多路输出反激式开关电源设计摘要:以UC3844芯片为控制核心，设计并制作了多路输出反激式开关电源。完成了多路输出反激式开关电源系统设计，完成具体模块电路详细设计，包括EMI滤波电路、前级保护和整流桥电路、缓冲吸收电路、高频变压器、UC3844的启动与驱动电路、电流检测和过流保护电路等。合理选择、设计和分配了开关电源各电路参数；设计出电路原理图，根据设计规范制作出PCB，并组装出电源样机，最后对设计的样机进行测试验证。开关电源样机输出电压稳定性较高，输出电压纹波较小，符合设计规范小于80mV的要求；样机整体测试结果表明，电源各项指标均符合要求，输出稳定，性能较好。关键词：开关电源；反激式；UC3844；模块化DesignofMulti-outputFlybackSwitchingPowerSupplyAbstract:Itwasdesignedandproducedasetofmultipleoutputfly-backswitchingpowersupply,usingthechipUC3844asthecontrolcore.Thedesignofthesystemandspecificmodulecircuitswascompleted.ThemodulecircuitsincludeEMIfiltercircuit,levelprotectionandbridgerectifiercircuit,snubbercircuit,highfrequencytransformer,startanddrivecircuitofUC3844,currentsensingandover-currentprotectioncircuit.Theparametersofswitchingpowersupplycircuitwerechose,designedanddistributedreasonably.Accordingtotheschematiccircuitdesignanddesignspecifications,weproducedthePCB,andassembledtheprototypeofpowersupply,alsofinishedthetestinthefinal.Thehigherstabilityoftheoutputvoltageoftheswitchingpowersupplyprototype,theoutputvoltagerippleissmall,meetthedesignspecificationstotherequirementsoflessthan80mV;Theprototypeoftheoveralltestresultsshowthatthepoweroftheindicatorsareinlinewiththerequirements,outputstability,betterperformance.Keywords:switchpowersupply；flyback；UC3844；Modular目录1概述..............................................................................................................................11.1课题研究背景与意义...........................................................................................11.2课题设计内容.......................................................................................................12反激式开关电源系统分析..............................................................................................12.1反激变换器工作原理分析...................................................................................12.2控制电路分析.......................................................................................................32.3系统整体架构.......................................................................................................53系统设计..........................................................................................................................53.1变压器设计...........................................................................................................53.2控制芯片选择.....................................................................................................103.3控制芯片驱动电路及定时电阻电容计算.........................................................123.4缓冲吸收电路.....................................................................................................163.5前置保护电路.....................................................................................................173.6EMI滤波电路选择与设计.................................................................................173.7输入整流滤波电路...............................................................................................
