本科毕业论文（20届）多路输出隔离式开关电源设计所在学院专业班级自动化学生姓名学号指导教师职称完成日期年月摘要摘要开关电源是在电子、通信、电气、能源、航天航空、军事以及家电等领域应用非常广泛的一种电力电子装置。它具有电能转换效率高、体积小、重量轻、控制精度高和快速性好等优点，在小功率范围内基本取代了线性调整电源，并迅速向中大功率范围推进，在很大程度上取代了晶闸管相控整流电源。可以说，开关电源技术是目前中小功率直流电能变换装置的主流技术。UC3842是美国Unitrode公司生产的一种高性能单端输出式电流控制型脉宽调制器芯片，可直接驱动双极型晶体管、M0SFEF和IGBT等功率型半导体器件,具有管脚数量少、外围电路简单、安装调试简便、性能优良等诸多优点，广泛应用于计算机、显示器等系统电路中作开关电源驱动器件。UC3842能够通过高频变压器与电网隔离，适合构成小功率开关电源。UC3842构成电路所需的元件极少，非常符合“适用、够用、好用”的原则。本论文主要有以下内容：1）介绍开关电源的产生及发展，开关电源的组成及常用的几种控制方法。介绍了UC3842芯片的构成、特点和工作原理及反激式开关电源的工作原理。2）设计了反激式开关电源高频变压器，包括变压器磁芯的选择及占空比、电感值的计算和各路输出绕组匝数的确定以及气隙的计算。3）设计了基于UC3842芯片的反激式开关电源。包括主电路、反馈电路及各种保护电路。关键字：开关电源，UC3842芯片，反激式变换器AbstractTheswitchingpowersupplyisverywidelyusedinthefieldofelectronics,communications,electrical,energy,aerospace,militaryandhomeappliancesandotherpowerelectronicdevices.Ithasahighpowerconversionefficiency,smallsize,lightweight,highcontrolprecisionandrapidity,etc.,sothatitislargelyreplacedintherangeoflow-powerlinearregulatorpowersupply,andquicklyadvancingtothehighpowerrange,inlargereplacethethyristorphase-controlledrectifierpowersupply.ItcanbesaidthattheswitchingpowersupplytechnologyisthemainstreamtechnologyforsmallandmediumpowerDCconversiondevice.UC3842isahigh-performancesingle-endedoutputcurrentoftheU.S.theUnitrodecompanyproductioncontrolpulsewidthmodulatorchipcandirectlydrivethebipolartransistor,MOSFEFandIGBTpowersemiconductordevices,withasmallnumberofpins,theexternalcircuitissimple,installationissimple,excellentperformanceandmanyotheradvantages,widelyusedincomputers,monitorsandothersystemcircuitforswitchingpower-drivendevices.UC3842throughthehigh-frequencytransformerisolatedfromthegrid,suitabletoconstituteasmallswitchingpowersupply.UC3842constituteacircuitrequiresveryfewcomponents,isconsistentwithapplicableenough,easytouse"principle.Thisthesisismainlythefollowing:Tointroducetheemergenceanddevelopmentoftheswitchingpowersupply,switchingpowersupplycomposedofseveralcommonlyusedcontrolmethods.Flybackswitchingpowersupplywor