ADE7761

The ADE7761 is an accurate fault tolerant electrical energy measurement IC intended for use in two-wire distribution systems. It is a pin reduction version of ADE7751 with an enhancement of the missing neutral detection and a precise oscillator circuit that serves as a clock source to the chip. The ADE7761 eliminates the cost of external circuitry for missing neutral detection and billing as well as an external crystal or resonator, thus reducing the overall cost of a meter built with this IC.The ADE7761 provides instantaneous and average real power based on line voltage and current. The part specifications surpass the accuracy requirements as quoted in the IEC61036 standard. The only analog circuitry used on the ADE7761 is in the ADCs and reference circuit. All other signal processing (e.g., multiplication 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 and a missing neutral detection schemes, which both warns of fault conditions or missing neutral conditions and allows the ADE7761 to continue accurate billing during a fault or missing neutral events. The Fault condition is detected by continuously monitoring both the phase and neutral (return) currents. A fault is indicated when these currents differ by more than 6.25%, and billing is continued using the larger of the two currents. The missing neutral condition is detected by continuously monitoring the voltage and current inputs. A Missing Neutral condition is indicated when no voltage input is detected, and billing is continued using the current signal. Gain calibration between channels and for Missing Neutral mode are adjusted external to this device. The ADE7761, available in 20-lead SSOP package, is pin compatible with the ADE7760.ADE7760 offers similar features as ADE7761 without missing neutral detection.