Patent ID: 8022710

Claim:
A method for processing a high-voltage DC input signal received from a bus coupled to a module, the method comprising: receiving the high-voltage DC input signal from the bus; generating a common mode AC voltage signal (V CM ) by removing a differential mode voltage component from the high-voltage DC input signal; measuring a magnitude of the common mode AC voltage signal (V CM ); determining whether a measured magnitude of the common mode AC voltage signal (V CM ) is greater than or equal to a fault detection threshold voltage (V TH ); generating an AC fault (ACF) detection signal when the measured magnitude of the common mode AC voltage signal (V CM ) is greater than or equal to the fault detection threshold voltage (V TH ); receiving the ACF detection signal and the common mode AC voltage signal (V CM ); maintaining a count which indicates a number of consecutive periods that the magnitude of the common mode AC voltage signal (V CM ) is greater than or equal to the fault detection threshold voltage (V TH ); and incrementing the count maintained by a register in a cycle counter each time an ACF voltage spike is present in the common mode AC voltage signal (V CM ) while the cycle counter is enabled by the ACF detection signal.