Gate control circuit for voltage drive switching element

Abstract

A gate control circuit for turning on and off an insulated gate semiconductor device having gate, emitter and collector terminals, including a first DC power source coupled to the gate terminal via a first switch and configured to apply a positive voltage to the gate terminal in order to turn on the insulated gate semiconductor device when the first switch is turned on and the second switch is turned off; a second DC power source coupled to the gate terminal via a second switch and configured to apply a negative voltage to the gate terminal in order to turn off the insulated gate semiconductor device when the second switch is turned on and the first switch is turned off; a parallel circuit of a diode and a capacitor coupled in series to the second switch; and a turn off assist circuit configured to produce a negative charge on the capacitor to assist in turning off the insulated gate semiconductor device. In a power converter circuit having a plurality of insulated gate semiconductor devices, equalization of delay times for turning off the insulated gate semiconductor devices is achieved by controlling a charged stored in the capacitor of each gate control circuit based on detected collector-emitter voltages or detected emitter currents.