摘  要：随着电力电子技术的发展，开关电源的应用越来越广泛，人们对其的要求也越来越高，从而促进人们不断的去探索与发现。其中反激式开关电源由于具有线路简单，所需元器件少，能够提供多路隔离输出等优点，被广泛应用于小功率电源领域中。本课题在研究开关电源技术发展现状的基础上，提出了一个DC-DC多路输出电路的设计。输入直流电压源48V，将直流加到开关变压器初级上，经高频变压器次级感应输出高频电压，经整流滤波供应给负载，从而输出相应的+5V和+12V稳定电压，同时输出部分通过一定的电路反馈给控制电路。用UC3842当做控制芯片来设计出PWM波形发生器，从而实现反激式开关电源，运用该芯片使器件变少的同时还能使电路结构不繁琐。

关键词：开关电源；DC-DC；多路；反激式；高频变压器

Abstract：With the development of power electronics, the application of switching power supply become more and more widely. And the people's requirements about it becomes higher than before. It promotes people to discover and explore continuously. Flyback switching power supply is widely used in the field of low power. Because its circuits are simple, required components are less and it can provide multiple isolated outputs. This paper puts forward a design of DC-DC multiple outputs circuit based on the research of the developing situation of switching power supply. We input DC voltage source 48V, add DC to primary switching transformer, output high-frequency output voltage through the high-frequency transformer sub-prime induction, supply load via rectifier filter. Then it outputs corresponding stable voltage of +5V and +12V. Meanwhile, it outputs some part to feedback to control circuit through certain circuit. We use UC3842 as Control IC to design a PWM waveform generator for the realization of flyback switching power supplying. The use of UC3842 not only less the amount of components, but also make the circuit structure simple.

Key-Words：switching power supply; DC-DC; multiple; flyback; high-frequency transformer