【正文】 ode Power SupplySMPS）其功率從零點(diǎn)幾瓦到數(shù)十千瓦不等，廣泛用于生活、生產(chǎn)、科研、軍事等各個(gè)領(lǐng)域。開(kāi)關(guān)電源因其體積小、重量輕、效率高、性能穩(wěn)定等優(yōu)點(diǎn)而逐漸取代傳統(tǒng)的線性穩(wěn)壓電源，被譽(yù)為高效節(jié)能電源，現(xiàn)己成為穩(wěn)壓電源的主導(dǎo)產(chǎn)品。本題目設(shè)計(jì)的開(kāi)關(guān)電源是采用全控型電力電子器件 MOSFET 作為開(kāi)關(guān)，利用控制開(kāi)關(guān)的導(dǎo)通時(shí)間來(lái)調(diào)整輸出電壓，主控制芯片采用 UC3844 實(shí)現(xiàn)電壓電流 雙閉環(huán)控制，采用 PC81 TL431 等專(zhuān)用芯片以及其他的電路元件相配合作為反饋電路，使設(shè)計(jì)出的開(kāi)關(guān)電源具有自動(dòng)穩(wěn)壓功能。 關(guān)鍵詞： 開(kāi)關(guān)電源，反激式變換器，高頻變壓器， UC3844 英 文 摘 要 II Abstract Switching power supply using the PWM, control switch circuit of the power conversion device, it is widely used in AC to DC or DC to DC can transform, usually called the switching power supply (Switched Mode Power SupplyS MPS) power from zeroranging from a few watts to tens of kilowatts,is widely used in various fields of life, production, research, and switching power supply because of its small size, light weight,high efficiency, stable performance and other advantages of gradually replacing traditional linear power supply, known as energy efficient power supply,has now bee the leading product of the power supply. This project is to design a generic multioutput flyback switching power supply,power supply from the 220V mains. Switching power supply design of this topic is the use of fullcontrolled power electronic devices MOSFET as a switch, control switch conduction time to adjust the output voltage, the main control chip UC3844 PC817, of TL431 dedicated chipand patible with other circuit elements as a feedback circuit,voltage and current double closed loop control,the design ofswitching power supply with automatic voltage regulation function. The systemoperating frequency 50kHZ, the output voltage of 7 road isolation. Keywords: switching power supply, flyback converter, highfrequency transformer, UC3844目 錄 III 目 錄 摘 要 .................................................................................................................... ...I ABSTRACT........................................................................................................... ..II 目 錄 .................................................................................................................. .III 第一章 引 言 .....................................................................................................1 課題研究的背景及意義 ............................................................................. 1 開(kāi)關(guān)電源的技術(shù)動(dòng)態(tài) ................................................................................. 2 本課題的主要研究?jī)?nèi)容 ............................................................................. 2 第二章 開(kāi)關(guān)電源的原理 .....................................................................................4 開(kāi)關(guān)電源的基本原理 ................................................................................. 4 開(kāi)關(guān)電源的組成 ....................................................................................... 5 單端反激式拓?fù)浞治? ............................................................................... 5 工作原理 ......................................................................... 5 基本關(guān)系式 ..................................................................... 6 第三章 系統(tǒng)設(shè)計(jì) .................................................................................................9 技術(shù)指標(biāo) ..................................................................................................... 9 黑箱設(shè)計(jì) ..................................................................................................... 9 開(kāi)關(guān)電源電路圖 ....................................................................................... 10 關(guān)鍵元器件的選擇與設(shè)計(jì) ....................................................................... 11 控制器芯片 UC3844 ........................................................11 UC3844 的內(nèi)部結(jié)構(gòu)及管腳功能 ................................. 12 UC3844 的特點(diǎn) .......................................................... 14 線性光耦合器 PC817...................................................... 14 可調(diào)精密并聯(lián)穩(wěn)壓器 TL431 ........................................... 15 高頻變壓器的設(shè)計(jì) ......................................................... 16 目 錄 IV 高頻變壓器作用 ....................................................... 16 高頻變壓器的設(shè)計(jì) .................................................... 17 輸出級(jí)的設(shè)計(jì) ................................................................ 19 功率 MOSFET 及其驅(qū)動(dòng)電路設(shè)計(jì) ................................... 21 功率 MOSFET 的選擇 ............................................... 21 功率 MOSFET 控制電路及其參數(shù)選擇 ....................... 21 電壓反饋電路設(shè)計(jì) ......................................................... 22 電路圖及原理 ........................................................... 22 元器件參數(shù)選擇 ....................................................... 23 輸入啟動(dòng)電路的設(shè)計(jì) ..................................................... 23 輸入整流濾波電路的設(shè)計(jì) ............................................... 24 電路原理圖 .............................................................. 24 元器件參數(shù)選擇 ....................................................... 25 保護(hù)電路的設(shè)計(jì) ........................................................... 25 電路工作過(guò)程總結(jié) ................................................................................... 26 第四章 設(shè)計(jì)總結(jié) ...............................................................................................28 參考文獻(xiàn) .................................................................................