The present invention relates to a power circuit of displaying device, which comprises a timing controller, a control circuit, and a charge pump (single or multiple stages). The timing controller outputs a timing control signal to the control circuit. The control circuit outputs a clock signal or a capacitance adjusting signal according to the timing control signal. The charge pump receives the input voltage and outputs an output voltage according to the clock signal or the capacitance adjusting signal. The output voltage is provided to the scan driver for generating a plurality of scan driving signals. Accordingly, by increasing the rise rate of the output voltage of the charge pump in the voltage conversion time and reducing the rise rate of the output voltage close to the voltage holding time, the present invention can achieve the effect of reducing the power consumption.