Abstract: 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.

Abstract: A powered device (PD) detection device is configured to identify a type of power sourcing equipment. The PD detection device includes a detection circuit and a processing circuit, and the detection circuit is connected to the processing circuit. The detection circuit is configured to: receive hierarchical waveform information sent by the power sourcing equipment, and generate a corresponding first-type signal or a corresponding second-type signal based on the hierarchical waveform information, and is further configured to send the first-type signal or the second-type signal to the processing circuit, where the first-type signal corresponds to first-type power sourcing equipment, and the first-type power sourcing equipment includes at least one of non-standard power sourcing equipment and a direct current adapter.

Abstract: The power supply system includes a first voltage conversion unit, where the first voltage conversion unit is an isolated voltage conversion unit, and the first voltage conversion unit is connected to a power supply, and is configured to convert a voltage of the power supply into a power supply voltage of the service board, that is, a first voltage; and a second voltage conversion unit, where the second voltage conversion unit is a non-isolated voltage conversion unit, the second voltage conversion unit is deployed on the service board, and the second voltage conversion unit is configured to convert the first voltage into a power supply voltage of a first load module on the service board, that is, a second voltage.

Abstract: A powered device PD detection device is configured to identify a type of power sourcing equipment. The PD detection device includes a detection circuit and a processing circuit, and the detection circuit is connected to the processing circuit. The detection circuit is configured to: receive hierarchical waveform information sent by the power sourcing equipment, and generate a corresponding first-type signal or a corresponding second-type signal based on the hierarchical waveform information, and is further configured to send the first-type signal or the second-type signal to the processing circuit, where the first-type signal corresponds to first-type power sourcing equipment, and the first-type power sourcing equipment includes at least one of non-standard power sourcing equipment and a direct current adapter.