Power supply switching circuit and method based on power supply insertion detection

The invention discloses a power supply switching circuit and method based on power supply insertion detection, belongs to the technical field of power supply switching, and aims to solve the technical problem of how to realize stable power supply switching. Comprising a single-chip microcomputer, a power supply insertion detection circuit and a power supply switching circuit. The power supply insertion detection circuit is a triode switching circuit, and the single chip microcomputer is used for detecting whether an external power supply is inserted or not through the power supply insertion detection circuit; the power supply switching circuit is composed of an MOS tube, a resistor and a capacitor, the single-chip microcomputer is used for carrying out power supply switching through the power supply switching circuit, and the power supply switching process comprises the steps that a power supply of external equipment is switched firstly, and then the power supply of the single-chip microcomputer is switched.