Patent ID: 8913363

Claim:
An overcurrent protection circuit comprising: a switching element configured to adjust electric power by switching control, the electric power being supplied to a load; a current detector configured to detect a switch current flowing through the switching element; and a controller configured to perform the switching control of the switching element based on the switch current detected by the current detector, wherein: the controller includes: a determiner configured to determine whether or not the switch current exceeds a predetermined threshold, that is, the switch current is an overcurrent state when the switching element is turned ON; an OFF period setting counter configured to increase or decrease a counter output depending on a determination result of the determiner; and a drive signal generator configured to generate a drive signal of the switching element such that a length of an ON timing interval of the switching element corresponds to the counter output of the OFF period setting counter, the OFF period setting counter is configured to count up the counter output when the determiner determines that the switch current is the overcurrent state and count down the counter output when the determiner determines that the switch current is not the overcurrent state, and counting down the counter output per determination that the switch current is not the overcurrent state includes two or more steps of counting down from a current value to a base value.