电流ncp是什么

www.
onsemi.
cn交错式功率因数校正InterleavedPFC2议程Agenda简介Introduction:交错式PFC基础知识Basicsofinterleaving主要优势MainbenefitsNCP1631:新颖的交错式PFC控制器NCP1631:anovelcontrollerforinterleavedPFC异相管理Out-of-phasemanagementNCP1631支持使用较小电感TheNCP1631allowstheuseofsmallerinductors主要功能Mainfunctions实验结果及性能Experimentalresultsandperformance一般波形Generalwaveforms能效Efficiency总结Summary3以两个功率为(Pin(avg)/2)的较小PFC段替代单个较大PFC段TwosmallPFCstagesdelivering(Pin(avg)/2)inlieuofasinglebigone如果两个相位异相,因此产生的电流(IL(tot))和(ID(tot))纹波大幅减小Ifthetwophasesareout-of-phase,theresultingcurrents(IL(tot))and(ID(tot))exhibitadramaticallyreducedripple.
交错式功率因数校正(PFC)InterleavedPFCEMIFilterAclineLOAD1234586712345867NCP1601NCP1601()inVtoutV()LtotI2LI1LI2DI1DIbulkC()inIt()DtotIEMIFilterAclineLOAD1234586712345867NCP1601NCP1601()inVtoutV()LtotI2LI1LI2DI1DIbulkC()inIt()DtotIEMIFilterAclineLOAD1234586712345867NCP1601NCP1601()inVtoutV()LtotI2LI1LI2DI1DIbulkC()inIt()DtotI4交错式PFC优势InterleavedBenefits所用元器件更多,但Morecomponentsbut:150WPFC比300WPFC更易于设计A150-WPFCiseasiertodesignthana300-Wone模块化途径Modularapproach散热更好Betterheatingdistribution扩展临界导电模式(CrM)范围ExtendedrangeforCriticalConductionMode(CrM)元件尺寸更小,支持纤薄设计Smallercomponents(帮助符合严格的外形因数需求,如平板电视helpmeetstrictformfactorneeds–e.
g.
,flatpanels)两个不连续导电模式(DCM)PFC看上去象一个连续导电模式(CCM)PFC转换器TwoDCMPFCslooklikeaCCMPFCconverter…简化电磁干扰(EMI)滤波,减小输出均方根(rms)电流EasesEMIfilteringandreducestheoutputrmscurrent5输入及输出电流InputandOutputCurrentEMIFilterAclineLOAD1234586712345867NCP1601NCP1601()inVtoutV()LtotI2LI1LI2DI1DIbulkC()inIt()DtotIEMIFilterAclineLOAD1234586712345867NCP1601NCP1601()inVtoutV()LtotI2LI1LI2DI1DIbulkC()inIt()DtotIEMIFilterAclineLOAD1234586712345867NCP1601NCP1601()inVtoutV()LtotI2LI1LI2DI1DIbulkC()inIt()DtotI什么是IL(tot)总输入电流纹波WhatistherippleoftheIL(tot)totalinputcurrent什么是ID(tot)总输出电流纹波WhatistherippleoftheID(tot)totaloutputcurrent6低交流线路时的输入电流纹波InputCurrentRippleatLowLine当输入电压保持低于输出电压的一半时,输入电流看上去象CCM滞后PFC的输入电流WhenVinremainslowerthanVout/2,theinputcurrentlookslikethatofaCCM,hystereticPFC(IL(tot))在两个接近的正弦迹线间摆动(IL(tot))swingsbetweentwonearlysinusoidalenvelopsPeak,averagedandvalleycurrent@90Vrms,320Winput(Vout=390V)012345670.
00%25.
00%50.
00%75.
00%100.
00%timeasapercentageofaperiod(%)Peak,valleyandaveragedInputCurrent(A)峰值电流迹线Envelopforthepeakcurrents谷底电流迹线EnvelopforthevalleycurrentsIin(t)IL(tot)7高交流线路时的输入电流纹波InputCurrentRippleatHighLine输入电压超过输出电压的一半时,谷底电流保持恒定!
