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-channELsLEDdriversthataresuitableformediumsizeTFT-LCDbacklights.ThesepartscandrivemultiplechannelsofLEDsfrominputsaslowas4Vtooutputsofupto45V.Theycanalsooperatefrominputsaslowas3Vtooutputsofupto26.5Vinbootstrapconfiguration.
TheISL97682,ISL97683,ISL97684featureoptionalchannelsphaseshiftcontrol.Thisfeatureisusedtominimizetheinput,outputripplecharacteristicsandloadtransient,whichhelpeliminateorreducethevideoandaudionoiseinterferencefromthebacklightdriveroperation.
TheISL97682,ISL97683,ISL97684offer8-bitPWMdimmingforsystemsthatneedfrequencytuningflexibility.Withtheuniqueadaptiveboostswitchingarchitecture,theISL97682,ISL97683,ISL97684alsoofferDirectPWMdimmingwithoutput,whichfollowsinputandachieveslinearityaslowas0.009%at200Hzor1.35%at30kHz.
ThedriversincorporatedynamicheadroomcontrolthatmonitorsthehighestLEDforwardvoltagestringandusesitsfeedbacksignalfortheminimumoutputregulation.TheISL97682,ISL97683,ISL97684incorporatesextensivefaultprotectionfunctionsincluding
stringopenandshortcircuitdetections,OVP,andOTP.Theswitchingfrequencycanbeselectedateither600kHzor1.0MHzinPFMorPWMmode.Thesepartsareavailableinthethinandcompact16Ld3mmx3mmTQFNpackageandoperateinambienttemperaturefrom-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1.ISL97684方框图
图2.ISL97684单电源3V应用电路图
图3.ISL97684双电源2.7V应用电路图
图4.ISL97684直接PWM调光应用电路图
图4.ISL97684采用RFPWM频率可调的PWM调光应用电路图
IsolatedNoOpto-CouplerFlybackControllerwithActivePFC
TheLT®3798isaconstantvoltage/constantcurrentisolatedflybackcontrollerthatcombinesactivepowerfactorcorrection(PFC)withnoopto-couplerrequiredforoutputvoltagefeedbackintoasingle-stageconverter.ALT3798baseddesigncanachieveapowerfactorofgreaterthan0.97byactivELymodulatingtheinputcurrent,allowingcompliancewithmostHarmonicCurrentEmissionrequirements.
TheLT3798iswellsuitedforawidevarietyofoff-lineapplications.TheinputrangecanbescaLEDupordown,dependingmainlyonthechoiceofexternalcomponents.
Efficiencieshigherthan86%canbeachievedwithoutputpowerlevelsupto100watts.Inaddition,theLT3798caneasilybedesignedintohighDCinputapplications.
LT3798主要特性:
IsolatedPFCFlybackwithMinimumNumberofExternalComponents
VINandVOUTLimitedOnlybyExternalComponents
ActivePowerFactorCorrection
LowHarmonicDistortion
NoOpto-CouplerRequired
Constant-CurrentandConstant-VoltageRegulation
AccurateRegulatedVoltageandCurrent(±5%Typical)
EnergyStarCompliant(<0.5WNoLoadOperation)
ThermallyEnhanced16-leadMSOPPackage
LT3798应用:
Offline5Wto100W+Applications
HighDCVINIsolatedApplications
OfflineBusConverter(12V,24Vor48VOutputs)
图1.LT3798方框图
图2.LT3798通用输入24WPFC总线电源电路图
图3.LT3798通用输入48WPFC电源电路图
，特别是在轻载时，当VGS等于零时， Powerint公司的非绝缘12W降压LED驱动器参考设计RDR257是采用LinkSwitch-PH系列LNK405EG器件,极大地简化离线PFCLED驱动器的设计,外接元件极少,功率因素大于0.9.具有非常高的大于85%的效率,在230VAC时的THD小于20%,不需要输出电流检测.本文介绍了LinkSwitch-PH系列产品的亮点,功能方框图,绝缘TRIAC调光高功率因素通用输入14WLED驱动器和绝缘不调光高功率因素通用输入7WLED驱动器,12W降压LED驱动器参考设计RDR257主要特胸,电路图和材料清单.
TheLinkSwitch-PHdramaticallysimplifiesimplementationofLEDdriversrequiringPF>0.9,TRIACdimmercapability(LNK403-409)andhighefficiency.Thesingle-stagePFandconstantcurrentcontrollereliminatespassivecircuitryrequiredforpowerfactorcorrectionandelectrolyticbulkcapacitor.Theadvancedprimary-sidecontroltechniquesusedbytheLinkSwitch-PHdeviceprovideaccurateconstantcurrentcontrolwhileeliminatingtheneedforanoptocouplerandsecondary-sidecurrentcontrolcircuitry.
LinkSwitch-PHincorporatesa725VpowerMOSFET,acontinuous-modePWMcontroller,ahighvoltageswitchedcurrentsourceforselfbiasing,frequencyjittering,cycle-by-cyclecurrentlimitandhystereticthermalshutdowncircuitry,allinamonolithicIC.
