Patent ID: 6380796
Filing Date: 2002-04-30
Classification: H02M,H03K

Abstract:
A semiconductor power converting apparatus comprising:an insulated-gate transistor for controlling a current flowing through a collector and an emitter in response to a gate condition; a driving circuit connected to said gate inputting a drive signal; voltage applying means for applying both a forward bias and a reverse bias to the gate as set the emitter of said insulated-gate transistor to a neutral potential; voltage dividing means for dividing a voltage appearing between the collector of said insulated-gate transistor and the emitter thereof, or a voltage appearing between the collector of said insulated-gate transistor and a minus-sided electrode of said voltage source by employing resistors, in which when said drive signal is an OFF command, a gate voltage of said insulated-gate transistor is brought into such a voltage condition corresponding to the voltage division; and switching means for switching the gate voltage in such a manner that said gate voltage is equal to a negative voltage corresponding to the source voltage of said voltage source when the divided voltage detected by said voltage dividing means is lower than, or equal to a set voltage, and also said gate voltage is equal to a voltage value produced based upon the divided voltage when the divided voltage by said voltage means is higher than, or equal to the set voltage.