WhenVinexceeds(Vout/2),thevalleycurrentisconstant!
此电流等于Itequates其中,Rin是PFC输入阻抗whereRinisthePFCinputimpedancePeak,averagedandvalleycurrent@230Vrms,320Winput(Vout=390V)0.
00.
51.
01.
52.
02.
53.
00.
00%25.
00%50.
00%75.
00%100.
00%timeasapercentageofaperiod(%)Peak,valleyandaveragedInputCurrent(A)Vin=Vout/2时无纹波NoripplewhenVin=Vout/22outinVR()2()22inavgoutoutininrmsPVVRV=Iin(t)IL(tot)8交流线路输入电流LineInputCurrent对于每个支路而言,正弦波的某处波形有如:Foreachbranch,somewherewithinthesinusoid:两个平均正弦相位电流之和得到总线电流:Thesumofthetwoaveraged,sinusoidalphasescurrentsgivesthetotallinecurrent:假定有极佳的电流平衡:Assumingaperfectcurrentbalacing:每个支路的峰值电流就是Iin(t):ThepeakcurrentineachbranchisIin(t)()122swswswinLLTLtotTTIIII==+1222swswLLinTTIII==IL11swLTI12swLTIIL11swLTI12swLTI9充电电流的交流分量AcComponentoftheRefuelingCurrent充电电流(输出二极管电流)取决于工作模式Therefuelingcurrent(outputdiode(s)current)dependsonthemode:Phase1Phase2单相CCMSinglephaseCCM单相CrMSinglephaseCrM交错式CrMInterleavedCrM23ininoutVIV23ininoutVIVrmsvalueoverTswrmsvalueoverTswrmsvalueoverTswininoutVIV2inIinIinIinI10大电容均方根电流降低AReducedRmsCurrentintheBulkCapacitor正弦电流积分可得到(电阻型负载):Integrationoverthesinusoidleadsto(resistiveload):交错式PFC大幅降低均方根电流Interleavingdramaticallyreducesthermscurrents降低损耗,减少发热量,提升可靠性reducedlosses,lowerheating,increasedreliability*频率钳位CrMFrequencyClampedCrM二极管均方根电流Diode(s)rmscurrent(ID(rms))ID(tot)(rms)=1.
5AIC(rms)=1.
3AID(rms)=2.
2AIC(rms)=2.
1AID(rms)=1.
9AIC(rms)=1.
7A300-W,Vout=390VVin(rms)=90VCapacitorrmscurrent(IC(rms))交错式CrM或FCCrM*PFCInterleavedCrMorFCCrM*PFC单相CrM或FCCrM*PFCSinglephaseCrMorFCCrM*PFC单相CCMPFCSinglephaseCCMPFC22()3229outoutinrmsoutoutPPVVVηπ22()1629outoutinrmsoutoutPPVVVηπ22()823outoutinrmsoutoutPPVVVηπ2()82233outinrmsoutPVVηπ2()82233outinrmsoutPVVηπ2()823outinrmsoutPVVηπ11交错式PFC小结Finally…交错式PFC结合了InterleavedPFCcombines:临界导电模式(CrM)工作的优势TheadvantagesofCrMoperations不需要低反向恢复时间(trr)二极管Noneedforlowtrrdiode高能效Highefficiency降低输入电流纹波,将大电容中均方根电流减至最小Areducedinputcurrentrippleandaminimizedrmscurrentinthebulkcapacitor散热更好Abetterdistributionofheating元器件数量更多,但尺寸"较小"Morecomponentsbut"small"ones精心调配,适合纤薄外形因数应用,如笔记本适配器和液晶电视WelladaptedtoslimformfactorapplicationssuchasnotebookadaptersandLCDTVs更多信息参见安森美半导体应用笔记AND8355RefertoapplicationnoteAND8355formoredetails12议程Agenda简介Introduction:交错式PFC基础知识Basicsofinterleaving主要优势MainbenefitsNCP1631:新颖的交错式PFC控制器NCP1631:anovelcontrollerforinterleavedPFC异相管理Out-of-phasemanagementNCP1631支持使用较小电感TheNCP1631allowstheuseofsmallerinductors主要功能Mainfunctions实验结果及性能Experimentalresultsandperformance一般波形Generalwaveforms能效Efficiency总结Summary13NCP1631概览NCP1631Overview交错式2相PFC控制器Interleaved,2-phasePFCcontroller频率钳位临界导电模式(FCCrM)优化完整负载范围内的能效FrequencyClampedCriticalconductionMode(FCCrM)tooptimizetheefficiencyovertheloadrange.
