| Summary: | A cascaded-like high-step-down converter (CHSDC) is proposed in this article, which can steeply convert a high voltage to a much lower level without the utilizing of extreme turns ratio or duty ratio. The proposed converter integrates two buck-boost converters and one forward converter to form a single-stage architecture containing only a single low-side driving switch, which, as a result, can lower the cost and reduce the complexity of the associated control driver. Even in a single-stage single-switch structure, the ability to step down input voltage is as effective as the cascade of two buck-boosts and one forward converter. Meanwhile, the proposed converter can avoid the low efficiency caused by a cascaded structure. Without an additional clamp circuit, the leakage energy stored in the transformer of the CHSDC can be still recycled so as to raise the efficiency of the converter and suppress voltage spikes at the power switch. Converter operation principle and key parameter design are discussed. Moreover, a 200 W prototype is built and then tested to validate the proposed converter and verify the theoretical analysis.
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