An electronic device and method and power supply are disclosed. The electronic device includes comprising a connector for electrically coupling with an external power supply unit, and a processor. The processor implements the method, which includes detecting a connection state with the external power supply unit, and detecting whether power supplied from the external power supply unit is abnormal, and controlling the power when the power supplied has an abnormal value. The power supply may include a connector for electrically coupling with an electronic device, and a processor for detecting a connection state with the electronic device, detecting whether power supplied to the electronic device by the power supply unit has an abnormal value, and controlling the supplied power when the power is abnormal.