其中高压钠灯的电子驱动部分需要把市电从交流转化为直流，LED驱动电源控制精度高，然后参考示例来选择降压电容器的容量。因为通过降压电容C1向负载提供的电流Io,实际上是流过C1的充放电电流Ic.C1容量越大，在各并联支路点均设立独立恒流源，
Diode公司的ZXLD1370是60V高精度降压/升压/升降压LED驱动控制器,输出电流精度0.5%,工作电压6V-60V,DC调光比20:1,500Hz的调光比达1000:1,工作频率高达1MHz,可驱动超过15个串联的led.本文介绍了ZXLD1370主要特性,降压配置框图,升压/升降压配置框图,OVP保护电路,和2.8A降压LED驱动电路图,400mA升压LED驱动电路图,700mA升-降压LED驱动电路图以及相应电路的材料清单与降压和升降压配置电路PCB布局图.
ZXLD1370:60VHIGHACCURACYBUCK/BOOST/BUCK-BOOSTLEDDRIVERCONTROLLER
TheZXLD1370isanLEDdr***ultitopologycontrollerena***ti-topologyenablesittooperateinbuck,boostandbuck-boostconfigurations.
The60Vcapabilitycoupledwithitsmulti-topologycapabilityenablesittobeusedinawiderangeofapplicationsanddriveinexcessof15LEDsinseries.
TheZXLD1370isamodifiedhystereticcontrollerusingapatentpendingcontrolsch***curacydimmingisachievedthroughDCcontrolandhighfrequencyPWMcontrol.
***utputhighlightsafault,whilethemulti-levELstatuspingivesfurtherinformationontheexactfault.
ZXLD1370主要特性:
?0.5%typicaloutputcurrentaccuracy
?6to60Voperatingvoltagerange
?LEDdriversupportsBuck,BoostandBuck-boostconfigurations
?Widedynamicrangedimming
o20:1DCdimming
o1000:1dimmingrangeat500Hz
?Upto1MHzswitching
?HightemperaturecontrolofLEDcurrentusingTADJ
图***1370降压配置框图
图***1370升压/升降压配置框图
图***1370采用热敏电阻和Tadj降压-升压配置框图
图***1370OVP保护电路
图***1370降压和升降压配置电路布局图
图***13702.8A降压LED驱动电路图
2.8A降压LED驱动电路材料清单:
图***1370400mA升压LED驱动电路图
400mA升压LED驱动电路材料清单:
图***1370700mA升-降压LED驱动电路图
700mA升-降压LED驱动电路材料清单
详情请见:
***/***
Renesas公司的R2A20134SP是LED照明的控制IC,具有两种工作模式:临界导通模式(CRM)和固定开关频率模式.CRM模式能精确地控制LED电流和修正功率因素,具有高效率,而固定开关频率模式能大大地降低外接元件数量.本文介绍了两种工作模式连接框图,R2A20134SP多种评估板主要特性,以及R2A20134EVB-NN1E评估板特性,电路图,元件数值计算方法,110VAC和220VAC的材料清单和PCB元件布局图.
***wooperationmodes,CriticalConductionmode(CRM)***nchooseonesuitablemodefortheirpurpose.
AtCriticalConductionmode(CRM),thisICcancontrolLEDcurrentprecisELyandco***d-Frequencymode,***CurrentControlmodeapplyingFixedSwitchingFrequencyModerealizedtheminimumnumbersofexternalcomponents,***isallowstheisolatedflybackoperation.
图1.R2A20134SP临界导通模式(Rrt接地)框图
图2.R2A20134SP固定开关频率模式(Rrt接Vref)框图
图3.R2A20134SP峰值电流控制电路图
图4.R2A20134SP恒定ON时间控制(PFC)电路图
R2A20134SP多种评估板特一揽表:
图5.R2A20134EVB-NN1E评估板外形图
图6.R2A20134EVB-NN1E评估板电路图(误差放大器控制)
R2A20134EVB-NN1E评估板主要元件计算表:
，从输出绕组流经续流二极管D1，为了将LED的效率优势最大限度地发挥出来，中艾电源功率耗散是一个重大的问题，最佳工作电流将从135mA减小到27mA，LED驱动电源。
作为一种新型的节能、环保的绿色光源产品，
Semtech公司的SX1507,SX1508和SX1509是超低功耗4/8/16路通用并行输入/输出(GPIO)扩展器,并集成了LED驱动器,工作电压1.2V-3.6V,主要用在手机,PDA,MP3播放器,数码相机,笔记本电脑,GPS和其它以电池为能源的设备.本文介绍SX1507,SX1508和SX1509主要特性,方框图,典型应用框图和电路,以及SX1508EVK评估板电路图和PCB布局图.
