The Research On Synchronous Rectification For Push-pull Circuit

In the way of MOS taking place of the Fast recovery diode and the Schottky barrier diode, it can cut down on-resistance and reduce the rectification loss. For the disadvantages of the insufficient driving of the low side switch and the body diode conduction and so on, it can't improve the efficiency farther more.The paper discusses and analyzes several general schemes about synchronous rectification in detail, and studies a gate charge retention synchronous rectification based on the push-pull circuit deeply.The current flows through both parasitic capacitances, charging one while discharges the other in this scheme. It resolves the questions about the body diode conduction and circumfluence in paralleled converters, and increases the efficiency. Based on the push-pull topology, using double-current rectification in secondary part, it can wide the appliance scope, decrease the difficulty of manufacturing transformers and achieve high efficiency converters.High quality to the coupling between all the windings, it can prevent the abnormal phenomenon on gate-source, not a negative voltage, but a positive voltage. Through theoretical analyses and simulations, the paper provides the scheme of keeping good-coupling to the transformer. It also discusses the topology of multi-output and the design of parameters.The theoretical analysis is verified by the experimental sample, data and waveforms.