包括启动、过流保护(OCP)或瞬态序列在内的所有条件下提供稳固的异相工作Substantialout-of-phaseoperationinallconditionsincludingstart-up,OCPortransientsequences.
具备前馈,改善环路补偿Feedforwardforimprovedloopcompensation简化下行转换器设计Easeddesignofthedownstreamconverter:提供"pfcOK"信号,含动态响应增强器及待机管理功能pfcOK,dynamicresponseenhancer,standbymanagement高保护等级Highprotectionlevel:输入欠压保护,精确的1引脚限流,浪涌电流检测,单独引脚用于(可编程)过压保护(OVP)等Brown-outprotection,accurate1-pincurrentlimitation,in-rushcurrentsdetection,separatepinfor(programmable)OVP…14NCP1631概览NCP1631Overview交错式2相PFC控制器Interleaved,2-phasePFCcontroller零电压检测(第2支路)Zerovoltagedetection(branch1)固定最大导通时间Fixesthemax.
on-time前馈Feed-forward一个CS引脚感测总输入电流,用于过流保护及浪涌检测OneCSpintosensethetotalinputcurrentforOver-CurrentProtectionandInrushdetection闩锁输入:若闩锁电压高于2.
5V,控制器关闭Latchinput:ifVLatch>2.
5V,thecontrollershutdowns固定最大开关频率Fixesthemax.
switchingfrequency调节稳压环路带宽Adjuststheregulationloopbandwidth调节频率反走特性AdjuststheFrequencyFoldbackcharacteristic输入欠压检测,带50ms沿隐延迟,符合维持时间要求Brown-outdetectionwitha50-msblankingdelaytomeethold-uptimerequirements过压及欠压保护(OVP,UVP)OverandUndervoltageprotection(OVP,UVP)PFC就绪时(稳态)高电平(5V)High(5V)whenPFCisready(steadystate)零电压检测(第2支路)Zerovoltagedetection(branch2)15NCP1631典型应用NCP1631TypicalApplication完全内部实现相位同步SynchronizationofphasesiscompletelyinternalEMIFilterAclineVinLOADDRVoutCinCI12341316141556789121011VccpfcOKRocpRzcd1Rzcd22bulkL2L1M1M2D1coil2Icoil1IinCoscCpRzCzRtRFFRout2Rout1VoutRbo1Rbo2Cbo2OVPinOVPinsenseVaux2Vaux2FBRout3BO单个电流感测电阻1currentsenseresistor提示下行转换器PFC已经就绪IndicatesthedownstreamconverterthatthePFCisready16交错式PFC:主/从方案Interleaving:Master/SlaveApproach…主支路自由工作Themasterbranchoperatesfreely从支路以180°相移跟随主支路工作Theslavefollowswitha180°phaseshift主要挑战:维持CrM工作(无CCM,无死区时间)Mainchallenge:maintainingtheCrMoperation(noCCM,nodead-time)2swT2swT2swT2swT2swT2swT电流模式:电感不平衡Currentmode:inductorunbalance电压模式:导通时间转换Voltagemode:on-timeshift2swT2swT2swT2swT2swT2swTL2L2(1)2(2)1ininILIL=20人为制造不平衡ArtificialUnbalancing在测试中,采用300H的线圈来替代支路1中的150H电感Inthistest,the150-Hinductorofbranch1isreplacedbya300-Hcoil!
!
!
!