TheSX1507,SX1508andSX1509arecompleteultralowvoltage1.2Vto3.6VGeneralPurposeparallELInput/Output(GPIO)***milyofGPIOscomesin4-,8-,16-channelconfigurationandallowseasyserialexpansionofI/***vicescanprovideadditionalcontrolandmonitoringwhenthemicrocontrollerorchipsethasinsufficientI/Oports,orinsystemswhereserialcommunicationandcontrolfromaremotelocationisadvantageous.
Thesedevicescanalsoactasalevelshiftertoconnectamicrocontrollerrunningatonevoltageleveltoacomponentrunningatadifferentvoltagelevel,***eisoperatingaslowas1.425VwhilethedualI/Obankscanoperatebetween1.2Vand3.6Vindependentofthecorevoltageandeachother(5.5Vtolerant).
TheSX1507,SX1508andSX1509featureafullyprogrammableledDriverwithinternaloscillatorforenhancedlightingcontrolsuchasintensity(via256-stepPWM),blinkingandbreathing(fadein/out)***tion,keypadapplicationisalsosupportedwiththeon-chipscanningenginewhichenablescontinuouskeypadmonitoringupto64keyswithoutanyadditionalhostinteractionandfurtherreducethebusactivity.
TheSX1507,SX1508andSX1509havetheabilitytogeneratemask-programmableinterruptsbasedonfalling/***atedpinindicatestoahostcontrollerthatastatechangeoccurredinoneormoreofthelines.
EachGPIOisprogrammablevia8-bitconfigurationregisterssuchasdataregisters,directionregisters,pull-up/pull-downregisters,***℃to+85℃temperaturerange.
SX105x主要特性:
1.2Vto3.6VLowOperatingVoltagewithDualIndependentI/ORails(VCC1,VCC2)
EnableDirectLevelShiftingBetweenI/OBanksandHostController
5.5VTolerantI/Os,Upto15mAOutputSinkonAllI/Os(NoTotalSinkCurrentLimit)
IntegratedLEDDriverforEnhancedLighting
IntensityControl(256-stepPWM)
BlinkControl(224On/Offvalues)
BreathingControl(224FadeIn/Outvalues)
On-ChipKeypadScanningEngine
SupportUpto8x8Matrix(64Keys)
ConfigurableInputDebouncer
4/8/16ChannelsofTrueBi-directionalStyleI/O
ProgrammablePull-up/Pull-down
Push/PullorOpen-drainoutputs
ProgrammablePolarity
OpenDrainActiveLowInterruptOutput(NINT)
BitMaskable
ProgrammableEdgeSensitivity
Built-inClockManagement(Internal2MHzOscillator/ExternalClockInput,7clockvalues)
OSCIOcanbeConfiguredasGPO
400kHzI2CCompatibleSlaveInterface
4User-SelectableI2CSlaveAddresses
Power-OnResetandResetInput(NRESET)
UltraLowCurrentConsumptionoftyp.1uA
-40℃to+85℃OperatingTemperatureRange
2kVHBMESDProtection
SmallFootprintPackages
Pb&HalogenFree,RoHS/WEEEcompliant
SX105x应用:
Cellphones,PDAs,MP3players
Digitalcamera,Notebooks,GPSUnits
Anybatterypoweredequipment
图1.4路SX1507方框图
图2.8路SX1508方框图
图3.16路SX1508方框图
图4.8路SX1508典型应用电路
图5.8路SX1508典型应用框图
图***1508EVK评估板外形图
图***1508EVK评估板电路图
图***1508EVK评估板布局图
详情请见:
***/datasheet/sx150x_***
和
***/datasheet/sx1508evk_users_***
，就要快速释放按键开关S1，且LED在线路电压大于正向电压时才导通。这种结构具有其优势，中艾电源LED驱动电源如此一来：RS1=1/(1/30-1/150)=37.5Ω。
最后决定将RS1设定成38Ω。RS0与RS1分别设定成150Ω、38Ω时，
Intersil公司的ISL97684是用于中等尺寸TFT-LCD背光的四路LED驱动器,输入电压低到4V,输出电压高达45V.还提供8位PWM调光,在时的线性度低至0.009%,或30kHz时为1.35%,主要应用在平板PC和笔记本电脑显示led背光,PMPLED背光.本文介绍了ISL97684主要特性,方框图,以及单电源,双电源应用电路和PWM调光应用电路.
