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河南科技大学毕业设计（论文）I论文基于TL494的微机开关电源设计摘要随着开关电源在计算机、通信、航空航天、仪器仪表及家用电器等方面的广泛应用,人们对其需求量日益增长,并且对电源的效率、体积、重量及可靠性等方面提出了更高的要求。开关电源以其效率高、体积小、重量轻等优势在很多方面逐步取代了效率低,又笨又重的线性电源。电力电子技术的发展,特别是大功率器件IGBT[1]和MOSFET的迅速发展,将开关电源的工作频率提高到相当高的水平,使其具有高稳定性和高性价比等特性。开关电源技术的主要用途之一是为信息产业服务，信息技术的发展对电源技术又提出了更高的要求,从而促进了开关电源技术的发展。微机的电源通常采用脉宽调制式开关稳压电源，这种电源具有功耗小、转换效率高、工作可靠、保护完善和稳压范围宽等特点，开关电源的高频变换电路形式很多,常用的变换电路有推挽、全桥、半桥、单端正激和单端反激等形式。本课题介绍了一种基于PWM[2]技术的半桥式微机开关稳压电源，它是通过用双端驱动集成电路——TL494输的PWM脉冲控制主开关的导通来控制直流输出的。本文给出了微机开关稳压电源的交流输入整流滤波电路、辅助电源电路、PWM控制及驱动电路,多路直流输出电路、自动稳压控制电路的详细设计方法及设计思路，并附有详细的电路图。关键词：IGBT，PWM，开关电源，驱动电路，整流河南科技大学毕业设计（论文）IIDESIGNOFAMICRO-COMPUTERSWITCHINGPOWERSUPPLYBASEDONTL494ABSTRACTWiththedevelopmentofswitchingpowersupplyinthefieldofcomputer,correspond,aviationandastronautics,instrumentappearanceandelectricalproductionetc,thedemandoftheproductionareincreasingaspeopleneed,andpeoplehavebroughtforwardhigherrequesttoaspectsuchasthepowerefficiency,bulkfactor,andreliability.Theswitchpowernotonlyvolumeissmallbutalsoefficiencyisheight,weightmakeslight,whicharesubstitutingtheinefficient,bothstupidandseriouslinearitypowerinmanyaspectsstepbystep.Withtheelectricpowerelectronictechnologydevelopment,especiallyhighefficiencydeviceofIGBTandtheMOSFETrapiddevelopment,theswitchingpower’sperformancedevelopvariousanditscostisbecomingcheaperandcheaper,peoplecouldacceptthenewswitchingpower.Theinformationtechnologydevelopmentalsosetahigherrequesttothepowersourcetechnology,thuspromotedtheswitchingpowertechnologydevelopment.Themicrocomputerpowerusuallyadoptspulsewidthmodulationswitchingpowersupply.ThissubjectintroducesakindofPWMtechnologybasedonhalfbridgetypemicrocomputerswitchingpowersupply.ItisthroughtheuseofdriveICTL494controlofthepulseofPWMswitchconductiontocontroldcoutput.Inthispaperthemicrocomputerswitchingpowersupplyfiltercircuits,auxiliarypower,PWMcontrolanddrivecircuit,multi-channelDCvoltageoutputcircuit,automaticcontrolcircuitofdetaileddesignmethodanddesignideas,anddetailedcircuit.KEYWORDS:IGBT，PWM，switchingpower,drivecircuit，rectify河南科技大学毕业设计（论文）III目录前言................................................................................................1第1章开关电源的发展...................................................................21.1开关电源概述.......................................................................21.1.1开关电源的工作原理.................................................21.1.2开关电源的组成.........................................................31.1.3开关电源的特点.........................................................41.2开关电源的分类...................................................................41.3开关器件的分析...................................................................51.3.1开关器件的特征.........................................................51.3.2电力二极管.................................................................61.3.3电力场效应晶体管MOSFET.........................................6第2章主要开关变换电路...............................................................82.1推挽开关变换电路...............................................................82.2半桥开关变换电路...............................................................92.2.1半桥开关变换电路工作原理......................................92.2.2半桥变换器的应用...................................................10第3章TL494在微机开关电源中的应用......................................123.1TL494概述..........................................................................123.1.1TL494主要特性.......................................................123.1.2TL494工作原理简述................................................123.1.3TL494内部电路结构................................................133.2TL494的各脚功能及参数..................................................143.3TL494脉冲控制波形图.....................................................153.4TL494构成的PWM控制器电路..........................................16第4章微机开关电源的原理与组成..............................................194.1微机开关电源的原理.........................................................194.2微机开关电源的组成.........................................................204.2.1交流输入整流滤波电路............................................20河南科技大学毕业设计（论文）IV4.2.2脉冲半桥功率变换电路............................................224.2.3脉宽调制控制电路...................................................234.2.4多路直流稳压输出电路............................................234.2.5+5VSB、PS-ON、PW-OK控制信号.............................244.2.6自动稳压与保护控制电路........................................24第5章微机开关电源电路图的分析..............................................255.1交流输入整流滤波电路.....................................................255.2辅助电源电路.....................................................................265.3PS-ON信号控制电路..........................................................275.4PW-OK信号控制电路..........................................................285.5脉宽调制控制电路.............................................................295.6功率变换及直流输出电路.................................................305.7自动稳压控制电路.............................................................31结论...................................................................................