Low Power, Non-Isolated, Extremely-High Step-Up, Quasi-Resonant Hybrid dc–dc Converter

This paper introduces a low-power, non-isolated, step-up quasi-resonant converter and a complementary mixed-signal controller. The introduced converter is capable of generating conversion ratios exceeding 50x, while maintaining high power processing efficiency. At low power levels, ranging from a fraction of a watt to a few watts, conventional ultra-high step-up solutions operate at efficiencies that are not exceeding 45%, mostly limited by switching losses. The introduced solution exhibits efficiencies exceeding 70%. The improvements are achieved by strategically incorporating a N-stage charge pump with a previously introduced fully soft-switching quasi-resonant boost converter. The solution exhibits load-independent soft-switching for all the active switches, at all voltage conversion ratios. The operation and performance of the introduced converter are experimentally verified with a discrete prototype with input voltage 3.6 V, boosting it to high output voltages ranging from 55 V to 250 V, while supplying load currents ranging from 1 mA to 20 mA and achieves peak efficiency of around 85%.