An electronic device includes a first rechargeable battery, a solar cell mounted on the electronic device, a second rechargeable battery and a power management circuit. The power management circuit includes a control module, a DC/DC module, a switch and a power supply switching module. The DC/DC module is configured for converting the DC power generated by the solar cell from one voltage level to another, and activating and maintaining the activation of the control module. The switch is turned on by the control module when the control module is activated, causing the DC power from the DC/DC module to charge the second rechargeable battery. The power supply switching module is controlled by the control module to select the second rechargeable battery to power the electronic device if the voltage level of the rechargeable battery is lower than that of the second rechargeable battery.