光強可調LED照明電源設計

應用物理學論文編號:WLX109  字數:12932,頁數:21

目  錄
中文摘要i    
英文摘要．．ii  目錄iii   
第1章     緒論．．1
 1.1  研究的動機、目的及意義．．1
 1.1.1  研究的動機與目的．1
 1.1.2  研究的意義．1
 1.2  研究背景1                            
 1.2.1  LED照明現狀．．1
 1.2.2  LED驅動電源研究狀況2
 1.3  論文內容概述．．2
第2章     LED光源及其驅動簡介．3
 2.1  LED發光原理及其I-V特性3
 2.2  LED驅動電路．．3
 2.2.1  LED驅動器的特性．3
 2.2.2  DC/DC變換器及其拓撲結構．．3
第3章     LED驅動電路設計．．6
 3.1  LED驅動電路設計要求6
 3.2  降壓型DC/DC變換器集成電路芯片的選取．．6
 3.2.1  芯片的初步選取6
 3.2.2  三種芯片性能比較．7
 3.2.3  驅動電路控制芯片LM2575介紹．．7
 3.3  LED驅動電路原理圖設計及其工作原理介紹8
 3.3.1  LED驅動電路原理圖設計．8
 3.3.2  驅動電路外圍元器件的選取．．9
 3.3.3  LED驅動電路工作原理．．10
第4章     LED驅動電路硬件制作、調試、測試與分析．．12
 4.1  硬件制作與調試．．12
 4.1.1  硬件制作．．12
 4.1.2  電路調試．．12
 4.2  電路性能測試與分析．12
 4.2.1  穩流分析．．12
 4.2.2  光強可調分析．13
第5章     結束語．14
致謝．．15
參考文獻．16

摘    要
 
 發光二極管（Light Emitting Diode，LED）作為一種固體光源，因其節能、環保、結構牢固、壽命長、啟動時間短、體積小、低壓驅動等諸多特性，應用前景十分巨大，因此對LED驅動電路的研究有著重要的理論意義和應用價值。本課題針對線性穩壓電源功耗大、體積大的不足，設計了一種體積小、效率高、性能穩定、價格便宜的脈沖寬度調制(Pulse Width Modulation，PWM) 開關電源，用以恒流驅動LED，并可通過外部電位器改變輸出電流，以達到光強可調的目的。本論文首先說明了研究的動機、目的、意義及其背景，然后根據LED的電氣特性、LED驅動器的特性及系統要求，選擇降壓(Buck)式DC/DC變換器拓撲結構，使用LM2575-ADJ作為系統核心控制芯片，設計了一種在15 V～30 V輸入電壓下輸出電流可在8 mA～40 mA之間變化的開關電源，本文詳細說明了具體的設計過程，硬件制作及調試方法，經測試分析證明該電源基本滿足恒流驅動LED的設計要求。 
關鍵詞：  發光二極管  脈沖寬度調制  開關電源  恒流驅動  降壓式DC/DC變換器

Abstract
 
 LED（Light Emitting Diode）is a solid light source , it has an enormous application prospect because of its advantages , such as energy conservation, environmental protection, firm structure, long life, short start-up time, small volume, low voltage supply. So research of LED Drive Circuit has crucial significance of theory and value of application. Due to the disadvantages of the Linear Regulated Power Supply which has high power consumption and large volume, a PWM(Pulse Width Modulation) switch power supply has been designed with the characteristics of small volume, high efficiency, steady performance, low cost, used to drive LED by constant current which can be adjusted by regulating external potentiometer, and the light intensity also changes. Firstly this paper introduces the motivation, the purpose, the significance and the background of the research, then selects Buck topology DC/DC converter based on the study of the electrical characteristics and the driver’s characteristics of LED and the system requirements, takes LM2575-ADJ as the core control chip of the system, it designs a switch power supply which can convert 15 V～30 V DC power supply into 8 mA～40 mA DC output current. In this paper, the design process, the hardware making and the debugging methods of the system are introduced in detail. It proves that the power supply basically satisfied the requirement of constant current driving LED through testing and analyzing.
Keywords： LED  PWM  switch power supply  constant current driving  Buck DC-DC converter