Analysis and Design of Half-bridge Dickson Resonant Switched-Capacitor Converters With “Indirect” Resonant Core

The traditional Dickson switched-capacitor converters (SCCs) come with the shortcomings of high transient current spike, hard-switched operation and limited voltage gain range. In this article, through analyzing the sneak circuit paths, half-bridge Dickson resonant SCCs (HB Dickson RSCs) with “indirect” resonant core are operated and designed in the optimal region where the switching frequency is above resonance. The converters feature soft charging operation, eliminating the high current spike. All transistors achieve zero-voltage-switching turn-on and all diodes have zero-current-switching turn-off. In addition, the voltage-gain range of the HB Dickson RSCs can be expanded significantly and the voltage stress on transistors remains low, equal to the input voltage. An extensive analysis of three operation modes, voltage gain variation range, soft-switching constraints, boundary conditions and component stress is presented to reveal the optimal operation region for 3X(i.e. 3 times) and NX(i.e. N times) HB Dickson RSCs. The optimal operation region is obtained to assist converter operation and hardware design for input/output voltage fluctuation applications. A 24V/29~69.6 V 3X HB Dickson RSC prototype rated at 23-100W with a peak efficiency of 97.8% was designed and built under the hardware guideline. The analysis is verified by experimental results.