Low-volume stackable flyback converter with near minimum deviation controller

This paper introduces a flyback-based low-volume modular converter and complementary mixed-signal controller that provide input voltage and output current sharing as well as near optimal transient response. This serial-input paralleloutput switch-mode power supply (SMPS) is well suited for high-step down ratio applications where, compared to a conventionally used multi-phase buck, it requires a smaller output filter volume, lower MOSFET blocking voltages, and provides better dynamic response. The stackable flyback also has better power processing efficiency and provides inherent passive current sharing. These advantages are achieved by utilizing low-voltage flyback cells and a novel implementation of minimum deviation control method. Experiments with a 12-to-1-V, 4-A, 500kHz 2-cell stacked flyback converter prototype show that, compared to an equivalent 12-V 2-phase conventional buck with approximately the same inductor volume, the introduced converter has 14% smaller output capacitor, up to 40% lower power losses, and 33% faster transient response.