7路输出单端反激式开关电源设计大学毕业设计（论文）.doc

7路输出单端反激式开关电源设计 7 outputs single-ended flyback switching power supply design thesis a 摘 要 开关电源是一种采用PWM等技术控制的开关电路构成的电能变换装置，它广泛应用于交直流或直直流电能变换中，通常称其为开关电源（Switched Mode Power Supply-SMPS）其功率从零点几瓦到数十千瓦不等，广泛用于生活、生产、科研、军事等各个领域。开关电源因其体积小、重量轻、效率高、性能稳定等优点而逐渐取代传统的线性稳压电源，被誉为高效节能电源，现己成为稳压电源的主导产品。 本课题是设计一个通用的多路输出的反激式开关电源，电源取自220V市电。本题目设计的开关电源是采用全控型电力电子器件MOSFET作为开关，利用控制开关的导通时间来调整输出电压，主控制芯片采用UC3844实现电压电流双闭环控制，采用PC817、TL431等专用芯片以及其他的电路元件相配合作为反馈电路，使设计出的开关电源具有自动稳压功能。系统工作频率为50kHz，输出7路隔离的电压。 关键词：开关电源，反激式变换器，高频变压器，UC3844 Abstract Switching power supply using the PWM, control switch circuit of the power conversion device, it is widely used in AC to DC or DC to DC can transform, usually called the switching power supply (Switched Mode Power Supply-S MPS) power from zeroranging from a few watts to tens of kilowatts,is widely used in various fields of life, production, research, and military.The switching power supply because of its small size, light weight,high efficiency, stable performance and other advantages of gradually replacing traditional linear power supply, known as energy efficient power supply,has now become the leading product of the power supply. This project is to design a generic multi-output flyback switching power supply,power supply from the 220V mains. Switching power supply design of this topic is the use of full-controlled power electronic devices MOSFET as a switch, control switch conduction time to adjust the output voltage, the main control chip UC3844 PC817, of TL431 dedicated chipand compatible with other circuit elements as a feedback circuit,voltage and current double closed loop control,the design ofswitching power supply with automatic voltage regulation function. The systemoperating frequency 50kHZ, the output voltage of 7 road isolation. Keywords: switching power supply, flyback converter, high-frequency transformer, UC3844目 录 摘 要 I Abstract II 目 录 III 第一章 引 言 1 第二章 开关电源的原理 3 2.1 开关电源的基本原理 3 2.2 开关电源的组成 4 2.3 单端反激式拓扑分析 4 2.3.1 工作原理 4 第三章 系统设计 6