A high efficiency charge pump with continuous frequency charge sharing scheme

In this paper, the charge pump efficiency is discussed, and a charge pump with continuous frequency charge sharing scheme is presented. The proposed charge sharing clock generator is able to recover the charge from parasitic-capacitor charging and discharging, so that the dynamic power loss is reduced by half. Furthermore, the proposed frequency regulation structure is able to keep the efficiency of charge pump at the theoretical maximum value without effect of load current. The simulation results show a maximum 10% efficiency increase and the efficiency is kept around 68% when load current decreases, while efficiency of conventional charge pump drops to 23% when load current is 10uA.