LED恒流电源毕业论文

摘 要

随着电力电子技术的发展，LED由于环保、寿命长、光电效率高等众多优点，近年来在各行各业应用得意快速发展，同时，由于近年来的开关电源在电子电器各行业中占了非常重要的位置，由此驱动LED的开关电源就成了关注热点。

本文通过对LED照明的电压电流特性及几种驱动方式的分析，最终选定采用恒流的方式来设计驱动电源。以达到保证LED的使用安全性、亮度稳定、使用寿命高的目的。本设计由主电路，反馈电路及PWM控制电路组成，主电路通过对输入交流电的整流、滤波、降压、稳压等功能得到输出所需的直流电流，反馈电路检测输出电流的改变，并由PWM控制电路控制场效应管的开断，改变其输出脉冲占空比实现输出电流相对恒定的目的。

关键词：开关电源；恒流；LED驱动电路

Abstract

With the power of the development of electronic technology, LED because of environmental,long life,high efficiency photoelectric many advantages,In recent years in all sectors to rapid application development,while In recent years, the switching power supply in electrical and electronic industries accounted for a very important position. This drives the LED Switching Power Supply concerns have become hot focus.

This paper mainly through analysis of the voltage and current characteristics of LED lighting and the several driven approach，the final selection of a constant current approach to the design driven power. In order to achieve to ensure the security of the use of the LED, the brightness and stability, the life of high purpose. Designed by the main circuit, the feedback circuit and the PWM control circuit, the main circuit by the AC input rectifier, filter, blood pressure, and voltage regulator functions to output the desired DC current, feedback circuit detects the output current changes by PWM control circuit to control the FET switching, changing its output pulse duty cycle is relatively constant output current.

Keywords: Power Supply;Constant current; LED

目 录

第1章 概 述 .......................................................................................................... 1

1.1 LED的发明 .......................................................................................... 1 1.2 LED的工作原理 .................................................................................. 2 1.3 LED照明应用的国内外现状 .............................................................. 3 1.4 LED驱动简介 ...................................................................................... 7

第2章 开关电源原理 ............................................................................................ 9

2.1 原理简介 ............................................................................................. 9 2.2 电路原理 ........................................................................................... 10 2.3 脉宽调制（PWM）技术 .................................................................. 11 2.4 功率因数校正 ................................................................................... 12 2.5 本章小结 ........................................................................................... 13

第3章 硬件电路设计 .......................................................................................... 14

3.1 系统设计框图及工作原理简介 ....................................................... 14 3.2 主要元器件介绍 ............................................................................... 14 3.3 输入电路的设计 ............................................................................... 18 3.4 控制及反馈电路的设计 ................................................................... 19 3.5 输出电路的设计 ............................................................................... 20 3.6 整体电路图 ....................................................................................... 21 3.7 典型性能参数 ................................................................................... 22 3.8 本章小结 ........................................................................................... 22

结 论 ...................................................................................................................... 23 参考文献 ................................................................................................................ 24 致 谢 ...................................................................................................................... 25 附录1 实物图 ....................................................................................................... 26

附录2 系统原理图 ............................................................................................... 27 附录3 PCB图 ....................................................................................................... 28 附录4 元器件清单 ............................................................................................... 29

第1章 概 述

白炽灯时代即将过去了。整个20世纪，爱迪生发明的白炽灯经受住了时间的考验，成为标准的通用照明工具。但新的照明技术－尤其是发光二极管必将最终代替白炽灯和荧光灯LED 这几年发展较快，在大功率照明市场使用LED 越来越变为可能，虽说还不是特别成熟，最少是广众关心的话题之一，照明未来被LED 光源取代将无可置疑。受世界经济影响，都在寻找未来的新的经济增长点，投资LED 方面的资金，会越来越多，加速LED 进程是必然的。LED由于环保，寿命长，光电效率高等众多优点 …… 此处隐藏：13620字，全部文档内容请下载后查看。喜欢就下载吧 ……