ADE7761_15 Datasheet, PDF (1/28 Pages) Analog Devices – Energy Metering IC with On-Chip Fault and Missing Neutral Detection

Energy Metering IC with On-Chip
Fault and Missing Neutral Detection
ADE7761
FEATURES
GENERAL DESCRIPTION
High accuracy active energy measurement IC, supports
IEC 687/61036
Less than 0.1% error over a dynamic range of 500 to 1
Supplies active power on the frequency outputs F1 and F2
High frequency output CF is intended for calibration and
The ADE7761 is a high accuracy, fault tolerant, electrical energy
measurement IC intended for use with 2-wire distribution
systems. The part specifications surpass the accuracy require-
ments as quoted in the IEC61036 standard.
supplies instantaneous active power
Continuous monitoring of the phase and neutral current
allows fault detection in 2-wire distribution systems
Current channels input level best suited for current
transformer sensors
Uses the larger of the two currents (phase or neutral) to
E _{bill—even during a fault condition}
Continuous monitoring of the voltage and current inputs
allows missing neutral detection
T Uses one current input (phase or neutral) to bill when
missing neutral is detected
Two logic outputs (FAULT and REVP) can be used to indicate
a potential miswiring, fault, or missing neutral condition
E Direct drive for electromechanical counters and 2-phase
stepper motors (F1 and F2)
Proprietary ADCs and DSP provide high accuracy over large
variations in environmental conditions and time
L Reference 2.5 V ± 8% (drift 30 ppm/°C typical) with external
overdrive capability
Single 5 V supply, low power
The only analog circuitry used on the ADE7761 is in the ADCs
and reference circuit. All other signal processing (such as multi-
plication and filtering) is carried out in the digital domain. This
approach provides superior stability and accuracy over extremes
in environmental conditions and over time.
The ADE7761 incorporates a fault detection scheme similar to
the ADE7751 by continuously monitoring both the phase and
neutral currents. A fault is indicated when these currents differ
by more than 6.25%.
(continued on Page 3)
SO _{V1A 2}
V_1N 4
B _{V1B 3}
MISCAL 7
O^{V2P 6}
FUNCTIONAL BLOCK DIAGRAM
AGND
8
FAULT
15
ADC
ADC
ADC
ADC
A>B
HPF
B>A
A<>B
ZERO CROSSING
DETECTION
MISSING NEUTRAL
GAIN ADJUST
V_DD
1
POWER
SUPPLY MONITOR
ADE7761
SIGNAL PROCESSING
BLOCK
LPF
V_2N 5
MISSING NEUTRAL
DETECTION
2.5V
4kΩ
REFERENCE
INTERNAL
OSCILLATOR
DIGITAL-TO-FREQUENCY CONVERTER
9
REF_IN/OUT
14
RCLKIN
17
DGND
Figure 1.
10 11 12 16 18 19 20
SCF S1 S0 REVP CF F2 F1
Rev. A
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