Drive circuit of power semiconductor device

A drive circuit of a power semiconductor device, comprising:

• a control circuit that controls ON and OFF switching of the power semiconductor device;
• a transistor that turns ON and OFF the power semiconductor device on the basis of a signal from the control circuit;
• a DC power supply that supplies a voltage between control terminals of the power semiconductor device;
• a normally-ON element that is connected between the control terminals of the power semiconductor device not via the transistor that turns ON and OFF the power semiconductor device, a control terminal of the normally-ON device being fixedly connected to ground;
• and
• a diode that is connected in series with the normally-ON element between the control terminals of the power semiconductor device, the diode being directly connected to at least one of the control terminals of the power semiconductor device,
• wherein the DC power supply includes
• a first DC power supply that supplies a positive voltage between the control terminals of the power semiconductor device while the power semiconductor device is in an ON state, and
• a second DC power supply that is connected between a negative terminal of the power semiconductor device and ground and between a positive terminal of the normally-ON element and ground, the second DC power supply supplying a negative voltage to the negative terminal of the power semiconductor device and the negative terminal of the normally-ON element while the power semiconductor device is in an OFF state;
• and
• wherein the normally-ON element turns ON in a case where a power supply voltage of the second DC power supply that supplies the negative voltage to the negative terminal of the power semiconductor device drops below a predetermined value or turns ON in a case where a voltage between the control terminals of the power semiconductor device increases in a state where the power supply voltage of the second DC power supply that supplies the negative voltage to the negative terminal of the power semiconductor device has dropped, and thereby causes a short-circuit between the control terminals of the power semiconductor device.