A fast charging circuit includes a switching charger and a first bypass charging circuit. The input end of the switching charger receives an input voltage, and the output end of the switching charger is coupled to a battery through a first switch and is coupled to a system terminal. The first bypass charging circuit includes a second switch between its input end and output end. The input end of the first bypass charging circuit receives the input voltage, and the output end of the first bypass charging circuit is coupled to the system terminal through the first switch and is coupled to the battery. When the voltage of the battery is low, the first switch is turned on and the second switch is turned off, but when the voltage of the battery is high, the second switch and the third switch are turned on.