Patent ID: 8519750

Claim:
A semiconductor switching device drive circuit comprising: a drive power supply configured to apply a drive voltage between a potential reference output terminal of a drive-target switching device and a control terminal of the drive-target switching device; a positive-bias-side series circuit including a positive-bias-side switching device and a positive-bias-side diode having an anode, the anode being a common connection point connected to a positive-bias-side terminal of the drive power supply; a negative-bias-side series circuit including a negative-bias-side switching device and a negative-bias-side diode having a cathode, the cathode being a common connection point connected to a negative-bias-side terminal of the drive power supply; a positive-bias-side capacitor connected in parallel with the positive-bias-side series circuit; a negative-bias-side capacitor connected in parallel with the negative-bias-side series circuit; an inductor connected to the control terminal of the drive-target switching device; and an energization control circuit including first to fourth energization switching devices each connected to the inductor at one end and each having a free wheel diode connected in parallel in a direction opposite to a polarity of the drive power supply, wherein the energization control circuit is configured to control the first to fourth energization switching devices and the positive-bias-side and negative-bias-side switching devices thereby to form: a first path that charges the positive-bias-side capacitor; a second path that connects the drive power supply with the positive-bias-side capacitor in series and energizes the inductor in a direction to charge the control terminal of the drive-target switching device; a third path that charges the control terminal of the drive-target switching device using an electromagnetic energy stored in the inductor; a fourth path that applies a circulating current to the drive power supply when a potential of the control terminal becomes higher than a voltage of the drive power supply; a fifth path that charges the negative-bias-side capacitor; a sixth path that connects the drive power supply with the negative-bias-side capacitor in series and energizes the inductor in a direction to discharge the control terminal of the drive-target switching device; a seventh path that discharges the control terminal of the drive-target switching device using an electromagnetic energy stored in the inductor; and an eighth path that applies a circulating current to the drive power supply when potential of the control terminal becomes lower than potential at a negative-bias-side terminal of the drive power supply.