STL4984D基于L4984D连续导通模式PFC预稳压器参考设计方案

STL4984D基于L4984D连续导通模式PFC预稳压器参考设计方案关键词：L4984D,PFC预稳压器ST公司的L4984D是一款线性调制确定关断时间控制电流型PFC控制器，在该控制器工作在连续导通模式时，作为升压PFC转换器具有线性调制确定关断时间控制属性允许工作在确定频率操作模式。该芯片采用10引脚的SO封装，在连续导通模式下，工作在升压PFC预稳压状态时兼容EN61000-3-2和JEIDA-MITI标准。该芯片可提供功率跨度从几百瓦到一千瓦及以上。本文首先介绍芯片的简介、特性、内部框图及应用领域，并给出相应设计方案的设计原理图、元器件列表及PCB元件布局图。TheL4984Disacurrent-modePFCcontrolleroperatingwithline-modulatedfixed-off-time(LM-FOT)control.AproprietaryLM-FOTmodulatorallowsfixed-frequencyoperationforboostPFCconvertersaslongastheyareoperatedinCCM(continuousconductionmode).Thechipcomesina10-pinSOpackageandoffersalow-costsolutionforCCM-operatedboostPFCpre-regulatorsinEN61000-3-2andJEIDA-MITIcompliantapplications,inapowerrangethatspansfromfewhundredWto1KWandabove.Thehighlylinearmultiplierincludesaspecialcircuit,abletoreducethecrossoverdistortionoftheACinputcurrent,thatallowswide-range-mainsoperationwithareasonablylowTHD,evenoveralargeloadrange.Theoutputvoltageiscontrolledbymeansofavoltage-modeerroramplifierandanaccurate(1%atTj=25°C)internalvoltagereference.Loopstabilityisoptimizedbythevoltagefeedforwardfunction(1/V2correction),whichinthisICusesaproprietarytechniquethatalsosignificantlyimproveslinetransientresponseinthecaseofmainsdropsandsurges(“bi-directional”).ThedevicefeatureslowconsumptionandincludesadisablefunctionsuitableforICremoteon/off.Thesefeaturesallowuseinapplicationswhichalsocomplywiththelatestenergysavingrequirements(BlueAngel,ENERGYSTAR®,Energy2000,etc.).Inadditiontoovervoltageprotectionabletokeeptheoutputvoltageundercontrolduringtransientconditions,theICisalsoprovidedwithprotectionagainstfeedbackloopfailuresorerroneoussettings.Otheronboardprotectionfunctionsallowthatbrownoutconditionsandboostinductorsaturationcanbesafelyhandled.Soft-startlimitspeakcurrentandextendsoff-timetopreventfluxrunawayintheinitialcycles.Thetotempoleoutputstage,capableof600mAsourceand800mAsinkcurrent,issuitableforbigMOSFETsorIGBTdrive.L4984D主要特性：•Line-modulatedfixed-off-time(LM-FOT)controlofCCM-operatedPFCpre-regulators•ProprietaryLM-FOTmodulatorfornearlyfixedfrequencyoperation•ProprietarymultiplierdesignforminimumTHDofACinputcurrent•Fast“bi-directional”inputvoltagefeedforward(1/V2correction)•Accurateadjustableoutputovervoltageprotection•Protectionagainstfeedbackloopfailure(latchedshutdown)•Inductorsaturationprotection•ACbrownoutdetection•Digitalleading-edgeblankingoncurrentsense•Soft-start•1%(atTj=25°C)internalreferencevoltage•-600/+800mAtotempolegatedriverwithactivepull-downduringUVLOandvoltageclamp•SSOP10packageL4984D应用：•PFCpre-regulatorsfor:–IEC61000-3-2andJEIDA-MITIcompliantSMPSinexcessof1KW–DesktopPC,server,webserver图1.L4984D内部方框图L4984D方案介绍：ThisapplicationnotedescribesthedemonstrationboardEVL4984-350W,basedonthe“ContinuousConductionMode”PFC(CCM)controller,theL4984D,andpresentstheresultsofitsbenchevaluation.Theboardimplementsa350W,wide-rangeinput,PFCpreconditionersuitableforallSMPSfrom150WtothoseinthekilowattrangewhichmustmeettheIEC61000-3-2ortheJEITA-MITIregulation.KeyFeaturesLinevoltagerange:90to265VacMinimumlinefrequency(fL):47HzRegulatedoutputvoltage:400VRatedoutputpower:350WMaximum2fLoutputvoltageripple:12.5V(peak-to-peak)Hold-uptime:20ms(VDROPafterhold-uptime:300V)Switchingfrequency:70kHzMinimumefficiency:94%(atVin=90Vac,Pout=350W)PCB:single-side,70um,CEM-1,112x114mmL4984D方案原理图：图2.L4984D方案原理图L4984D方案材料清单：AO-Electronics傲壹电子官网：中文网：元件布局图：