A power supply circuit is adapted to an electronic device. The power supply circuit includes a drive circuit, a feedback resistor circuit, a battery module and a controller. The drive circuit receives a charger boost indication signal and generates a drive signal accordingly. The feedback resistor circuit has a feedback resistance value changing in response to the drive signal and receives a DC power supply to supply power to a system component. The battery module provides a battery power supply to the system component. The controller controls the battery power supply provided by the battery module according to the feedback resistance value. When the system component is operating in a heavy load state, the controller transmits the corresponding charger boost indication signal to the drive circuit, so as to reduce the feedback resistance value through the drive signal.