POWER SOURCE SELECTION CIRCUIT AND ELECTRONIC DEVICE USING THE SAME

摘要

A power source selection circuit includes an external power port and a battery compartment, which are used to connect to an external power source and a battery module, respectively. The power source selection circuit further includes a selection switch including a control terminal connected to the external power port, and a first path terminal connected to the battery compartment. A first unidirectional switch connects a second path terminal of the selection switch to a power output port. A second unidirectional switch connects the external power port to the output terminal. When the external power port is connected to the external power source, the control terminal of the selection switch is at a high voltage and the selection switch is cut off accordingly, thereby the path from the battery module to the power output port is cut off and the external power source provides power to the output port.