A dynamic analysis of the Dickson charge pump circuit

Dynamics of the Dickson charge pump circuit have been analyzed. The analytical results enable the estimation of the rise time of the output voltage and that of the power consumption during boosting. By using this analysis, the optimum number of stages to minimize the rise time has been estimated as 1.4 N-min, where N-min is the minimum value of the number of stages necessary for a given parameter set of a supply voltage, threshold voltages of transfer diodes, and a boosted voltage. Moreover, the self-load capacitance of the charge pump, which should be charged up at the same time as the output load capacitance of the charge pump, has been estimated as about one-third of the total charge pump capacitance. As a result, the equivalent circuit of the charge pump has been modified. The analytical results have been in good agreement with the simulation results by the iteration method, typically within 10% for the rise time and within 2% for the power consumption. In case of a charge pump with MOS transfer transistors, the analytical result of the rise time has agreed with the SPICE simulation within 10%.