Low-power Charge Pump Dc / Dc Converter Circuit

High efficiency, low cost and low noise are becoming the development trend of DC/DC regulations due to the popularization of portable equipments powered from battery. In the regulations kinds, charge pump converters use capacitors to store and transfer energy and can work well for step up without the need for an inductor. Therefore, applications that need low or medium power are making charge pump more and more attractive. A low power dissipation charge pump DC/DC converter circuit using 0.5um CMOS technology is presented in this paper. This converter can generate high precise output regulation with wide input voltage range of 2.0V to 5.5V. The input voltage may vary above and below the output voltage and the output will remain in regulation with low output voltage ripple. With the"Skip"modulation technique, quiescent current are reduced to a minimized value of 1mA with full load, 60uA with no load, and less than 0.01uA in shutdown mode. This converter is thermally protected and current limited, protecting the load and regulator during fault conditions.In the circuit design chapter, the basic charge pump operation principle and equivalent circuit model are given first. Then two control modes, pulse skip mode and linear mode, are analyzed. Pulse skip mode is selected to design the whole chip organization and sub block circuit according to the comparison of the two control modes and the requirements of low power dissipation. In the sub block circuit design, the contents that the author had introduced include: the principle of band gap voltage reference and the design technique in low power supply; the analysis of spike pulse noise rejection, frequency divider and dead time in oscillator and control circuit; the selection of the width and length ratio of four switches and 2x/1x mode change point in driver and mode selection circuits.Based on the charge pump principle analysis and circuit design in the beginning chapters, the author simulated all the sub block circuits and whole chip circuit by applying EDA tools HSPICE and Viewlogic. The typical performance characteristics include: line and load transient response, efficiency, output voltage ripple, quiescent current, maximum load current, output voltage temperature characteristics and the short...