Design Of Asymmetrical Half Bridge Switching Power Supply Based On Soft-switching Technology

The asymmetrical half bridge switching power supply based on soft-switching technology is the innovation of balanced half bridge switching power supply. Compared with the balanced half bridge switching power supply, the asymmetrical half bridge switching power supply has several merits. For example, it can craftily use the transformer leakage inductor and the intrinsic parasitic elements of the switch components to realize the zero switching process; it use less components, which is propitious to reduce volume of switching power supply and enhance reliability of the power; and it is also propitious to realize soft switching process and raise complete machine efficiency of the power.There are several parts, which include the design of main circuit, high frequency transformer, driving circuit, voltage feedback circuit, over current protection circuit and over temperature protection circuit, in the inverse power supply designed by this article. Because of the particularity circuit topology, the design of driving circuit is the innovation and the difficulty of this article. Driving circuit applies not only the PWM generator of traditional TL494, but also pulse generator of new MC33153.Both of them make the driving force more formidable.In recent years, the concept of power "green" is advanced at home and abroad, and how to improve the PF becomes an important element of the switching power supply design. This article designs a Power Factor Correction circuit basing on UC3854, whose control circuit adopts average current method and the topology structure adopts Boost circuit. The power factor can be up to 0.99.To make the system more perfect, the paper joins the human-computer interaction module. The module uses a microcontroller as the control core to active output parameters displaying on the LCD and over-current protected. The human-computer interaction module includes:Output voltage and current signal sampling, A/D conversion and data processing, keyboard processing and LCD liquid crystal display.