A power supply system includes an MPU, multiple power conversion circuits, and multiple extended-control circuits. The MPU supplies a digital switching driving signal to the power conversion circuit, and supplies a digital switching driving signal to the power conversion circuit. The extended-control circuit, which includes a CR circuit, generates a switching driving signal which is delayed with respect to the digital switching driving signal, and supplies the switching driving signal to the power conversion circuit. The extended-control circuit, which includes a CR circuit, generates a switching driving signal which is delayed with respect to the digital switching driving signal, and supplies the switching driving signal to the power conversion circuit.