PHASE-SHIFT FULL-BRIDGE CIRCUIT AND CONTROL METHOD THEREOF

摘要

A phase-shift full-bridge circuit and a control method thereof. The method divides one duty cycle of a phase-shift full-bridge circuit into 10 stages. OA, OB, OC, OD, OE, and OF are the external gate voltages of MOS tubes I to VI (Q1 - Q6) respectively. The method changes simultaneous raising of OE and OC to first and second raising, and changes simultaneous raising of OF and OD to first and second raising, thus making the phase-shift full-bridge circuit realize soft switching under underloading conditions. In a phase-shift full-bridge circuit applying the method, the primary side of the transformer is of a full bridge structure and the secondary side of the transformer is of a synchronous rectification structure. The circuit omits the resonance inductor and clamp diode at the primary side of the transformer, thus reducing system costs, reducing system volume and improving system efficiency.