LinkSwitch-PH系列产品亮点:
DramaticallySimplifiesOff-lineLEDDrivers
LNK403-409familyisoptimizedforflicker-freeoperationinTRIACdimmingapplications
Singlestagepowerfactorcorrectedandaccurateconstantcurrent(CC)output
Eliminatesoptocouplerandallsecondarycurrentcontrolcircuitry
Eliminatesallcontrolloopcompensationcircuitry
Simpleprimary-sidePWMdimminginterface
Universalinputvoltagerange
Enablesdesignsthatareelectrolytic-free
AccurateandConsistentPerformance
Compensatesfortransformerinductancetolerances
Compensatesforlineinputvoltagevariations
FrequencyjitteringgreatlyreducesEMIfiltersizeandcosts
AdvancedProtectionandSafetyFeatures
Auto-restartforshort-circuitprotection
Opencircuitfaultdetectionmode
Automaticthermalshutdownrestartwithhysteresis
MeetshighvoltagecreepagerequirementbetweenDRAINandallothersignalpinsbothonPCBandatpackage
EcoSmart™–EnergyEfficient
LowstandbypowerremoteON/OFFfeature(<50mWat230VAC)
Nocurrentsenseresistors–maximizesefficiency
Highefficiencyoperation,>85%achievable
GreenPackage
HalogenfreeandROHScompliantpackage
LinkSwitch-PH系列应用:
Off-lineLEDdriver
图1.LinkSwitch-PH系列方框图
图2.绝缘TRIAC调光高功率因素通用输入14WLED驱动器
图3.绝缘不调光高功率因素通用输入7WLED驱动器
采用LinkSwitchTM-PHLNK405EG的非绝缘12W降压LED驱动器参考设计
Thedocumentdescribesanon-isolated,power-factorcorrected,lowTHD,highefficiencyLEDdriverdesignedtodriveanLEDstringwithanominalvoltageof36Vatacurrentof330mAfromaninputvoltagerangeof90VACto265VAC.ItisdesignedtofitinsideaT8tubefixture.
TheLinkSwitch-PHhasbeendevelopedtocosteffectivelydesignasingle-stagepowerfactorcorrectedLEDdriverwithprimary-sideconstantcurrentcontrol.TheLinkSwitch-PHcontrollerwasoptimizedforLEDdriverapplicationswithminimalexternalpartscountandcontroloftheoutputcurrentthroughtheLEDloadwithouttheuseofanoptocoupler.
TheLinkSwitch-PHmonolithicallyintegratesthe725VpowerMOSFETandcontroller.
Thecontrollerconsistsofanoscillator,PWM,6Vregulator,BYPASSpinprogrammingfunctions,over-temperatureprotection,frequencyjittering,cycle-by-cyclecurrentlimit,leadingedgeblanking,andchargecontrollerforoutputCC(constant-current)control.
TheLinkSwitch-PHalsoprovidesasophisticatedrangeofprotectionfeaturesincludingauto-restartforcontrolloopopen/shortfaultsandoutputshort-circuitconditions.AccuratehystereticthermalshutdownensuressafeaveragePCBtemperaturesunderallconditions.
Thenon-isolatedpowerfactorcorrectedbuckpresentedinthisreportshowshowLinkSwitch-PHdramaticallysimplifiesoff-line,high-efficiency,powerfactorcorrectedLEDdriverdesignwithverylowpartscount.
ThisdocumentcontainstheLEDdriverspecification,schematic,PCBdiagram,billofmaterials,conductedEMImeasurements,thermalmeasurements,powerlinetransienttests,inductordocumentationandtypicalperformancecharacteristics.
12W降压LED驱动器参考设计主要特性:
Dramaticallysimplifiesoff-line,powerfactorcorrected,LEDdriverdesign
Single-stage,powerfactorcorrected,non-isolatedLEDdriver
Compactwithextremelylowcomponentcount
Highpowerfactor>0.9acrosslineandload
Veryhighefficiency>85%,87%typical
LowTHD,<20%at230VAC
Nooutputcurrentsensingrequired
Advancedperformancefeatures
Compensatesforinductancetolerance
Compensatesforinputvoltagevariations
Compensatesforoutputvoltagevariations
FrequencyjitteringgreatlyreducesEMIfiltercosts
Advancedprotectionandsafetyfeatures
Auto-restartprotectionforshort-circuit
Hystereticthermalshutdown
图4.12W降压LED驱动器参考设计外形图
参考设计电源指标:
图5.参考设计电路图
参考设计材料清单(BOM):
可选OVP电路材料清单:
参考设计机械元器件清单:
，不同应用对LED电流的要求又各不相同，中艾电源传统的CR模式会存在测试波形不符合实际情况，LED和节能灯都是非线性高频负载[1]，LED驱动电源。 而MBI5026可以看成是由两片74HC595级联构成，公司2011财年(截至2011年1月29日)的收入达36.1亿美元。Marvell在微处理器体系架构及数字信号处理方面的专业知识、超强的模拟及混合信号设计能力，Prema公司的PR4101是大功率LED降压驱动器,能串通方式驱动一个或多个大功率led.工作电压可高达40V,采用外接N沟MOSFET开关管,输出电流可高达1A.可用于卤素灯,通用照明,告警照明,汽车照明,信号指示和LCD背景光.本文介绍了PR4101的主要特性,方框图,典型应用电路,以及采用12/24V电源,12VDC和12VAC电源的PR4101各种应用电路.
