Patent ID: 7253637
Filing Date: 2007-08-07
Classification: G01R,H02H

Abstract:
1. A circuit for determining whether arcing is present in an electrical circuit in response to a sensor signal corresponding to current in said electrical circuit, comprising: a filter circuit for analyzing said sensor signal to determine the presence of noise in a predetermined frequency range, and producing a corresponding filtered signal, wherein said filter circuit includes at least two bandpass filters having different passbands; a comparator circuit for comparing the corresponding filtered signal to a reference threshold voltage to generate an output signal, wherein said comparator circuit includes a corresponding at least two comparators, each receiving a reference threshold voltage, and each operable to compare the corresponding filtered signal to a reference threshold voltage to generate an output signal; and a switching circuit for each of the comparators, each switching circuit receiving a plurality of threshold voltages and operating to select one of those threshold voltages as the reference threshold voltage for application to its corresponding comparator circuit.