The present invention discloses a power circuit having multiple stages of charge pumps. The power circuit comprises a first charge pump, a second charge pump, a voltage stabilizing capacitor, and an output capacitor. The first charge pump adjusts an input voltage and produces a first output voltage. The second charge pump adjusts the first output voltage, produces a second output voltage, and outputs the second output voltage for driving a loading. The voltage stabilizing capacitor is coupled between the first and second charge pumps and connected externally to the output of the first charge pump. The output capacitor is coupled to the second charge pump for providing the second output voltage. According to the present invention, the effect of supplying large transient currents to the loading can be achieved by connecting externally the voltage stabilizing capacitor to the output of the first charge pump.