USB power circuit, power socket equipped with USB power circuit and electric appliance equipped with USB power circuit

The utility model relates to a USB power circuit, a power socket and an electric appliance. The USB power circuit comprises a power conversion circuit, a starting switch, a power supply switch circuit, a detection circuit and an MCU control circuit. An output end of the power conversion circuit is connected with a USB interface; the starting switch is used for connecting mains power input to the power conversion circuit when a USB power supply is started to supply power; the power supply switch circuit is used for connecting the mains power input to the power conversion circuit during the power supplying period of the USB power supply; the detection circuit is used for detecting output current of the power conversion circuit; and the MCU control circuit is connected to the detection circuit and the power supply switch circuit and is used for controlling the power supply switch circuit to disconnect the mains power input and the power conversion circuit in a predetermined period of time when the output current is smaller than a predetermined value. By implementing the USB power circuit, mobile electronic equipment can be charged or power can be supplied to the mobile electronic equipment, the mains power input of the USB power circuit can be cut automatically after charging or power supply is completed, zero power consumption is achieved, and the purposes of energy saving and emission reduction are achieved. Meanwhile, the hidden danger that a fire may be caused when an ordinary USB power converter is not timely pulled out after being used can be eliminated.