A theoretical charge transfer scheme for efficiency optimization of integrated charge pumps

A scheme which provides optimized charge transfer for integrated charge pumps is presented. The pump capacitors in the intermediate stages of the pump are split into k smaller capacitors C/k. Higher charge transfer efficiency is achieved by sequentially transferring charge packets from a capacitor C to each of the cascaded k capacitors C/k and, then, by sequentially connecting each of these k capacitors to a cascaded stage capacitor C. Mathematical analysis and circuit simulations show that a charge pump based on the proposed method features reduced output resistance with respect to conventional solutions which results in higher power efficiency, thus making the proposed scheme very well suited to low-power devices.