Patent ID: 8531857

Claim:
A method for driving a power supply device including a plurality of reverse conducting semiconductor devices used in combination, wherein: each reverse conducting semiconductor device includes an IGBT (insulated gate bipolar transistor) domain and a diode element domain coexisting in a semiconductor substrate, in the IGBT domain, an emitter region, a body region, a drift region and a collector region are layer-stacked, and a trench gate electrode penetrating the body region that separates the emitter region from the drift region is formed, and in the diode element domain, a body contact region, a body region, a drift region and a drift contact region are layer-stacked and a trench gate electrode extending from a surface of the semiconductor substrate to the drift region is formed, the driving method comprising: applying a first polarity voltage at least to the trench gate electrode of the IGBT domain of one reverse conducting semiconductor device in a case where an electric power is to be supplied by switching the IGBT domain of the one reverse conducting semiconductor device to an on-state; and applying a second polarity voltage at least to the trench gate electrode of the diode element domain of another reverse conducting semiconductor device in a case where return current flows in the diode element domain of the other reverse conducting semiconductor device by switching the IGBT domain of the one reverse conducting semiconductor device to an off-state.