| 摘要 |
A drive circuit for a semiconductor switching element is provided with a semiconductor switching element through which a principal current flows, an overcurrent protection circuit, a short-circuit protection circuit, and a determination time change circuit. The overcurrent protection circuit determines that the principal current has become an overcurrent when sense voltage that is proportional to the magnitude of the principal current exceeds a first threshold value, and decreases the principal current. The short-circuit protection circuit decreases the gate voltage of the semiconductor switching element earlier than the decrease of the principal current by the overcurrent protection circuit when the principal current becomes a larger overcurrent. The determination time change circuit lengthens the determination time required to determine whether the overcurrent protection circuit is operated or not on the basis of the result of a comparison between the result of the determination by the overcurrent protection circuit and a second threshold value as the magnitude of the principal circuit is smaller. |
