Electronic device and charging method thereof

A charging method, comprising:

• coupling an adapter to an electronic device through a bus interface;
• identifying whether the adapter supports direct charging;
• and
• controlling the electronic device to operate in a general charging mode or a direct charging mode;
• receiving a bus voltage through the bus interface and an overvoltage protection unit by a charging unit in the electronic device and converting the bus voltage into a charging voltage to charge an energy storage unit in the electronic device when the electronic device operates in the general charging mode, wherein a first terminal of the overvoltage protection unit is electrically coupled to the adapter, and a second terminal of the overvoltage protection unit is electrically coupled to the charging unit and a switch unit, wherein the overvoltage protection unit receives the bus voltage from the adapter and protects the charging unit and the switch unit from an overvoltage/overcurrent of the bus voltage, wherein the switch unit comprises a first terminal, a second terminal, a first switch, a second switch, and two resistors, wherein the first switch comprises a control end, wherein the second switch comprises a control end, wherein each of the two resistor comprises a terminal, wherein the first switch is directly adjacent to the second switch, wherein the control end of the first switch, the control end of the second switch, and the terminals of each of the two resistor are electrically coupled to the first terminal of the switch unit;
• outputting an on/off switching signal to turn on the switch unit by a charge switching circuit to form a direct charging path, and charging the energy storage unit by the bus voltage when the electronic device operates in the direct charging mode;
• and
• outputting a corresponding on/off switching signal to turn off the switch unit by the charge switching circuit to disconnect the direct charging path via the first switch, the second switch, and the two resistors of the switch unit when the electronic device is disconnected from the adapter.