毕业论文《LED恒流电源》.doc

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 TOC \o 1-2 \h \z \u HYPERLINK \l _Toc327272506 第1章 概 述 PAGEREF _Toc327272506 \h 1 HYPERLINK \l _Toc327272507 1.1 LED的发明 PAGEREF _Toc327272507 \h 1 HYPERLINK \l _Toc327272508 1.2 LED的工作原理 PAGEREF _Toc327272508 \h 2 HYPERLINK \l _Toc327272509 1.3 LED照明应用的国内外现状 PAGEREF _Toc327272509 \h 3 HYPERLINK \l _Toc327272510 1.4 LED驱动简介 PAGEREF _Toc327272510 \h 7 HYPERLINK \l _Toc327272511 第2章 开关电源原理 PAGEREF _Toc327272511 \h 9 HYPERLINK \l _Toc327272512 2.1 原理简介 PAGEREF