| 摘要 |
PROBLEM TO BE SOLVED: To provide an overcurrent protection circuit of power semiconductor element which controls, when a fault such as short-circuit is generated, a value of protection resistance for protecting a power semiconductor element, such as IGBT not to become extremely large value and thereby, to prevent the switching time of the power semiconductor element under the short-circuit conditions from becoming very long and also to prevent increase in losses at off condition. SOLUTION: The overcurrent protection circuit is provided at least with a driver control circuit 6, a fault detection circuit 7, a protection circuit, a charge injection circuit 31 and a power supply 9. The charge injection circuit 31 is composed of a one-shot circuit 32, a switch 33 and a resistor 34. The one-shot circuit 32 turns on the switch 33, only for the preset time interval, when a fault detection signal S3 is inputted from the fault detection circuit 7. Thereby, charges are injected from the power supply 9 to an input terminal of the IGBT (TR1), only for the preset time interval. |
