Isolated Two-Transistor Zeta Converter With Reduced Transistor Voltage Stress

This brief introduces an isolated two-switch Zeta dc-dc converter, along with the steady-state analysis and experimentation. The high transistor voltage stress due to the ringing caused by the resonance of the transformer leakage inductance and the transistor output capacitance is a major drawback in the conventional isolated Zeta converter. With the incorporation of an additional transistor and two clamping diodes on the primary side of the transformer of the isolated Zeta converter, an isolated two-transistor Zeta converter is proposed. In the proposed converter, the voltage stress of both transistors is reduced to the dc input voltage VI. Experimental results from a 10-V/30-W 100-kHz laboratory prototype is presented to validate the theoretical analysis.