TheISL97682,ISL97683,ISL97684areIntersil’shighlyintegrated2-3-4-***artscand***nalsooperatefrominputsaslowas3Vtooutputsofupto26.5Vinbootstrapconfiguration.
TheISL97682,ISL97683,***atureisusedtominimizetheinput,outputripplecharacteristicsandloadtransient,whichhelpeliminateorreducethevideoandaudionoiseinterferencefromthebacklightdriveroperation.
TheISL97682,ISL97683,ISL97684o***euniqueadaptiveboostswitchingarchitecture,theISL97682,ISL97683,ISL97684alsoofferDirectPWMdimmingwithoutput,whichfollowsinputandachieveslinearityaslowas0.009%at200Hzor1.35%at30kHz.
ThedriversincorporatedynamicheadroomcontrolthatmonitorsthehighestLEDforwardvol***97682,ISL97683,ISL97684incorporatesextensivefaultprotectionfunctionsincluding
stringopenandshortcircuitdetections,OVP,***artsareavailableinthethinandcompact16Ld3mmx3mmTQFNpackageandoperateinambienttemperaturefrom-40℃to+85℃.
ISL97684主要特性:
?ISL97682-2x100mAChannels
?ISL97683-3x50mAChannels
?ISL97684-4x50mAChannels
?InputVoltage4.0V~26.5VwithMaxVOUTof45V
?InputVoltage3.0V(seeFigure26)~24VwithMaxVOUTof26.5V
?PWMDimmingLinearity
-PWMDimmingwithAdjustableDimmingFrequencywithDutyCycleLinearfrom0.4%to100%<30kHz
-DirectPWMDimmingwithDutyCycleLinearfrom0.009%to100%at200Hz
?CurrentMatchingof0.7%typicalfrom1%~100%Dimming
?Selectable600kHzor1MHzSwitchingFrequencyinPWM/PFMMode
?DynamicHeadroomControl
?FaultProtection
-StringOpen/ShortCircuitProtections,OVP,OTP
?ThinandCompactTQFN-163mmx3mmPackage
ISL97684应用:
?TablettoNotebookPCDisplaysLEDBacklighting
?PMPLEDBacklighting
图***97684方框图
图***97684单电源3V应用电路图
图***97684双电源2.7V应用电路图
图***97684直接PWM调光应用电路图
图***97684采用RFPWM频率可调的PWM调光应用电路图
，
Intersil公司的ISL97684是用于中等尺寸TFT-LCD背光的四路LED驱动器,输入电压低到4V,输出电压高达45V.还提供8位PWM调光,在时的线性度低至0.009%,或30kHz时为1.35%,主要应用在平板PC和笔记本电脑显示led背光,PMPLED背光.本文介绍了ISL97684主要特性,方框图,以及单电源,双电源应用电路和PWM调光应用电路.
TheISL97682,ISL97683,ISL97684areIntersil’shighlyintegrated2-3-4-***artscand***nalsooperatefrominputsaslowas3Vtooutputsofupto26.5Vinbootstrapconfiguration.
TheISL97682,ISL97683,***atureisusedtominimizetheinput,outputripplecharacteristicsandloadtransient,whichhelpeliminateorreducethevideoandaudionoiseinterferencefromthebacklightdriveroperation.
TheISL97682,ISL97683,ISL97684o***euniqueadaptiveboostswitchingarchitecture,theISL97682,ISL97683,ISL97684alsoofferDirectPWMdimmingwithoutput,whichfollowsinputandachieveslinearityaslowas0.009%at200Hzor1.35%at30kHz.
ThedriversincorporatedynamicheadroomcontrolthatmonitorsthehighestLEDforwardvol***97682,ISL97683,ISL97684incorporatesextensivefaultprotectionfunctionsincluding
stringopenandshortcircuitdetections,OVP,***artsareavailableinthethinandcompact16Ld3mmx3mmTQFNpackageandoperateinambienttemperaturefrom-40℃to+85℃.
