Non-isolated Inductor-less Soft-Switching Bus Converter with Self-Driven

This invention proposes a simple topology for the first stage of non-isolated two-stage applications. The output inductor is eliminated. The magnetizing current is used to achieve ZVS for all switches. By choosing leakage inductance and output capacitance carefully, the turn-off current for the primary switch is very small and ZCS is achieved. Most importantly, the body diode loss is eliminated. A prototype is built to verify the theoretical analysis. Its efficiency is as high as 96% at 1MHz switching frequency. Compared with conventional PWM Buck, it can increase power density by 2.5 times.

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