The ADE7768 specifications surpass the accuracy require-
ments of the IEC62053-21 standard. The AN-679 Application
Note can be used as a basis for a description of an IEC61036
(equivalent to IEC62053-21) low cost, watt-hour meter
reference design.
The only analog circuitry used in the ADE7768 is in the Σ-Δ
ADCs and reference circuit. All other signal processing, such as
multiplication and filtering, is carried out in the digital domain.
This approach provides superior stability and accuracy over
time and extreme environmental conditions.?
The ADE7768 supplies positive-only average real power
information on the low frequency outputs, F1 and F2. These
outputs can be used to directly drive an electromechanical
counter or interface with an MCU. The high frequency CF logic
output, ideal for calibration purposes, provides instantaneous
positive-only, real power information.
The ADE7768 includes a power supply monitoring circuit on
the VDD supply pin. The ADE7768 remains inactive until the
supply voltage on VDD reaches approximately 4 V. If the supply
falls below 4 V, the ADE7768 also remains inactive and the F1,
F2, and CF outputs are in their nonactive modes.
Internal phase matching circuitry ensures that the voltage and
current channels are phase matched, while the HPF in the
current channel eliminates dc offsets. An internal no-load
threshold ensures that the ADE7768 does not exhibit creep
when no load is present. When REVP is logic high, the
ADE7768 does not generate any pulse on F1, F2, and CF.
The ADE7768 comes in a 16-lead, narrow body SOIC package.