Patent ID: 7573689

Claim:
An overcurrent detection circuit which detects an overcurrent when the overcurrent flows to an output transistor including an input terminal to which a supply voltage is input, a control terminal to which a control voltage is input, and an output terminal from which an output current is output, the overcurrent detection circuit comprising: a monitor transistor including a control terminal and an output terminal which are connected to the control terminal and the output terminal respectively of the output transistor; an output current detection transistor including an input terminal to which a supply voltage is input, a control terminal to which a detection bias voltage is input, and an output terminal which is connected to an input terminal of the monitor transistor; a constant current source that generates a reference current; a reference transistor including an input terminal to which a supply voltage is input, a control terminal to which the detection bias voltage is input, and an output terminal from which the reference current flows to the constant current source; and a comparison circuit that detects an overcurrent when the overcurrent flows to the output transistor by comparing the voltage of the output terminal of the output current detection transistor and the voltage of the output terminal of the reference transistor, and outputs an overcurrent detection signal.