Capacitive Transposed Series-Parallel Topology With Fine Tuning Capabilities

A general transposed series-parallel topology of a switched-capacitor converter is presented and analyzed in this paper. This topology evolved from the conventional series-parallel through rectangular matrices based topologies to partial arbitrary matrices which are constructed of different size strings of capacitors to arbitrary matrices, based on a bank of equally valued capacitors. Theoretically, these topologies have a large number of dc/dc voltage ratios, which lead to the capability to achieve very accurate fixed dc/dc voltage ratios. These topologies also have the capability for “fine tuning” when voltage regulation is necessary. For the general transposed series-parallel topology, it is shown that the number of possible dc/dc voltage transfer ratios escalates exponentially with an addition of each capacitor as the sum of partition functions. Therefore, relatively fewer components are required for an assumed accurate voltage ratio. Dispersion of parameters in the capacitance value is considered. Small ripple analysis, losses calculations and efficiency considerations are also discussed. Simulations are performed for 2.2 and 2.25 voltage ratios. The simulations are in good agreement with the theoretical calculations.