Until a vehicle system is activated, a switching circuit outputs a pilot signal to an OR circuit. As a result, lowering of the potential of the pilot signal caused by a resistance circuit is avoided, and the pilot signal is provided in a non-pulsed manner. A power supply CPU is activated in accordance with any one of a connector signal and the non-pulsed pilot signal. When the vehicle system is activated, the switching circuit switches an output destination of the pilot signal to the resistance circuit.