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I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IIDESIGNOFAMICRO-COMPUTERSWITCHINGPOWERSUPPLYBASEDONTL494ABSTRACTWiththedevelopmentofswitchingpowersupplyinthefieldofcomputer,correspond,aviationandastronautics,instrumentappearanceandelectricalproductionetc,thedemandoftheproductionareincreasingaspeopleneed,andpeoplehavebroughtforwardhigherrequesttoaspectsuchasthepowerefficiency,bulkfactor,andreliability.Theswitchpowernotonlyvolumeissmallbutalsoefficiencyisheight,weightmakeslight,whicharesubstitutingtheinefficient,bothstupidandseriouslinearitypowerinmanyaspectsstepbystep.Withtheelectricpowerelectronictechnologydevelopment,especiallyhighefficiencydeviceofIGBTandtheMOSFETrapiddevelopment,theswitchingpower’sperformancedevelopvariousanditscostisbecomingcheaperandcheaper,peoplecouldacceptthenewswitchingpower.Theinformationtechnologydevelopmentalsosetahigherrequesttothepowersourcetechnology,thuspromotedtheswitchingpowertechnologydevelopment.Themicrocomputerpowerusuallyadoptspulsewidthmodulationswitchingpowersupply.ThissubjectintroducesakindofPWMtechnologybasedonhalfbridgetypemicrocomputerswitchingpowersupply.ItisthroughtheuseofdriveICTL494controlofthepulseofPWMswitchconductiontocontroldcoutput.InthispaperthemicrocomputerswitchingIIIpowersupplyfiltercircuits,auxiliarypower,PWMcontrolanddrivecircuit,multi-channelDCvoltageoutputcircuit,automaticcontrolcircuitofdetaileddesignmethodanddesignideas,anddetailedcircuit.KEYWORDS:IGBT，PWM，switchingpower,drivecircuit，rectifyIV目录前言....................................................................................1第1章开关电源的发展......................................................31.1开关电源概述...........................................................31.1.1开关电源的工作原理.......................................31.1.2开关电源的组成..............................................41.1.3开关电源的特点..............................................51.2开关电源的分类.......................................................61.3开关器件的分析.......................................................71.3.1开关器件的特征..............................................71.3.2电力二极管......................................................71.3.3电力场效应晶体管MOSFET..............................8第2章主要开关变换电路.................................................102.1推挽开关变换电路.................................................102.2半桥开关变换电路.................................................112.2.1半桥开关变换电路工作原理.........................112.2.2半桥变换器的应用........................................13第3章TL494在微机开关电源中的应用.........................153.1TL494概述..............................................................153.1.1TL494主要特性............................................153.1.2TL494工作原理简述.....................................153.1.3TL494内部电路结构.....................................163.2TL494的各脚功能及参数......................................173.3TL494脉冲控制波形图..........................................193.4TL494构成的PWM控制器电路..............................20第4章微机开关电源的原理与组成.................................234.1微机开关电源的原理.............................................234.2微机开关电源的组成.............................................254.2.1交流输入整流滤波电路.................................25V4.2.2脉冲半桥功率变换电路.................................264.2.3脉宽调制控制电路........................................284.2.4多路直流稳压输出电路.................................284.2.5+5VSB、PS-ON、PW-OK控制信号..................294.2.6自动稳压与保护控制电路.............................29第5章微机开关电源电路图的分析.................................315.1交流输入整流滤波电路..........................................315.2辅助电源电路.........................................................325.3PS-ON信号控制电路..............................................335.4PW-OK信号控制电路..............................................345.5脉宽调制控制电路.................................................355.6功率变换及直流输出电路......................................365.7自动稳压控制电路.................................................38结论..................................................................................40参考文献..............................................................................41致谢..................................................................................42附录..................................................................................43外文资料译文......................................................................481前言电子设备都离不开可靠的电源，进入80年代计算机电源全面实现了开关电源化，率先完成计算机的电源换代，进入90年代开关电源相继进入各种电子、电器设备领域，程控交换机、通讯、电子检测设备电源、控制设备电源等都已广泛地使用了开关电源，更促进了开关电源技术的迅速发展。1994年我国原邮电部作出重大决策，要求通信领域推广使用开关电源以取代相控电源。开关电源的使用为国家节省了大量铜材、钢材和占地面积。目前，