Method and circuit for improving power supply conversion efficiency of high isolation transformer

The invention discloses a circuit for improving the power supply conversion efficiency of a high isolation transformer. The circuit comprises the high isolation transformer, an output loop, an input power supply, metal-oxide-semiconductor (MOS) tubes Q1 and Q2, and diodes D1 and D2, wherein the secondary of the transformer is connected with the output loop; the drain electrode of the MOS tube Q1 is connected with the positive electrode of the power supply; the source electrode of the MOS tube Q1 is connected with the primary side input end of the transformer; the drain electrode of the MOS tube Q2 is connected with the primary side output end of the transformer and the negative end of the power supply; the cathode of the diode D2 is connected with the positive end of the power supply; the anode of the diode D2 is connected with the drain electrode of the MOS tube Q2; the cathode of the diode D1 is connected with the source electrode of the MOS tube Q1; and the anode of the diode D1 is connected with the negative end of the power supply. Therefore, the MOS tubes Q1 and Q2 can be switched off or switched on at the same time. When the MOS tubes are switched off, energy stored in a leakage inductance mode is released by the diodes and fed back to the input power supply. Therefore, the power supply conversion efficiency is improved, and the reliability of products is increased.