Disclosed is an electronic device and an operation method thereof. The electronic device includes a housing, a battery disposed in the housing, at least one internal device disposed in the housing, a switch connectable to the at least one internal device to supply power received from an external power supply to the at least one internal device. The controller implements the method, including in response to detecting a connection to the external power supply, utilizing power of a first voltage received from the external power supply as operating power of the at least one internal device, and transmitting at least a part of the operating power to the battery to charge the battery, and wherein the received power of the first voltage is supplied to the at least one internal device without step-down.