Patent ID: 7876585
Filing Date: 2011-01-25
Classification: H02M

Abstract:
1. A voltage providing circuit, for generating an output voltage, comprising: an oscillating circuit, for providing a clock signal; a detection circuit, for generating a detection result according to a reference voltage and the output voltage; a controllable frequency divider, coupled to the oscillating circuit and the detection circuit, wherein the controllable frequency divider comprises a plurality of frequency dividing ratios and selects one of the frequency dividing ratios according to the detection result, and utilizes the selected frequency dividing ratio to frequency-divide the clock signal to generate a frequency-divided clock signal; and a charge pump circuit, for controlling a charge pump according to the frequency-divided clock signal to generate the output voltage wherein the plurality of frequency dividing ratios of the controllable frequency divider comprises a high frequency dividing ratio and a low frequency dividing ratio; the controllable frequency divider utilizes the low frequency dividing ratio to frequency-divide the clock signal when the reference voltage is larger than the output voltage, and the controllable frequency divider utilizes the high frequency dividing ratio to frequency-divide the clock signal when the reference voltage is smaller than the output voltage.