Patent ID: 8917487

Claim:
An overvoltage detection circuit that can detect if an overvoltage condition has occurred at a certain electrical contact point, the overvoltage detection circuit, comprising: an input coupled to the electrical contact point being detected for an overvoltage condition; a circuit that is susceptible to the overvoltage condition coupled to electrical contact point and the overvoltage detection circuit is powered by a supply voltage that is the same as or less than the supply voltage used by the circuit that is susceptible to the overvoltage condition; the supply voltage comprises a positive voltage and negative voltage; a voltage reference circuit coupled to the input, the voltage reference circuit providing a detection point that is set lower than the positive voltage and a second detection point set higher than the negative voltage; and an optoisolator including first and second optoisolator circuits coupled to the voltage reference circuit, the optoisolator generating an overvoltage condition signal if the voltage reference circuit detects an overvoltage condition at the electrical contact point, the overvoltage condition signal being generated by the first optoisolator circuit if an overvoltage condition occurs to the positive voltage and the overvoltage condition signal being generated by the second optoisolator circuit if the overvoltage condition occurs to the negative voltage.