The ADE7755 is a high accuracy electrical energy measurement
IC. The part specifications surpass the accuracy requirements as
quoted in the IEC1036 standard. See Analog Devices’ Appli-
cation Note AN-559 for a description of an IEC1036 watt-hour
meter reference design based on the AD7755.
The only analog circuitry used in the ADE7755 is in the ADCs
and reference circuit. All other signal processing (e.g., multipli-
cation 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 ADE7755 supplies average real power information on the
low-frequency outputs F1 and F2. These logic outputs may be
used to directly drive an electromechanical counter or interface
to an MCU. The CF logic output gives instantaneous real power
information. This output is intended to be used for calibration
purposes or for interfacing to an MCU.
The ADE7755 includes a power supply monitoring circuit on the
AVDD supply pin. The ADE7755 will remain in a reset condition
until the supply voltage on AVDD reaches 4 V. If the supply falls
below 4 V, the ADE7755 will also be reset and no pulses will be
issued on F1, F2, and CF.
Internal phase matching circuitry ensures that the voltage and
current channels are phase matched whether the HPF in Chan-
nel 1 is on or off. An internal no-load threshold ensures that the
ADE7755 does not exhibit any creep when there is no load.
The ADE7755 is available in a 24-lead SSOP package.