Patent ID: 9257830
Filing Date: 2016-02-09
CPC Classification: H01H,H02H,H03K

Claim Text:
1. A semiconductor device comprising: a semiconductor switching element; an overvoltage protection circuit to protect the switching element from overvoltage; a resistance circuit to transmit a control signal for turning the switching element ON and OFF to a control terminal of the switching element; a first switching means for receiving, through the overvoltage protection circuit, a signal corresponding to a voltage appearing at an output terminal of the switching element on turning OFF of the switching element; a second switching means for operating according to a voltage of a first capacitor connected to an output side of the first switching means to increase a resistance value of the resistance circuit; and a timing control means for controlling timing of operating the second switching means in accordance with the voltage of the first capacitor, the first capacitor being charged or discharged responsive to a level of the control signal, wherein the timing control means turns off the second switching means by discharging the first capacitor with the control signal before the elapse of an ON time of the control signal causes an excessive current to flow in the switching element, and slows a turn-off speed of the switching element by increasing the resistance value.