Patent ID: 8749278

Claim:
A semiconductor device driving unit which supplies, to establish electrical continuity or disconnection in a bus, a drive signal to a gate of a first semiconductor device of a series connection of the first semiconductor device and a second semiconductor device each of which has such a switching function as to be turned on or off according to a voltage of a drive signal applied to the gate, a collector and an emitter of each of which are inserted in the bus, and each of which is connected to a free wheeling diode in parallel, the semiconductor device driving unit comprising: a feedback unit configured to generate a feedback voltage as part of the voltage of the drive signal according to a temporal variation of a current flowing through the bus, wherein the feedback unit comprises: a turn-off feedback unit configured to generate the feedback voltage according to a temporal variation of a collector current of the first semiconductor device in a case that the first semiconductor device is turned off from on; and a turn-on feedback unit configured to generate the feedback voltage according to a commutation current flowing through the free wheeling diode connected to the second semiconductor device in a case that the first semiconductor device is turned on from off, wherein the turn-on feedback unit includes a commutation current direction detecting unit configured to detect a direction of the commutation current, and wherein the turn-on feedback unit is configured to generate the feedback voltage in a case that the commutation current detecting unit detects that the direction of the commutation current corresponds to a reverse recovery interval, and to generate no feedback voltage in other cases.