POWER SUPPLY SYSTEM, SLOW-START CIRCUIT, AND CONTROL METHOD

This application discloses a power supply system, including: A first end of a bus capacitor is connected to a first end of a power supply, and a second end of the bus capacitor is connected to a second end of a semiconductor switch device. A first end of the semiconductor switch device is connected to a second end of the power supply. An input end of a power conversion circuit is connected to the bus capacitor. Two ends of a resistor are respectively connected to the first end and the second end of the semiconductor switch device. When the semiconductor switch device is switched off, the power supply supplies power to the bus capacitor by using the resistor. When a voltage of the bus capacitor is greater than a first preset voltage, an auxiliary power supply is powered on and the semiconductor switch device is switched off. When the voltage of the bus capacitor is greater than a second preset voltage, the controller controls the semiconductor switch device to be switched on, where the second preset voltage is greater than the first preset voltage. After the semiconductor switch device is switched on, the power supply supplies power to the bus capacitor by using the semiconductor switch device. The solutions help to select the semiconductor switch device with a smaller volume, reduce a volume of an entire soft-start circuit, and further reduce a volume of the power supply system.