A 45-ratio recursively sliced series-parallel switched-capacitor DC-DC converter achieving 86 efficiency

摘要

A Recursive Ternary switched-capacitor (RT-SC) topology that achieves more than 3(3-1)/2 ratios with N SC cells is presented. To achieve the high number of ratios for a wide output voltage range, a three-ratio (1/3, 1/2, 2/3) Series-Parallel (SP) topology is sliced into N reconfigurable three-ratio SP sub-cells that are interconnected in a series or stacked configuration in order to realize a minimum voltage-conversion resolution of Vin/6. Importantly, this modular approach supports a recursively defined topology, by operating the three-ratio SP sub-cells in parallel the high efficiency at large power density of a standard three-ratio SP converter is achieved. The proposed RT-SC converter realizes ternary m3/3 conversion ratios as well as binary m2/2 and mixing m6/6 modes. A 45-ratio fully-integrated RT-SC is fabricated in a 0.25μm CMOS process, achieving 53% larger output operating range than a conventional three-ratio SP at 0.5mA/mm, and 15% higher efficiency than a Recursive Binary SC at 3.4× larger current density.