ANALOG DEVICES ADE78xx Service Manual

ADE7878, ADE7868, ADE7858, ADE7854

Polyphase Multifunction Energy Metering ICs

Features

•Supplies total (fundamental

and harmonic) active/reactive/
apparent energy and fundamental
active/reactive energy on each
phase and on the overall system

•Highly accurate; supports

EN 50470-1, EN 50470-3,
IEC 62053-21, IEC 62053-22,
and IEC 62053-23

•Compatible with 3-phase, 3- or

4-wire (delta or wye), and other
3-phase services

•Less than 0.1% error in active and

reactive energy over a dynamic
range of 1000 to 1 at 25°C

•Less than 0.2% error in active and

reactive energy over a dynamic
range of 3000 to 1 at 25°C

•Supports current transformer

and di/dt current sensors

•Dedicated ADC channel for the

neutral current input

•Supplies sampled waveform

data on all 3 phases and neutral
current

•Single 3.3 V supply

•40-lead, lead-free, lead frame

chip scale package (LFCSP)

•Operating temperature

–40° to +85°C

2

•Flexible I

interfaces

C®, SPI, HSDC serial

Overview

The ADE7878, ADE7868, ADE7858, and ADE7854 are high accuracy,
3-phase electrical energy measurement ICs with serial interfaces and three
flexible pulse outputs. They incorporate six or seven second-order Σ-∆
ADCs, a digital integrator, reference circuitry, and all the signal processing
required to perform total (fundamental and harmonic) active, reactive,
and apparent energy measurement, fundamental only active and reactive
energy measurement, and rms calculations.

These metering ICs are suitable to measure active, reactive, and apparent
energy in various 3-phase configurations, such as wye or delta services,
with both three and four wires. They provide system calibration features for
each phase: rms offset correction, phase calibration, and gain calibration.

The CF1, CF2, and CF3 logic outputs provide a wide choice of power
information: total/fundamental active/reactive power, total apparent power,
or sum of current rms values.

www.analog.com/energymeter

Functional Block Diagram

27

CLKIN

28

CLKOUT

13

ICP

14

ICN

19

VCP

18

VN9IBP

PGA3

PGA3

PGA1

PGA1

12

IBN

22

VBP

ADC

ADC

ADC

ADC

ADC

PGA3

PGA1

PGA2

ADC

ADC

16

INN15INP

7

IAP

8

IAN

23

VAP

17

REF

IN/OUT

26

VDD

25

AGND

24

AVDD5DVDD

6

DGND

4

RESET

1.2V

REF

POR

LDO

LDO

APHCAL

AVGAIN

HPF

AIGAIN

HPF

DIGITAL

INTEGRATOR

NIGAIN

HPF

DIGITAL

INTEGRATOR

TOTAL/FUNDAMENTAL ACTIVE/REACTIVE

ENERGIES, APPARENT ENERGY AND VOLTAGE/

CURRENT RMS CALCULATION FOR PHASE B

(SEE PHASE A FOR DETAILED DATA PATH)

TOTAL/FUNDAMENTAL ACTIVE/REACTIVE

ENERGIES, APPARENT ENERGY AND VOLTAGE/

CURRENT RMS CALCULATION FOR PHASE C

(SEE PHASE A FOR DETAILED DATA PATH)

HPFDIS [23:0]

HPFDIS [23:0]

HPFDIS [23:0]

X

2

NIRMS

LPF

NIRMSOS

COMPUTATIONAL

BLOCK FOR TOTAL

REACTIVE POWER

X

2

AIRMS

LPF

AIRMSOS

X

2

AVRMS

LPF

LPF

AVRMSOS

AVAGAIN

AWGAIN

AWATTOS

AVARGAIN

AVAROS

PHASE

A, B,

AND

C DATA

AFWGAIN

AFWATTOS

AFVARGAIN

AFVAROS

DFC

CFxDEN

:

33

CF1

DFC

CFxDEN

:

34

CF2

DFC

CFxDEN

:

35

CF3/HSCLK

COMPUTATIONAL

BLOCK FOR

FUNDAMENTAL

ACTIVE AND

REACTIVE POWER

36

32

29

SPI/I2C

I2C

IRQ0

IRQ1

SCLK/SCL

38

MOSI/SDA

37

MISO/HSD

39

SS/HSA

HSDC

DIGITAL SIGNAL

PROCESSOR





General Description

The ADE7878, ADE7868, ADE7858, and ADE7854 have waveform sample registers that allow access to all
ADC outputs. These devices also incorporate power quality measurements such as short duration low or high
voltage detections, short duration high current variations, line voltage period measurement, and angles between
phase voltages and currents. Two serial interfaces can be used for communication: SPI or I
speed interface, HSDC (high speed data capture) port, can be used in conjunction with I
the ADC outputs and real-time power information. Two interrupt request pins, IRQ0
enabled interrupt event has occurred.

The table below indicates feature sets available for each of the products. All products provide the same level
of performance and accuracy. The ADE7854 features active energy measurements only. The ADE7858 adds
reactive energy measurements. The ADE7868 and ADE7878 include a seventh ADC channel for neutral current
measurements. These parts also include advanced antitamper features and power-down modes. The ADE7878
adds fundamental active and reactive power measurements.

Part Number Watt VAR

Tamper

Detect

Low Power

Modes

ADE7878 • • • • •

ADE7868 • • • •

ADE7858 • •

ADE7854 •

2

C. A dedicated high

2

C to provide access to

and IRQ1, indicate that an

Fundamental

Powers

ADE7878

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