ADE7878:  Polyphase Multifunction Energy Metering IC with per Phase Active and Reactive Powers

The ADE7878 is a high accuracy, 3-phase electrical energy measurement IC with serial interfaces and three flexible pulse outputs. The ADE7878 incorporates second-order sigma-delta (Σ-Δ) analog-to-digital converters (ADCs), a digital integrator, reference circuitry, and all the signal processing required to perform total (fundamental and harmonic) active, reactive, and apparent energy measurement and rms calculations, as well as fundamental only active and reactive energy measurement and rms calculations. A fixed function digital signal processor (DSP) executes this signal processing. The DSP program is stored into internal ROM memory.

The ADE7878 is suitable for measuring active, reactive, and apparent energy in various 3-phase configurations, such as wye or delta services, with both three and four wires. The ADE7878 provides system calibration features for each phase, that is, rms offset correction, phase calibration, and gain calibration. The CF1, CF2, and CF3 logic outputs provide a wide choice of power information: total active, reactive, and apparent powers, or the sum of the current rms values, and fundamental active and reactive powers.

The ADE7878 contains waveform sample registers that allow access to all ADC outputs. The device also incorporates 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, SPI and I2C, can be used to communicate with the ADE7878. A dedicated high speed interface, the high speed data capture (HSDC) port, can be used in conjunction with I²C to provide access to the ADC outputs and real-time power information. The ADE7878 also has two interrupt request pins, IRQ0 and IRQ1, to indicate that an enabled interrupt event has occurred. For the ADE7878, three specially designed low power modes ensure the continuity of energy accumulation when the ADE7878 is in a tampering situation.

The ADE7878 is available in a 40-lead LFCSP, Pb-free package.

Applications

• Energy metering systems