摘  要：隨著電力電子技術的發展，開關電源的應用越來越廣泛，人們對其的要求也越來越高，從而促進人們不斷的去探索與發現。其中反激式開關電源由于具有線路簡單，所需元器件少，能夠提供多路隔離輸出等優點，被廣泛應用于小功率電源領域中。本課題在研究開關電源技術發展現狀的基礎上，提出了一個DC-DC多路輸出電路的設計。輸入直流電壓源48V，將直流加到開關變壓器初級上，經高頻變壓器次級感應輸出高頻電壓，經整流濾波供應給負載，從而輸出相應的+5V和+12V穩定電壓，同時輸出部分通過一定的電路反饋給控制電路。用UC3842當做控制芯片來設計出PWM波形發生器，從而實現反激式開關電源，運用該芯片使器件變少的同時還能使電路結構不繁瑣。

關鍵詞：開關電源；DC-DC；多路；反激式；高頻變壓器

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