ADE7762ARWZ Analog Devices Inc, ADE7762ARWZ Datasheet - Page 22

• Manufacturer Part Number: ADE7762ARWZ
• Description: IC, POLYPHASE ENERGY METERING, SOIC-28
• Manufacturer: Analog Devices Inc

Specifications of ADE7762ARWZ

• Ic Function: Polyphase Energy Metering IC With Phase Drop Indication
• Supply Voltage Range: 4.75V To 5.25V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: SOIC
• No. Of Pins: 28
• Input Impedance: 140 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.8V
• Current - Supply: 8.5mA
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (0.300", 7.50mm Width)
• Meter Type: 3 Phase
• Brief Features: On-Chip Creep Protection, High Frequency Output
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: EVAL-ADE7762EBZ - BOARD EVALUATION FOR ADE7762
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

ADE7762
ACCUMULATION OF 3-PHASE POWER
Power Measurement Considerations
Calculating and displaying power information always have
some associated ripple that depends on the integration period
used in the MCU to determine average power as well as the
load. For example, at light loads, the output frequency can be
10 Hz. With an integration period of 2 seconds, only about
20 pulses are counted. The possibility of missing one pulse
always exists because the ADE7762 output frequency is running
asynchronously to the MCU timer. This results in a 1-in-20
or 5% error in the power measurement. To remedy this, an
appropriate integration time should be considered to achieve
the desired accuracy.
Mode Selection of the Sum of the Three Active Energies
The ADE7762 can be configured to execute the arithmetic sum
of the three active energies, Wh = Wh
sum of the absolute value of these energies, Wh = |Wh
|Wh
made by setting the ABS pin. Logic high and logic low applied
on the ABS pin correspond to the arithmetic sum and the sum
of absolute values, respectively.
When the sum of the absolute values is selected, the active
energy from each phase is always counted positive in the total
active energy. It is particularly useful in 3-phase, 4-wire installa-
tion where the sign of the active power should always be the
ΦB
| + |Wh
ΦC
|. The selection between the two modes can be
ΦA
+ Wh
ΦB
+ Wh
ΦA
ΦC
| +
, or the
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same. If the meter is misconnected to the power lines, that is,
if CT is connected in the wrong direction, then the total active
energy recorded without this solution can be reduced by
two-thirds.
The sum of the absolute values assures that the active energy
recorded represents the actual active energy delivered. In this
mode, the reverse power pin still detects when the arithmetic
sum of the active powers is negative, but energy continues to
accumulate regardless of the sign.
Negative Total Power Detection
The ADE7762 detects when total power, calculated as the
arithmetic sum of the three phases, is negative. This detection
is independent of the mode of the sum of the three powers
(arithmetic or absolute). This mechanism can detect an incor-
rect connection of the meter or generation of negative active
energy. When the sum of the powers of the three phases is
negative, the REVP pin output goes active high. When the
sum of the powers of the three phases is positive, the REVP
pin output is reset to low.
The REVP pin output changes state at the same time that a
pulse is issued on CF. If the sum of the powers of the three
phases is negative, then the REVP pin output stays high until
the sum of the three phases’ power is positive or until all three
phases are below the no-load threshold.