Overcurrent protection circuit

An overcurrent protection circuit comprising:

• a load drive portion that drives a load based on a power supply voltage;
• a wire that connects the load and the load drive portion;
• a current detection portion that detects a load current showing a value of a current flowing through the load, and outputs a sense voltage corresponding to the load current;
• a voltage detection portion that detects the power supply voltage;
• and
• a controller that controls the load drive portion to control a drive of the load, the controller determining an addition-and-subtraction value based on the sense voltage detected by the current detection portion, controlling the load drive portion to cut off the load current when an integration value obtained by adding and subtracting with the addition-and-subtraction value exceeds a determination threshold, and stopping driving the load to protect a protection target from an overcurrent,
• wherein:
• the controller subtracts the integration value based on an elapsed time after cutoff of the load current to obtain a pre-correction integration value when detecting decrease of the power supply voltage and cutting off the load current due to excess of the integration value over the determination threshold;
• the controller, when the power supply voltage increases to a predetermined voltage after the power supply voltage decreases, controls the load drive portion to again start to drive the load, and also calculates a post-correction integration value lower than the pre-correction integration value, by correcting the pre-correction integration value;
• and
• the controller adds and subtracts from the post-correction integration value.