Steady-state analysis of zero-voltage transition large step-down buck converter

A zero-voltage transition large step-down buck converter is proposed in this paper. It provides larger step-down voltage ratio together with soft transition to one of the switch during turn-ON process. Furthermore, it transfers power to load at reduced current ripple, which is smaller in comparison to the conventional buck converter source current ripple. A pseudo zero-voltage transition cell is introduced to achieve soft-switching feature during turn-ON transition to one of the switches. This cell not only results in ZVT performance to the main switch, but also gives zero-current transition features to all the diodes present in the converter. Various operating modes of the circuit are identified and then steady-state time-domain analysis is established. Necessary and sufficient conditions for ensuring soft-switching are derived. To demonstrate the effectiveness of the proposed zero-voltage transition converter, PSIM simulations are carried out and then verified through experiments. A 48 to 12 V, 50 kHz low power prototype is use for experimentation. Measured and theoretical predicted results are in close agreement with each other.