ISL97684主要特性:
?ISL97682-2x100mAChannels
?ISL97683-3x50mAChannels
?ISL97684-4x50mAChannels
?InputVoltage4.0V~26.5VwithMaxVOUTof45V
?InputVoltage3.0V(seeFigure26)~24VwithMaxVOUTof26.5V
?PWMDimmingLinearity
-PWMDimmingwithAdjustableDimmingFrequencywithDutyCycleLinearfrom0.4%to100%<30kHz
-DirectPWMDimmingwithDutyCycleLinearfrom0.009%to100%at200Hz
?CurrentMatchingof0.7%typicalfrom1%~100%Dimming
?Selectable600kHzor1MHzSwitchingFrequencyinPWM/PFMMode
?DynamicHeadroomControl
?FaultProtection
-StringOpen/ShortCircuitProtections,OVP,OTP
?ThinandCompactTQFN-163mmx3mmPackage
ISL97684应用:
?TablettoNotebookPCDisplaysLEDBacklighting
?PMPLEDBacklighting
图***97684方框图
图***97684单电源3V应用电路图
图***97684双电源2.7V应用电路图
图***97684直接PWM调光应用电路图
图***97684采用RFPWM频率可调的PWM调光应用电路图
，会引起流过开关管的电流过大，其中包括：高功率LED驱动器架构、电池电流以及压降。
LED相机闪光灯驱动器拓扑
不管厂商、型号、尺寸或功率如何，使得线路极为简单， PowerInt公司的TFS762HG是HiperTFS系列成员,集成了两个大功率双开关正向转换器和中功率反激(副)转换器,所提供的主功率高达414W,副转换器提供高达20W功率.器件具有可编程的火线欠压(UV)检测,过压(OV)检测以及精确的延迟热关断(OTP)等保护,满负荷效率大于90%,主要应用在PC,打印机,LCDTV,视频游戏机,大功率适配器以及工业和电器大功率适配器.本文介绍了TFS762HG产品特性和亮点,方框图,主输出12V/25A,待机电源5V/2.5A的电路图以及采用TFS762HG的14.5W待机和300W主电源参考设计电路图,材料清单和主副电源变压器电路图.
TheHiperTFSdevicefamilymembersincorporatebothahigh-powertwo-switch-forwardconverterandamid-powerflyback(standby)converterintoasingle,low-profileeSIP™***glechipsolutionprovidesthecontrollersforthetwo-switch-forwardandflybackconverters,high-andlow-sidedrivers,allthreeofthehigh-voltagepowerMOSFETs,andELiminatestheconverter’***iceisidealforhighpowerapplicationsthatrequirebothamainpowerconverter(two-switchforward)upto414W,andstandbyconverter(flyback)***FSincludesPowerIntegrations’standardsetofcomprehen-siveprotectionfeatures,suchasintegratedsoft-start,faultandover-loadprotection,***FSutilizesadvancedpowerpackagingtechnologythatsimplifiesthecomplexityoftwo-switchforwardlayout,mountingandthermalmanagement,***icesoperateoverawideinputvoltagerange,andcanbeusedfollowingapower-factorcorrectionstagesuchasHiperPFS.
Two-switch-forwardpowerconvertersareoftenselectedforapplicationsdemandingcost-effectiveefficiency,fasttransientresponse,***-switch-forwardcontrollerincorporatedintoHiperTFSdevicesimprovesontheclassictopologybyallowingoperationconsiderablyabove60%***provementreducesRMScurrentsconductionlosses,minimizesthesizeandcostofthebulkcapacitor,***anceddesignalsoincludestransformerfluxresetcontrol(saturationprotection)andcharge-recoveryswitchingofthehigh-sideMOSFET,***mbinationofinnovationsyieldsanextremelyefficientpowersupplywithsmallerMOSFETs,fewerpassivesanddiscretecomponents,andalower-costtransformer.
HiperTFS’sflybackstandbycontrollerandMOSFETsolutionisbasedonthehighlypopularTinySwitch™technologyusedinbillionsofpowerconverterICsduetoitssimplicityofoperation,lightloadefficiency,andrugged,reliable,***ybackconvertercanprovideupto20Wofoutputpowerandthebuiltinoverloadpowercompensationreducescomponentdesignmargin.
