Research On Low Voltage High Current Forward Converters

With the development of microprocessor and digital signal processor(DSP), lower output voltage and higher current is needed to provided. Therfore,research on lower output voltage and higher current forward converter is widely focμsed on.Firstly, the principle of traditional active clamp forward converter introduced and the soft switching conditions of main switches for forward converters in this paper.Secondly, a sub-resonant active clamp circuit is proposed. By analyzing the operating principles of this circuit, it can be seen that it is much better than those traditional active clamp forward converters on conditon of soft switching process.Thirdly, the concept of synchronoμs rectifier is introduced and the suggestion of synchronoμs rectifier circuit applied in sub-resonant active clamp circuits is given.The operating process of this circuit is analyzed in detail.Finally, the design method of forward converter for sub-resonant active clamp and synchronous rectifier circuits is discussed in depth.Simulation is carried out on the theories proposed with OrCAD software, and a protype of synchronous rectification sub-resonant active clamp forward converter is designed out. The simulation and experimental results verify the validity of theoretical analysis and this design method.