因此,支路2消耗更多电流,且支路2中的MOSFET(通常)更热Hence,morecurrentisdrawnbybranch2andMOSFETofbranch2is(normally)hotter后面的图中显示PFC段在这些极端条件及满载下的工作特性ThefollowingplotsshowhowthePFCstagebehavesintheseextremeconditionsandfullload21在恶劣状态下仍然工作StillOperatesinaRobustManner…120Vrms,0.
8A(PF=0.
997,THD=6%)230Vrms,0.
8A(PF=0.
980,THD=11%)Iline(5A/div)Iin(2A/div)Iline(5A/div)放大ZoomDRV2(10V/div)DRV2(10V/div)DRV2(10V/div)DRV2(10V/div)Iin(5A/div)Iin(2A/div)Iin(5A/div)DRV2DRV2DRV2DRV2OSCpinvoltage(5V/div)OSCpinvoltage(5V/div)22CrM开关频率变化SwitchingFrequencyVariationsinCrMNormalizedfswvariationswithintheaclinesinusoid(Vin,rms=90V,Vout=400V)0.
000.
501.
001.
500.
001.
002.
003.
00ωtNormalizedfsw(atthesinusoidtop)vsVin,rms0.
501.
001.
502.
002.
5080110140170200230260Vin,rms(V)fsw/fsw(90)开关频率随着输入功率、交流线路幅度的不同而以正弦波变化Theswitchingfrequencyvariesversustheinputpower,theaclineamplitudeandwithinthesinusoidfsw在轻载时变高,导致较大开关损耗fswbecomeshighatlightload,leadingtolargeswitchinglosses应当限制fswfswshouldbelimitedfsw(normalized)vsPin05101520050100150200Pin(W)fsw/fsw(200W)开关频率变大fswbecomeslargeVin(t)23限制开关频率以优化能效LimitingfswtoOptimizetheEfficiency在正弦波顶部Atthetopofthesinusoid:CrM工作要求大电感来限制轻载时的开关损耗CrMoperationrequireslargeinductorstolimittheswitchinglossesatlightload我们是否能够不使用大尺寸电感而钳位开关频率Can'tweclampfswnottoover-dimensionL频率钳位临界导电模式FrequencyClampedCriticalconductionMode(FCCrM)(),,,214inpkinpkswinavgoutVVfLPV=24频率钳位临界导电模式(FCCrM)FrequencyClampedCriticalConductionMode轻载时,电流周期短Atlightload,thecurrentcycleisshort电流周期短于振荡器周期时,振荡器周期过去后才有新的电流周期死区时间(DCM)Whenshorterthantheoscillatorperiod,nonewcycleuntiltheoscillatorperiodiselapseddead-times(DCM)增加导通时间以补偿死区时间功率因数(PF)没有降低(安森美半导体专有技术)On-timesareincreasedtocompensatethedead-timesnoPFdegradation(ONproprietary)25NCP1631工作-频率钳位临界导电模式(FCCrM)NCP1631Operation-FCCrM在FCCrM,开关频率钳位InFCCrM,theswitchingfrequencyisclamped:轻载时及接近线路过零点时频率固定Fixedfrequencyinlightloadmodeandnearthelinezerocrossing满载时实现临界导电模式(CrM)Criticalconductionmode(CrM)achievedatfullload.
FCCrM优化完整负载范围内的能效FCCrMoptimizestheefficiencyovertheloadrange.
FCCrM缩小要电磁干扰(EMI)滤波的频率范围FCCrMreducestherangeoffrequenciestobefiltered(EMI)FCCrM支持使用小尺寸电感FCCrMallowstheuseofsmallerinductors不需大电感以限制频率范围!
Noneedforlargeinductancestolimitthefrequencyrange!
如150H电感(PQ2620)适合宽主电源范围的300W应用E.
g.
,150H(PQ2620)forawidemains300-Wapplication频率反走功率降低轻载时的钳位频率,进一步改善能效FrequencyFoldbackreducestheclampfrequencyatlightloadtofurtherimprovetheefficiency26NCP1631频率反走NCP1631FrequencyFoldback输入功率减小到低于预设功率电平(PLL)时,钳位频率线性降低TheclampfrequencylinearlydecayswhenPingoesbelowapresetlevel(PLL)PLL由引脚6电阻设定PLLisprogrammedbythepin6resistor()()μ=661051.
