A modified Dickson’s charge pump circuit with high output voltage and high pumping efficiency

Abstract

A modified Dickson’s charge pump circuit with high output voltage and high pumping efficiency fabricated by IHP’s 130 nm SiGe BiCMOS process is proposed. Instead of traditional on-chip metal–insulator–metal capacitor, a modified vertical parallel plate capacitor is utilized as the pumping capacitor, which owns a breakdown voltage higher than 84 V and an improved capacitance density of 1.92 fF/μm2. Thus, the output voltage and chip size of charge pump circuit are not limited by the pumping capacitor. To further improve the voltage pumping efficiency and make the circuit suitable for low voltage operation, the threshold voltage and the body effect coefficient is eliminated by using a dynamic control to both the charge transfer switches and the MOSFETs body voltages. Simulated result of a 35-stage charge pump circuit with an output voltage higher than 100 V is demonstrated. A 7-stage charge pump circuit with an output voltage of 13.8 V and a pumping efficiency of 75%, higher than the traditional Dickson’s charge pump circuits, is fabricated and measured.