Patent ID: 7295412
Filing Date: 2007-11-13
Classification: B60K,B60L,B60W,H02H,H02M,H03K,Y02T

Abstract:
1. A protection circuit for a power semiconductor device having a collector, a gate, and an emitter, the circuit comprising: a first comparator which detects a collector voltage of said power semiconductor device to output a first detection signal when the detected collector voltage exceeds a first reference voltage; a second comparator which detects a gate voltage of said power semiconductor device to output a second detection signal, when the detected gate signal exceeds a second reference voltage which is set, relative to the potential at the emitter of said power semiconductor device, to be lower than a line power voltage of a drive circuit for outputting a drive signal that drives said power semiconductor device and higher than a terraced voltage of the power semiconductor device; logic means for outputting a protection start signal when both the first and second detection signals are being output; and gate voltage reduction means for reducing said gate voltage in accordance with the protection start signal from said logic means, said power semiconductor device being a trench type power semiconductor device.