6615810inpinpinFFinHLPRARP引脚6的输出电压正比于功率.
IFF电流钳位至105A,用于给振荡器电容充电及放电Pin6pinsoutavoltageproportionaltothepower.
TheIFFcurrentisclampedto105Aandusedtochargeanddischargetheoscillatorcapacitor钳位频率逐渐减小Gradualdecayoftheclampfrequency工作不间断Nodiscontinuityintheoperation振荡器电容两端的电阻设定最低钳位频率(如20kHz,参见应用笔记AND8407)Aresistoracrosstheoscillatorcapacitorsetsaminimumclampfrequency(e.
g.
,20kHz-seeapplicationnoteAND8407)Load(%)示例:40%负载及130kHz额定频率时的频率反走Example:FFat40%loadanda130-kHznominalfrequency020406080100120140160020406080100Fsw(max)nomFsw(max)IFF105A(Pin)HL是PFC段能提供的最大功率(Pin)HListhemax.
powerdeliverablebythePFCstage27轻载工作LightLoadOperationFullload,90V重负载条件下的CrM工作CrMatheavyloadconditions死区时间Dead-time输入电流Inputcurrent(2A/div)Vaux1(10V/div)Vaux2(10V/div)25%负载load,90V轻载时频率减小Frequencyisreducedatlightload采用深度DCM工作,减小开关损耗HeavyDCMoperationtoreducetheswitchinglosses28空载能耗NoLoadConsumption数据系在300WNCP1631演示板在测得Measuredonthe300-WNCP1631demoboard外部VCC、3颗680kΩ电阻给X2电容放电ExternalVcc,3*680-kΩresistorstodischargetheX2capacitors频率反走技术不仅提升轻载能效,还提升空载条件下的能效FrequencyFoldbackimprovestheefficiencyinlightloadbutalsoinno-loadconditions230115230115230115交流线路电压LineVoltage(V)8238FrequencyFoldback(RFF=4.
7kΩ)oneVoutsensingnetworkforFBandOVPforatotal48-AleakageontheVoutrail13496FrequencyFoldback(RFF=4.
7kΩ)2separateVoutsensingnetworksforFBandOVPforatotal185-AleakageontheVoutrail(*)138107NoFrequencyFoldback(pin6grounded)2separateVoutsensingnetworksforFBandOVPforatotal185-AleakageontheVoutrail输入能耗InputPower(mW)条件Conditions(*)默认演示板配置Defaultdemoboardconfiguration29NCP1631故障管理NCP1631FaultManagement输入欠压Brown-out欠压保护Undervoltageprotection闩锁条件Latch-offcondition晶圆过热DieovertemperatureRt引脚提供的电流太小ToolowcurrentsourcedbytheRtpin提升Vcc工作电平ImproperVcclevelforoperation在关闭模式,电路主要元件休眠,能耗极低:210μA,theOCPswitchclosesandacurrentequalto0.
5*(ICS–210μA)isinjectedintothenegativeinputoftheVTONprocessingopamp导通时间以与过流幅度成比例地急剧缩短theon-timesharplyreducesproportionallytothemagnitudeoftheover-currentevent.
工作无间断,仍维持异相工作Nodiscontinuityintheoperation,out-of-phaseoperationismaintained在额定瞬态条件期间不需要防止OCP动作NoneedforpreventingOCPfromtrippingduringanormaltransient能够精确限制电流ThecurrentcanbeaccuratelylimitedIline(2A/div)Iin(2A/div)Vcontrol(1V/div)Iline(2A/div)Iin(2A/div)Vcontrol(1V/div)32NCP1631浪涌电流检测NCP1631In-rushCurrentDetection信号处于高电平时(ICS>14μA)(IILIMIT的7%)关闭输出驱动Disablesoutputdrivewhensignalishigh(ICS>14μA)(7%ofIILIMIT)一旦电路开始工作,电路将把浪涌保护接地CircuitrytogroundtheIn-rushprotectiononcethecircuitbeginsoperation大电容插入主电源电路时,突然充电至电源线路电压,充电电流(浪涌电流)极大.
