张明志
淮北师范大学物理与电子信息学院 235000
摘要 本设计是基于TL431设计反馈电路的一种反激式开关电源。反激式开关电源的优点是其电路简单、体积小便于携带、输出电压稳定性高。 随着信息技术的迅速发展，反激式开关电源适用于小功率场合且易于推广使用。本电源设计主要讲述了开关电源的基础知识和反激式开关电源的基本原理设计、集成芯片的使用和外围电阻的确定、由TL431和PC817构成的反馈电路及课题研究得出的结果。 文讲述了利用反激式开关电源的基本原理设计出了供非常规用电设备使用的非常规开关电源，课题研究结果得出它的输出电压稳定性高，且输出电流大，具有实用性。同时，我们还可以根据本论文的设计原理通过改变占空比和芯片外围电阻值制作不同输出的开关电源（输出功率要在100W以内），供应日常生活的小功率电器使用。
关键词 开关电源；反激式；本振频率TL431；UC3842；反馈电路
The flyback type switch power supply design based on TL431
精油与肌肤百度影音
Zhang Mingzhi
School of Physics and Electronic Information, Huai Bei Normal University, Anhui Huaibei, 235000空调衣
Abstract A high precise and reliable single-ended flyback switching power supply was designed and made in this paper,whose current controller consisted of alinear photoelectric couple. The closed-loop feedback of TL431 was used to realize switching power supply’s stable equilibrium.Compared with general switching power supply, the power’s had been with the advantages of high switch frequency,small switch loss, high reliability and so on.With the rapid development of Information Technology,the flyback switching power supply was used widely in low power application.The design and application of a new single-output single flyback switching power supply was proposed in this paper.The paper had been analyzed flyback switching power supply of their working principle and the basic k
nowledge ,and introduced a few major chip functions and the use of the pin and the research results.Of course,the realization of the feedback circuit based on TL431 and PC817 was presented in the paper.An unconventional-output and single-ended flyback switching power supply was designed and made in this paper,whose the basic principle consists of the flyback type switch power supply.The article had been introduced an unconventional flyback power supply.The flyback power supply had been with the advantage of output current large and stable voltage.Concurrently, we can also use the small power electrical appliances in the daily life,which we will make according to the principle of the flyback switching power supply in this power.
Keywords Switching power supply;Flyback;TL431;UC3842;feedback circuit
目次
1 绪论…………………………………………………………1
1.1 开关电源简介…………………………………1
1.2 开关电源基本原理……………………………2
2 基于TL431的反激式开关电源设计………………………4
2.1 TL431简介庞大内部资源网……………………………………4
2.2 PC817简介……………………………………6
3 反激式开关电源设计………………………………………8
3.1 反激式开关电源主电路频偏………………………8
3.2 反馈电路………………………………………11
3.3 电路检测………………………………………14
3.4 辅助电源………………………………………20
4 三维试衣测试方法与数据……………………………………………21
4.1 测试方法与数据…………………………………21
结论……………………………………………………………23
参考文献……………………………………………………………24
致谢…………………………………………………………… 25
1 绪论
1.1 开关电源简介
整个通信系统的动力源是开关电源系统，开关电源系统也被称为通信系统的“心脏”，可见他占有极其重要的地位。随着我国电子技术高速、迅猛的发展，越来越离不开开关电源，，同时对开关电源的精度要求也越来越高。
开关电源是开关稳压电源的简称，它是一种由周期性通断开关来实现控制开关电源占空比从而调整输出电压的用脉宽调制驱动功率半导体器件的电源电路[1]。开关电源采用功率半导体器件作为开关器件，通过周期性间断工作，控制开关器件的占空比来调整输出电压。
开关电源的基本构成DC/DC变换器进行功率转换，它是开关电源的核心部分，此外还有启动、过流与过压保护、噪声滤波等电路。输出采样电路由TL431芯片检测输出电压变化，与基准电压比较，误差电压经过放大及脉宽调制（PWM）电路，再经过驱动电路控制功率器件的占空比，从而达到调整输出电压大小的目的。
