Patent ID: 7605446

Claim:
A bipolar high voltage/power semiconductor device, the device comprising: a drift region of a first conductivity type and having first and second ends; the first end of the drift region having adjacent thereto a region of a second conductivity type which is adjacent a region of the first conductivity type, at least said region of the first conductivity type being in electrical contact with a low voltage terminal such that charge carriers of the first conductivity type are injected into the drift region from said region of the first conductivity type when the device is in the on-state and providing current conduction in a first direction; the second end of the drift region having adjacent thereto a region of the first conductivity type which is adjacent a region of the second conductivity type, at least said region of the second conductivity type being in electrical contact with a high voltage terminal such that charge carriers of the second conductivity type are injected into the drift region from said region of the second conductivity type when the device is in the on-state and providing current conduction in said first direction; a first insulated gate terminal at or towards the first end of the drift region and positioned at least partly over the region of the second conductivity type at the first end of the drift region; a second insulated gate terminal at or towards the second end of the drift region and positioned at least partly over the region of the first conductivity type at the second end of the drift region; and, one or more drive circuits constructed and arranged: (i) to provide a voltage of a first polarity to the second insulated gate terminal relative to the high voltage terminal and to provide a voltage of a second, opposite polarity to the first insulated gate terminal relative to the low voltage terminal, so as to allow current conduction in said first direction; and, (ii) to provide a voltage of the second polarity to the second insulated gate terminal relative to the high voltage terminal and to provide a zero voltage or a voltage of the first polarity to the first insulated gate terminal relative to the low voltage terminal, so as to allow current conduction in a second direction that is opposite the first direction.