Analysis and Optimization of Switched-Capacitor DC-DC Converters

• Published in: IEEE transactions on power electronics Vol. 23; no. 2; pp. 841 - 851
• Main Authors: Seeman, M.D., Sanders, S.R.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.03.2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analysis; Analytical models; Applied sciences; Capacitance; Capacitors; Capacitors. Resistors. Filters; Circuit properties; Circuits; Constraint optimization; dc-dc converter; DC-DC power converters; Dielectric, amorphous and glass solid devices; Electric currents; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electronic circuits; Electronics; Exact sciences and technology; Impedance; Methods; output impedance; Performance analysis; Power electronics, power supplies; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Signal convertors; Steady-state; switched-capacitor; Switches; Switching converters; Various equipment and components; Magnetic circuit convertor; Performance evaluation; dc-dc converter; Direct current convertor; Optimization method; switched-capacitor; Power capacitor; Output impedance; Experimental study; DC-DC power convertors; Steady state; Switching; Optimization; Analysis method; Analysis; Capacitance; Electric loss; System simulation; Selector switch; Comparative study; Energy storage
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2007.915182

Analysis methods are developed that fully determine a switched-capacitor (SC) dc-dc converter's steady-state performance through evaluation of its output impedance. This analysis method has been verified through simulation and experimentation. The simple formulation developed permits optimization of the capacitor sizes to meet a constraint such as a total capacitance or total energy storage limit, and also permits optimization of the switch sizes subject to constraints on total switch conductances or total switch volt-ampere (V-A) products. These optimizations then permit comparison among several switched-capacitor topologies, and comparisons of SC converters with conventional magnetic-based dc-dc converter circuits, in the context of various application settings. Significantly, the performance (based on conduction loss) of a ladder-type converter is found to be superior to that of a conventional magnetic-based converter for medium to high conversion ratios.