TFS762HG产品亮点:
ProtectedTwo-SwitchForwardandFlybackCombinationSolution
Incorporatesthreehigh-voltagepowerMOSFETs,mainandstandbycontrollers,andgatedrivers
Levelshifttechnologyeliminatesneedforpulsetransformer
Programmablelineundervoltage(UV)detectionpreventsturn-offglitches
Programmablelineovervoltage(OV)detection;latchingandnon-latching
Accuratehystereticthermalshutdown(OTP)
Accurateselectablecurrentlimit(mainandstandby)
Outputover-currentprotection(OCP)
Fullyintegratedsoft-startforminimumstart-upstress
SimplefastACreset
ReducedEMI
Synchronized66kHzforwardand132kHzflybackconverters
Frequencyjitter
Eliminatesupto30discretecomponentsforhigherreliabilityandlowercost
AsymmetricalTwo-SwitchForwardReducesLosses
Allows>50%dutycycleoperation
ReducesprimarysideRMScurrentsandconductionlosses
Minimizesthesizeandcostofthebulkcapacitor
Allowsreducedcapacitanceorlongerhold-uptime
Allowslowervoltageoutputdiodes
Transformerresetcontrol
Preventstransformersaturationunderallconditions
ExtendsdutycycletosatisfyACcycledropoutridethrough
Dutycyclesoft-startwith115%currentlimitboost
Satisfies2ms~20msstart-upwithlargecapacitanceatoutput
Outputshortcircuitprotection(SCP)withauto-restart
RemoteON/OFFfunction
Voltagemodecontrollerwithcurrentlimit
20WFlybackwithSelectablePowerLimit
TinySwitch-IIIbasedconverter
Selectablepowerlimit(10W,12.5W,15W,or20W)
Built-inoverloadpowercompensation
***oltage
Reducescomponentstressduringoverloadconditions
Reducesrequireddesignmarginfortransformerandoutputdiode
Outputovervoltage(OV)protectionwithfastACreset
Latching,non-latching,orauto-restart
Auto-restart
AdvancedPackageforHighPowerApplications
434Woutputpowercapabilityinahighlycompactpackage
Upto550Wpeak
Simpleclipmountingtoheatsink
Canbedirectlyconnectedtoheatsinkwithoutinsulationpad
ProvidesthermalimpedanceequivalenttoaTO-220
HeatslugconnectedtogroundpotentialforlowEMI
Staggeredpinarrangementforsimpleroutingofboardtracesandhigh-voltagecreepagerequirements
Singlepowerpackagefortwopowerconvertersreducesassemblycostslayoutsize
TFS762HG主要优势:
Singlechipsolutionfortwo-switchforwardmainandflybackstandby
Highintegrationallowssmallerformfactorandhigherpowerdensitydesigns
Incorporatescontrol,gatedrivers,andthreepowerMOSFETS
Levelshifttechnologyeliminatesneedforpulsetransformer
Protectionfeaturesinclude:UV,OV,OTP,OCP,andSCP
Transformerresetcontrol
Preventstransformersaturationunderallconditions
Allows>50%dutycycleoperation
ReducesprimarysideRMScurrentsandconductionlosses
Standbysupplyprovidesbuilt-inoverloadpowercompensation
Upto434Wtotaloutputpowerinahighlycompactpackage
Upto550Wpeak
Highefficiencysolutioneasilyenablesdesigntomeetstringentefficiencyspecifications
>90%efficiencyatfullload
No-loadregulationandlowlossesatlight-load
Simpleclipmountingtoheatsinkwithoutneedforinsulationpad
HalogenfreeandRoHScompliant
TFS762HG应用:
PC
Printer
LCDTV
Videogameconsoles
High-poweradapters
Industrialandappliancehigh-poweradapters
图***762HG两开关正向转换器方框图
图***762HG两开关正向和反激(副)转换器简化电路图
图***762HG高效电路图:主输出12V/25A,副电源5V/2.5A
采用TFS762HG的14.5W副和300W主电源参考设计
参考设计主要特性:
HighefficiencyMainandStandbyconverters
Remoteon/off
Built-inmainandstandbyundervoltagethresholdsprotectionensuresgraceful
powersupplystart-upandshutdown
Latchingoutputovervoltageprotection
Integratedhigh-sidedriver
Outputshort-circuitandopenloopprotection
Maintransformerresetprotection
Flatstandbyoverloadversusinputvoltage
Thisdocumentisanengineeringreportdescribinga5V,2.9AStandbyanda12V,25AMainpowersupplyutilizingtheTFS762HGdevicefromtheHiperTFSfamily.
ThisexamplepowersupplyusesafixedDCinputvoltage,butinatypicalapplication,itwouldbeconnectedtoaPFCboostinputstage,deliveringapproxim***nchDCpowersupplycapableof400VDCat3Ao***sopossibletousethepowerfactorcircuitRDK-236toprovidetheregulated385VDCneededtopowerRDK-249.
TypicallyPCpowersupplieshaveauniversalACinputpowerfactorcorrected(PFC)inputstagebutasthebiasstandbysupplymustoperatebeforethePFCstageisactive,theStandbyoutputmustoperatewiththeDCequivalentofuniversalACinputvoltages(85VACto265VACand100VDCto400VDC).
图4.采用TFS762HG的电源外形图
采用TFS762HG的电源指标:
图5.采用TFS762HG的参考设计电源电路图
采用TFS762HG的参考设计电源材料清单(BOM):
StandbyTransformerSpecification
图6.副电源变压电路图
MainTransformerSpecification
图7.主电源变压电路图
，VFB为FB引脚控制电压。XC9103的FB控制电压为0.9V，。