Patent ID: 8488287

Claim:
An overcurrent protection circuit applied to a power supply circuit which performs soft-start at the time of activation depending on a terminal voltage of a terminal to which a capacitor is connected, the overcurrent protection circuit is configured to operate in accordance with operation modes comprising: a first operation mode in which when the power supply circuit is activated, the capacitor is charged until the terminal voltage reaches a first voltage; a second operation mode in which depending on a time period in which a current flowing through an output transistor of the power supply circuit exceeds a predetermined value, the capacitor is charged so that the terminal voltage increases from the first voltage toward a second voltage, and the power supply circuit is shut down when the terminal voltage reaches the second voltage; and a third operation mode in which when the power supply circuit is shut down, the capacitor is discharged until the terminal voltage reaches a third voltage, and the shutdown of the power supply circuit is released when the terminal voltage reaches the third voltage.