这时候驱动导通可能会损坏MOSFET.
Whenpluggedintothemains,thebulkcapacitorisabruptlychargedtothelinevoltageandthechargecurrent(in-rushcurrent)ishuge.
Driveturn-onduringthistimecandamagetheMOSFETs.
33NCP1631过压保护NCP1631OverVoltageProtection反馈(FB)及过压保护(OVP)各有单独引脚(提供冗余)SeparatepinsforFBandOVP(redundancy)这两种功能使用相同的2.
5V内部参考,用于简易、精确地设定OVP电平Thetwofunctionssharethesame2.
5-VinternalreferenceforaneasedandaccuratesettingoftheOVPlevel()3()2V1outovpoutoutnomoutRVR=+方法1:OVP和FB共用一个反馈网络Method1:Onefeed-backnetworkforOVPandFB方法2:OVP和FB用两个独立的反馈网络Method2:Twoseparatefeed-backnetworks()122()122VoutovpovpovpoutoutnomoutoutovpRRRVRRR+=+3450ms消隐时间的输入欠压(BO)保护Brown-outProtectionwitha50-msBlankingTime忽略时间短于50ms的主电源中断Mainsinterruptionsshorterthan50msareignored消隐时间帮助满足维持时间要求Theblankingtimehelpsmeethold-uptimerequirementsBO引脚电压用于前馈TheBOpinvoltageservesforfeedforward交流线路电流Aclinecurrent(2A/div)Vbulk(100V/div)Vin(100V/div)BO引脚电压BOpinvoltage(1V/div)对于消隐时间而言,BO引脚电压维持在BO阈值附近,当交流线路恢复时不延迟电路重启Fortheblankingtime,theBOpinvoltageismaintainedaroundtheBOthresholdnottodelaythecircuitrestartwhenthelinehasrecovered20ms时间的线路中断20-mslineinterruption35NCP1631pfcOK/REF5V信号NCP1631pfcOK/REF5VSignalpfcOK信号能用于启用/关闭下行转换器ThepfcOKsignalcanbeusedtoenable/disablethedownstreamconverter.
PFC段正常工作时pfcOK信号是高电平(5V),否则是低电平Itishigh(5V)whenthePFCstageisinnormaloperationandlowotherwise.
pfcOK信号为低电平的条件ThepfcOKsignalislow:任何时候PFC因检测到重要故障而关闭时(欠压锁定条件、热关闭、欠压保护、输入欠压、闩锁/关闭、Rt引脚开路)AnytimethePFCisoffbecauseamajorfaultisdetected(UVLOcondition,thermalshutdown,UVP,Brown-out,Latch-off/shutdown,Rtpinopen)PFC段获得额定大电压前的启动相位期间Forthestart-upphaseofthePFCstageuntilthenominalbulkvoltageisobtainedpfcOK引脚能用作5V电源(电流能力5mA)ThepfcOKpincanbeusedasa5-Vpowersource(5-mAcapability)36使用简单易用的Excel电子表格来计算外部元件(www.
onsemi.
cn)A(simplebuteasytouse)ExcelSpreadsheet(www.
onsemi.
com)computestheexternalcomponents37议程Agenda简介Introduction:交错式PFC基础知识Basicsofinterleaving主要优势MainbenefitsNCP1631:新颖的交错式PFC控制器NCP1631:anovelcontrollerforinterleavedPFC异相管理Out-of-phasemanagementNCP1631支持使用较小电感TheNCP1631allowstheuseofsmallerinductors主要功能Mainfunctions实验结果及性能Experimentalresultsandperformance一般波形Generalwaveforms能效Efficiency总结Summary38NCP1631演示板NCP1631Demoboard宽电压范围、300WPFC预转换器Widemains,300W,PFCpre-converterNCP1631MUR55039+-INU1KBU6KC5100nFC61FType=X2CM185-265VrmsLNEarthC104.
