Patent ID: 8093660

Claim:
A semiconductor device comprising: a first bipolar transistor having a first conduction node connected to a first electrode node, a second conduction node connected to a second electrode node and a first base node; a first insulated gate field effect transistor of a first conductivity type connected between the second electrode node and the base node of the first bipolar transistor, and selectively placed in a conductive state according to a control signal and connecting electrically the second electrode node to the base node of the first bipolar transistor when made conductive; a second insulated gate field effect transistor of a second conductivity type having a gate electrode, a third conduction node electrically connected to the first electrode node and a fourth conduction node electrically connected to the base node of the first bipolar transistor, and the second insulated gate field effect transistor selectively placed in a conductive state according to a voltage on the gate electrode and a voltage on the first electrode node and connecting electrically the first electrode node to the base node of the first bipolar transistor when made conductive; and a voltage mitigating element connected between the second electrode node and the gate electrode of the second insulated gate field effect transistor, for mitigating a voltage applied across a gate insulating film of the second insulated gate field effect transistor when the first bipolar transistor is off, wherein a voltage at the first conduction node is greater than a voltage at the second conduction node.