Development of multiple output operation based on single stage switched-capacitor resonant converters

Power converters are commonly based on the switched mode techniques which use pulse-width modulation to control the converters. Switching loss and switching noise restrict high frequency operation such as more than 200 kHz. The resonant converter is a solution of the above problem. The resonant converter enables switching devices to operate under zero-current or zero-voltage switching. The main disadvantage is that the parasitic effect is very difficult to handle and the transistors may not work at zero-voltage/current switching through the whole range of operation. A family of switched-capacitor circuits using two transistors is presented to overcome the above problems. This family only requires a very small inductor for resonance and therefore is suitable for hybridization. It has variable topologies, which provide different voltage conversion ratios. Each topology can be merged to produce multiple outputs easily that is very difficult to perform when classical switched-mode or resonant converters are used. This paper investigates the feasibility of this circuit merger technique. Experimental and theoretical analyses are presented. Results confirm that the converter operates under zero-current switching. The circuit is simple and multiple outputs can be obtained by simply connecting the switching capacitor states together. Experimental results have confirmed that the converter can produce high conversion efficiency. This paper presents the double inverting, double step-up, and inverting and step-up circuits.