7nFType=Y1C164.
7nFType=Y1C18680nFL4150HD5MUR550R2450m(3W)VinR18560kC2100F/450VX7VccR2527kR1522kX6IPP50R250D4MUR550pfcOKX1X4IPP50R250R11.
8kR1422kIinC251FR3633kR3318kR4027kR46120kR374.
7k+-15V+-390VR411800kR421800kR431800kR441800kC221nFR381800kR23820kR391800kR321800kR311800kC271nFR2010kD151N4148Q22N2907R172.
2R1110kD141N4148Q12N2907R72.
2DRV2DRV2C32100F/25VC33100nFC30100nFD2115VR21kC3410nFD161N5406VoutD171N5406C20150nFC15220pFC28220nFR34270kR121680kR122680kR123680kR160Vaux1DRV1Vaux2R21012345867910111213141516U2S4S5D18NCD20NCDRV1Vaux2C21NCC29NCVaux1R61kD3LEDD61N4148D2NCC31NCD19NCR47NCVaux1OVPinOVPinC7NCR12NCD22NCDRV1D23NCDRV2NCP1631演示板电路图NCP1631DemoboardSchematic300W、宽电压范围PFC预转换器300W,widemainsPFCpre-converter如果Vcc超过17.
5V,电路闩锁关闭.
能用作热保护ThecircuitislatchedoffifVccexceeds17.
5V.
Couldbeusedforthermalprotection40输入电压及电流InputVoltageandCurrent正如预料,输入电流看上去象是CCM波形Asexpected,theinputcurrentlookslikeaCCMone高交流线路时,频率反走影响纹波Athighline,frequencyfoldbackinfluencestheripple满载Fullload,120VrmsIline(5A/div)Vin(100V/div)IL(tot)(5A/div)Iline(5A/div)Vin(200V/div)IL(tot)(2A/div)满载Fullload,230Vrms41波形图放大ZoomofthePrecedentPlots这些图在正弦波形顶部获得Theseplotswereobtainedatthesinusoidtop电流以每个相位频率的2倍摆动Thecurrentswingsattwicethefrequencyofeachphase低及高交流线路时相移充分达到180°Atlowandhighline,thephaseshiftissubstantially180°满载Fullload,90Vrms满载Fullload,230VrmsIL(tot)(2A/div)DRV1IL(tot)(1A/div)DRV2DRV1DRV242充电序列RefuelingSequencesCrM的低交流线路电压时谷底开关CrMatlowlinewithvalleyswitching高交流线路电压时固定频率工作(频率钳位)Fixedfrequencyoperationathighline(frequencyclamp)两种情况下都异相工作Out-of-phaseoperationinbothcases满载Fullload,90Vrms满载Fullload,230VrmsIL(tot)(2A/div)IL(tot)(1A/div)VZCD1VZCD2VZCD1VZCD243能效测量EfficiencyMeasurements输出电压通常为390VTheoutputvoltageisgenerally390V对于300W应用而言,输出电流是:Fora300-Wapplication,theoutputcurrentis:满载时770mA770mAatfullload20%负载时154mA154mAat20%oftheload两类电流一般以相同工具测量Bothcurrentsaregenerallymeasuredwiththesametool处于20%负载时,输入功率为63WIf@20%oftheload,theinputpoweris63W输出电流1mA误差会造成:1-mAerrorinIoutleadstoIout=153mA能效Eff=100x390x0.
153/63=94.
7%Iout=155mA能效Eff=100x390x0.
155/63=95.
9%1mA误差导通1.
2%的能效差别!
A1-mAerrorcausesa1.
2%differenceintheefficiency!
在10%及20%负载条件下测量时需要细心!
Measurements@10%and20%oftheloadneedcare!
!
!
44能效测量EfficiencyMeasurements能效并不只取决于控制模式Theefficiencydoesnotonlydependonthecontrolmode电感、MOSFET、二极管、EMI滤波器等都会影响能效Theinductor,theMOSFETs,diodes,EMIfilter…playarole例如,我们可以比较采用200HPQ2625电感与采用150HPQ2620电感时的能效差别Forinstance,ifwecomparetheefficiencywitha200-HPQ2625inductortothatwitha150-HPQ2620one:Efficiency@230V96.
