摘要作为新世纪的主打发光器件，LED的应用领域日益扩展，已经在人们的日常生活中产生了明显的影响，而LED使用的核心是LED驱动电源，它的地位随着LED的使用日益重要。

本文首先讲述了反激式变换器的构成和基本原理。作为电气隔离型DC/DC变换器中的一种，反激变换器是中小功率开关电源理想的电路拓扑。其次介绍了原边控制的方法，它能实现在无需副边反馈的情况下恒定副边输出电压和副边输出电流，满足LED的特性需求。基于此，本文选择FL7732芯片作为控制器，并对芯片的功能和工作原理进行了描述。接着，提出了一种基于原边控制单端反激式恒流驱动电路原理，利用FL7732芯片驱动LED的设计电路，具体讲解了参数的设计。最后利用电路模型设计了实物，而后使用示波器调试，得到了比较理想的波形。64364

毕业论文关键词    LED恒流驱动电源  反激式变换器  原边控制  FL7732  

毕业设计说明书（论文）外文摘要

Title    Research and design of the LED constant current  driving power supply                                               

Abstract As the main light emitting device of the new century, LED is increasingly widely used and LED has made great effects on people’s daily lives. LED driving power which is the core of LED application is becoming more and more important.Firstly, this paper describes the composition and the basic principles of the flyback converter. As one of the electrical isolation type in the DC/DC converter, flyback converter is ideal for small and medium - power switching power supply circuit topology. Secondly, the primary side control theory is introduced which achieves constant secondary output voltage and constant secondary output current in the case without the secondary side feedback, satisfying the demand of LED characteristics. Based on this, this paper chooses Chip FL7732 as the controller, and describes its functions and working principles. Then, a LED flyback mode

driving using Chip FL7732 based on the switching power technology is proposed, which contains the parameters’ design. Finally, using the physical design, the ideal waveforms are obtained.

Keywords  LED constant current driving power  flyback converter  primary side control theory  FL7732

1 绪论 1

1.1 题目背景及意义 1

1.2 反激变换器的研究现状 1

1.3 本文的主要内容 2

1.4 本章小结 3

2 LED恒流驱动电源 3

2.1 LED电气特性 4

2.2 LED恒流驱动电源 5

2.3 反激变换器 6

2.4 本章小结 8

3 原边控制的工作原理 8

3.1 恒流原理 9

3.2 恒压原理 11

3.3 FL7732芯片 11

3.4 本章小结 15

4 基于FL7732芯片的单端反激式LED恒流驱动电源设计 15

4.1 设计结构框图 15

4.2 设计电路 15

4.3 测试结果及实物图 25

4.4 本章小结