A high-efficiency CMOS voltage doubler

A charge pump cell is used to make a voltage doubler using improved serial switches. A complete power efficiency theory is presented which fits the measurements. The importance of capacitors is shown with plots of power efficiency versus load and stray capacitors. Several problems arising at low voltage or high frequency are developed and some optimizations are presented. The substrate current is totally suppressed by the technique of bulk commutation. A power efficiency of 95% has been reached using external capacitors. A fully integrated charge pump is also presented and shows a maximum power efficiency of 75%.