The present invention discloses a power management circuit, including: a first voltage regulator, which converts an input voltage to an output voltage; a second voltage regulator coupled between the output voltage and a battery; and a voltage difference control circuit, which receives the output voltage and a voltage of the battery, and outputs a voltage difference control signal to control the first voltage regulator. The voltage difference control circuit includes: a battery reference voltage determination circuit, which generates a battery reference voltage related to the battery voltage, and an error amplifier, which receives the output voltage and the battery reference voltage and generates the voltage difference control signal.