Patent ID: 8994437
Filing Date: 2015-03-31
Classification: H02M,H03K

Abstract:
1. A circuit for controlling a potential of a gate of an insulated gate type switching device, the circuit comprising: a semiconductor device comprising a first signal output terminal, and configured to output a signal to control a potential of a gate of an insulated gate type switching device; an inverting circuit connected to the first signal output terminal, and configured to invert the signal output to the first signal output terminal and to output the inverted signal; a first insulated gate type switching device including a gate that is connected the inverting circuit and receives the inverted signal output from the inverting circuit; a second insulated gate type switching device connected to the first insulated gate type switching device in series; and a low potential wiring being at a potential lower than an average potential of the signal output from the inverting circuit; wherein the semiconductor device is capable of receiving a reference signal or internally creating the reference signal, the semiconductor device is capable of switching between a first operation and a second operation, the first operation outputs to the first signal output terminal a signal that is at a third potential when the reference signal is at a first potential, and that is at a fourth potential higher than the third potential when the reference signal is at a second potential, and the second operation outputs to the first signal output terminal a signal that is at the fourth potential when the reference signal is at the first potential, and that is at the third potential when the reference signal is at the second potential, the semiconductor device is set to work under only one of the first operation or the second operation, the semiconductor device comprises a first signal creating circuit configured to create the signal to be output to the first signal output terminal, the first signal creating circuit comprises a first switching device, the inverting circuit comprises a second switching device, an ampacity of the second switching device is larger than an ampacity of the first switching device, the circuit further comprises a third switching device connected between a gate of the first insulated gate type switching device and the low potential wiring, the semiconductor device further comprises a second signal output terminal and the second signal creating circuit, the second signal output terminal is connected to the third switching device, and the second signal creating circuit is configured to create a signal to be output to the second signal output terminal, the third switching device is configured to switch according to the signal output to the second signal output terminal, the second signal creating circuit comprises a fourth switching device and configured to create the signal so that the third switching device is turned on at least at a moment when the second insulated gate type switching device switches from off to on, and an ampacity of the third switching device is larger than an ampacity of the fourth switching device.