Patent ID: 6072356
Filing Date: 2000-06-06
Classification: G01R

Abstract:
A circuit for deriving a signal representative of an AC power line voltage signal, comprising:first and second AC power line wires for conveying said AC line voltage signal;first and second sense wires non-conductively mounted adjacent to said first and second AC power line wires respectively for receiving said signal representative of said AC line voltage signal, said first and second sense wires receiving said representative signal from said AC power line wires via capacitive coupling; anda signal processing channel coupled to said sense wires for receiving said representative signal and producing an amplified and filtered representative signal of said representative signal at an output;said processing channel includinga differential amplifier having a pair of input terminals coupled to respective ones of said first and second sense wires, and having a single-ended output;a lowpass filter, having an input coupled to said output of said differential amplifier, for reducing undesired high frequency components of said representative signal; anda further amplifier circuit for producing an amplified representative signal, said further amplifier including an amplitude limiting circuit for limiting amplitude excursions of said amplified representative signal.