Patent ID: 8901918

Claim:
A circuit for detecting a load connection state of a load connected between an output terminal and a ground, the load allowing a direct current to flow therethrough, comprising: a first switch element having a first end connected to a power source, a second end; and a control end; a second switch element having a first end connected to the power source or the ground, a second end connected to the control end of the first switch element, and a control end connected to the second end of the first switch element through a first resistor; a diode provided between the second end of the first switch element and the output terminal, a potential difference between both ends of the diode changing due to a temperature change, a second resistor connected between the control end of the second switch element and the ground; and a third resistor connected between the power source and the first end of the first switch element, wherein the diode performs temperature compensation for a voltage value in the control end of the second switch element while preventing a current from flowing from the output terminal into the first and second switch elements when an external voltage is applied to the output terminal, and wherein an electric potential applied to the control end of the second switch element is a combined potential including respective electric potentials due to the first and second resistors, a voltage difference between both ends of the third resistor, and an electric potential of the diode.