| 摘要 |
PURPOSE:To provide the switching element drive circuit reducing a turn-on/turn- off time automatically and preventing a damage to a voltage drive switching element due to a surge voltage. CONSTITUTION:A switching element drive circuit which is driven by applying a voltage to a voltage drive switching element 1 provided with a load 2 between a collector and an emitter to drive the switching element 1 is provided with a variable gate resistor circuit 4 connected in series with a gate of the element 1, a current transformer CT detecting a load current Io fed to the load 2, a voltage detector 5 detecting a collector-emitter voltage of the element 1. The resistance of the variable gate resistor circuit 4 is controlled variably based on a change of the load current Io and whether or not a voltage is a surge voltage. Through the constitution above, the turn-on/turn-off time of the element is reduced automatically and the defect of the element 1 due to a surge voltage is prevented. |
