| 摘要 |
A current detector includes a chopper circuit composed of a switching circuit, i.e. an inverse-parallel circuit composed of an insulated gate bipolar transistor IGBT and a diode, and a switching circuit, i.e. an inverse-parallel circuit composed of an IGBT and a diode, which are connected in series. When the diode on the opposite arm is turned on, a reverse recovery current is detected and its output is directed to a gate drive circuit via an insulating circuit. A switch in the gate drive circuit is opened to increase resistance, in order to reduce the speed at which the gate of the switching device is charged. Thus, the surge voltage and its increase ratio are reduced without reducing a switching speed or requiring a snubber circuit.
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