Gain Ranges)(Note 2) Z

Analog Inputs (Voltage Channel)

Maximum Differential Input Voltage Range {(V Input Capacitance CinV -0.2-pF Effective Input Impedance (Note 2) Z

Accuracy (Energy Outputs)

Offset Error VOS - .01 - %F.S. Full-Scale Error (Note 1) FSE - .1 - %F.S.

IN+)-(VIN-)} VIN --500mV

• AGND = DGND = 0 V. All voltages with respect to 0V.

• CAL0 and CAL1 are connected to P4 unless otherwise noted.

IN -

inI 30 - - k

inV 5--M

500 100

mV mV

P-P P-P

P-P

Notes: 1. Applies After System Calibration

2. VA+ = VD+ = 5 V ±10 %; MCLK = 4.096 MHz

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