Patent ID: 8531170

Claim:
A semiconductor device comprising: an output transistor including a control terminal connected to a drive signal input terminal, a first terminal connected to a power supply terminal, and a second terminal connected to an output terminal, the output terminal being to be connected to a load; a detection transistor including a control terminal commonly connected to the control terminal of the output transistor, and a first terminal connected to the power supply terminal, the detection transistor monitoring a current flowing through the output transistor and generating a detection current that is proportional to an output current; a detection voltage generation unit that is connected between a second terminal of the detection transistor and the output terminal, the detection voltage generation unit generating a detection voltage based on the detection current; a protection transistor including a first terminal connected to the control terminal of the output transistor, and a second terminal connected to the output terminal, the protection transistor drawing a current from the control terminal of the output transistor to the output terminal when the detection voltage reaches a threshold voltage that is set in advance; and a limited current generation circuit that generates a limit setting current that sets an output current flowing through the output transistor in a state in which a current flows through the protection transistor, generates a limited current that is obtained by converting the limit setting current according to a variation of the threshold voltage of the protection transistor and a variation of the detection voltage with respect to the detection current, and supplies the limited current to the first terminal of the protection transistor.