A DC-DC Charge Pump Based on Voltage Doublers

A new organization of switched capacitor charge pump circuits based on voltage doubler structures is presented in this paper. Each voltage doubler takes a DC input and outputs a doubled DC voltage. By cascading n voltage doublers the output voltage increases up to 2 times. A two phase and a multiphase voltage doubler structures are proposed and their properties discussed. The multiphase voltage charge pump is a minimum capacitance realization of the switched-capacitor based voltage multiplier. A simulator working in the Q-V realm was used for simplified circuit level simulation and to estimate the number of required clock cycles to pump the output to a desired voltage. In order to evaluate the power delivered by a charge pump, a resistive load is attached to the output of the charge pump and an equivalent capacitance is evaluated. Power analysis is performed using an equivalent R-C circuit. A comparison of the proposed circuits with Dickson charge pump and Makowski’s voltage multiplier is presented in terms of the area requirements, the voltage gain, and the power level. This paper also shows the results of computer simulation that identifies optimum loading conditions for different configurations of the charge pumps. Design guidelines for the desired voltage and power levels are discussed.