Analysis and Optimization of Switched Capacitor Power Conversion Circuits With Parasitic Resistances and Inductances

For a switched-capacitor converter (SCC) built by discrete components, its performance is inevitably influenced by parasitic resistances and stray inductances. A basic SCC unit including parasitic resistances and stray inductances behaves as an RLC series circuit operated in charging and discharging states alternatively. Hard-switching SCC with small Q factor, due to the small stray inductance, is analyzed based on overdamping RLC circuit theory. And the underdamping RLC series network is used to analyze soft-switching SCC whose Q factor is greater than 0.5. New mathematical equations are derived to evaluate the impact of parasitic resistances and inductances on the performance of SCCs. Following that, the corresponding design methodologies are proposed for both hard- and soft-switching SCCs. The effectiveness of the proposed analysis and design methods are experimentally demonstrated by a 300-W double-mode SCC prototype.