Flying capacitor design considerations for a 48-to-12 V, 35 a split-phase dickson SC converter

Switched-capacitor converters can deliver better performance, power density, and switch utilization compared to inductor-based power converters, but they suffer from current spikes during switching due to capacitor charge redistribution. This can be solved by methods such as split-phase control, which was developed to address charge redistribution in Dickson SC converters by controlling the charging and discharging of the circuit's flying capacitors, such that the equivalent branch voltages line up when the circuit switches states. However, split-phase control is most effective at compensating for charge redistribution when all the circuit's flying capacitors are matched in capacitance value. Differences between the capacitance values of the circuit flying capacitors may result in split-phase control not being able to fully compensate for charge redistribution, due to the different charge/discharge rates of the flying capacitors. The work presented in this paper provides an in-depth analysis of the sensitivity of the split-phase Dickson converter to mismatches in flying capacitor values, as well as discussions regarding the design considerations and prototype test results of a split-phase Dickson converter for high-current loads.