496.
696.
897.
097.
297.
497.
697.
898.
098.
2020406080100120Load(%)Efficiency(%)200H150H频率反走限制轻载时的能效差别FrequencyFoldbacklimitsthedifferenceatlightload45演示板能效DemoboardEfficiency在20%至100%负载范围,能效保持为Inthe20%to100%range,theefficiencyremains:低线路电压时高于95.
8%>95.
8%atlowline高线路电压时高于97.
0%>97.
0%athighline更多信息请访问www.
onsemi.
cn,参见NCP1631EVB/D资料RefertoNCP1631EVB/Datwww.
onsemi.
comfordetails92.
0093.
0094.
0095.
0096.
0097.
0098.
0099.
00020406080100120Load(%)Efficiency(%)115V230V46调节频率反走TweakingFrequencyFoldback…能在pfcOK(5V)及频率反走引脚间增加电阻AresistorcanbeaddedbetweenthepfcOK(5V)andfrequencyfoldbackpinsVREGUL正比于PFC功率(VREGULisproportionaltothePFCpower)可编程最小频率Programmableminimumfrequency可编程额定频率Programmablenominalfrequencyfsw(max)VREGUL()()21125105RVRARR++2125REGULRVVRR=+fsw(max)VREGUL()()21125105RVRARR++2125REGULRVVRR=+增加电阻R1R1addition这样做,频率钳位会大幅减弱Doingso,thefrequencyclampdecaysmoresharply:21R1R2pfcOK/5VFFpinfsw(max)VREGUL2105RAfsw(max)VREGUL2105RA47能效提升EfficiencyImprovement振荡器引脚上的电阻能设定最低频率Aresistorontheoscillatorpinsetstheminimumfrequency增加电阻R1时,PFC段在10%和20%负载条件下工作在最低频率(20kHz)WithR1,thePFCstageoperatesattheminimumfrequency(20kHz)at10%and20%oftheload调节频率反走进一步提升轻载能效Thetweakfurtherimprovesthelightloadefficiency92.
0093.
0094.
0095.
0096.
0097.
0098.
0099.
000102030405060708090100Load(%)Efficiency(%)115V230V92.
0093.
0094.
0095.
0096.
0097.
0098.
0099.
000102030405060708090100Load(%)Efficiency(%)115V230V95%95%增加R1R1addition1%1%48议程Agenda简单Introduction:交错式PFC基础知识Basicsofinterleaving主要优势MainbenefitsNCP1631:新颖的交错式PFC控制器NCP1631:anovelcontrollerforinterleavedPFC异相管理Out-of-phasemanagementNCP1631支持使用较小电感TheNCP1631allowstheuseofsmallerinductors主要功能Mainfunctions实验结果及性能Experimentalresultsandperformance一般波形Generalwaveforms能效Efficiency总结Summary49总结Summary交错式PFC支持使用较小的元器件、改善热性能、增强CrM功率范围并减小电流纹波InterleavedPFCallowsuseofsmallercomponents,improvesthermalperformance,increasestheCrMpowerrangeandreducescurrentripple.
NCP1631以单颗IC方案集成构建强固及紧凑的2相交错式PFC段所需的全部特性,且外部元件极少TheNCP1631providesasingleICsolutionwhichincorporatesallthefeaturesnecessaryforbuildingarobustandcompact2-phaseinterleavedPFCstagewithminimalexternalcomponents.
FCCrM及频率反走支持使用小电感在完整负载范围内的高能效工作ItsFCCrMandfrequencyfoldbackallowsanefficientoperationovertheloadrangewithsmallinductors50ForMoreInformationViewtheextensiveportfolioofpowermanagementproductsfromONSemiconductoratwww.
onsemi.
comViewreferencedesigns,designnotes,andothermaterialsupportingthedesignofhighlyefficientpowersuppliesatwww.
onsemi.
com/powersupplies