Electronic device and power supplying control method thereof

A electronic device and a power supplying method thereof are provided. The device includes a system unit, an internal power supplying unit and a power controller. The internal power supplying unit is coupled to the system unit, and supplies a system voltage to the system unit. The power controller is coupled to the system unit and the internal power supplying unit, and determines a source of the external voltage according to a voltage value of the external voltage. When the power controller determines that the source of the external voltage is a mobile power supply device, the power controller provides the external voltage to the system unit, and does not charge the internal power supplying unit with the external voltage. The voltage value of the external voltage provided by the mobile power supply device is higher than the voltage value of the system voltage.