Turn-on/off driving technique for insulated gate thyristor

Abstract

A turn-on/off driving technique for an insulated gate thyristor which has a first gate electrode insulatively provided above a first base layer and fuctioning as a gate of MOSFET, and a second gate electrode formed on the second base layer. To drive the turn-on of the thyristor, a first voltage for rendering the MOSFET conductive is applied to the first gate electrode, while substantially simultaneously a second voltage for producing forward biasing between the second base layer and a second emitter layer is applied to the second gate electrode. To turn-off drive the thyristor, a third voltage for reverse biasing between the second emitter layer and the second base layer to stop the operation of the thyristor is applied to the second gate, while the MOSFET is kept conductive. The thyristor starts turning off in response to the voltage application. At this time, charge carriers exhausted from the second emitter layer are allowed to flow into the first base layer through the channel region of the MOSFET, thereby suppressing the local concentration of the turn-off current in the thyristor.

Dependencies are inferred from the claim text.