Patent ID: 7746614
Filing Date: 2010-06-29
Classification: H03K

Abstract:
1. A drive circuit for controlling a switching device ON/OFF, comprising: a short circuit detection means that detects short circuit of the switching device, a soft cutoff means that performs a soft cutoff function by gradually decreasing the gate terminal voltage of the switching device when short circuit is detected by the short circuit detection means, wherein the switching device is one with voltage driven sense function, which is provided with a gate terminal, terminal No. a gate voltage detection means that detects the gate terminal voltage of the switching device, and an ON-pulse retention means that retains the drive circuit output ON when the gate terminal voltage detected by the gate voltage detection means exceeds a first specified value and also the sense current of the switching device exceeds a second specified value so that the soft cutoff function continues to operate when the short circuit is detected while preventing breakdown when a narrow pulse is inputted, wherein the short circuit detection means detects the short circuit of the switching device when the sense current of the switching device exceeds the third specific value.