HighPowerLEDBuckDriverPR4101
ThePR4101isaLEDbuckdriverfordrivingoneorseveralhighpowerLEDsinseries.
Thesupplyvoltagecanbeupto40V,withanoutputcurrentofmorethan1Ausingan
externalN-channELMOSFETswitchingtransistor.ThePR4101AwithadditionalPWMand
powerdowninputisdeliveredSOP14packaged,whilethePR4101BisofferedSO8
packaged.
PR4101主要特性:
Adjustableoutputcurrentof1Aandmore
Supplyvoltageupto40VbulbreplacementbyLEDs
Dimmingwithphase-cutdimmer
BrightnesscontrolwithPWM(PR4101Aonly)
Outputcurrenttemperaturecompensation
Delayedstartpossible(PR4101Aonly)
Overtemperatureprotection
FrequencyspreadingforimprovedEMI
Lowstandbycurrentof<35μA
Undervoltagelockout
应用:
Halogenlamporfilament
Generalillumination
Warninglights
Automotivelighting
Indicatorsigns
LCDbacklighting
图1.PR4101典型应用电路
图2.PR4101方框图
图3.采用PR4101的12/24V电源的PR4101应用电路
图4.采用12VDC的PR4101应用电路图
图5.采用12VAC的PR4101应用电路
图6.PR4101显示板电路图
详情请见:
http://www.prema.com/pdf/pr4101.pdf，推出各种符合最新LED照明标准的产品，中艾电源LED驱动电源但随温度的上升而减少。在这方面，Linear公司的LT3798是绝缘无光耦带PFC的反激控制器,功率因素大于0.97,不需要光耦合器,谐波低,恒流和恒压调整,精度在±5%,无负载的功耗小于0.5W,和能源之星标准兼容,主要用在离线5W-100W电源,高DCVIN绝缘应用和离线总线转换器(12V,24V或48V输出).本文介绍了LT3798主要特性,框图以及通用输入24W和48WPFC电源电路图.
IsolatedNoOpto-CouplerFlybackControllerwithActivePFC
TheLT®3798isaconstantvoltage/constantcurrentisolatedflybackcontrollerthatcombinesactivepowerfactorcorrection(PFC)withnoopto-couplerrequiredforoutputvoltagefeedbackintoasingle-stageconverter.ALT3798baseddesigncanachieveapowerfactorofgreaterthan0.97byactivELymodulatingtheinputcurrent,allowingcompliancewithmostHarmonicCurrentEmissionrequirements.
TheLT3798iswellsuitedforawidevarietyofoff-lineapplications.TheinputrangecanbescaLEDupordown,dependingmainlyonthechoiceofexternalcomponents.
Efficiencieshigherthan86%canbeachievedwithoutputpowerlevelsupto100watts.Inaddition,theLT3798caneasilybedesignedintohighDCinputapplications.
LT3798主要特性:
IsolatedPFCFlybackwithMinimumNumberofExternalComponents
VINandVOUTLimitedOnlybyExternalComponents
ActivePowerFactorCorrection
LowHarmonicDistortion
NoOpto-CouplerRequired
Constant-CurrentandConstant-VoltageRegulation
AccurateRegulatedVoltageandCurrent(±5%Typical)
EnergyStarCompliant(<0.5WNoLoadOperation)
ThermallyEnhanced16-leadMSOPPackage
LT3798应用:
Offline5Wto100W+Applications
HighDCVINIsolatedApplications
OfflineBusConverter(12V,24Vor48VOutputs)
图1.LT3798方框图
图2.LT3798通用输入24WPFC总线电源电路图
图3.LT3798通用输入48WPFC电源电路图
，
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)expandersidealforlowpowerhandheldbatterypoweredequipment.ThisfamilyofGPIOscomesin4-,8-,16-channelconfigurationandallowseasyserialexpansionofI/Othroughastandard400kHzI2Cinterface.GPIOdevicescanprovideadditionalcontrolandmonitoringwhenthemicrocontrollerorchipsethasinsufficientI/Oports,orinsystemswhereserialcommunicationandcontrolfromaremotelocationisadvantageous.
Thesedevicescanalsoactasalevelshiftertoconnectamicrocontrollerrunningatonevoltageleveltoacomponentrunningatadifferentvoltagelevel,thuseliminatingtheneedforextraleveltranslatingcircuits.Thecoreisoperatingaslowas1.425VwhilethedualI/Obankscanoperatebetween1.2Vand3.6Vindependentofthecorevoltageandeachother(5.5Vtolerant).
TheSX1507,SX1508andSX1509featureafullyprogrammableledDriverwithinternaloscillatorforenhancedlightingcontrolsuchasintensity(via256-stepPWM),blinkingandbreathing(fadein/out)makethemhighlyversatileforawiderangeofLEDapplications.Inaddition,keypadapplicationisalsosupportedwiththeon-chipscanningenginewhichenablescontinuouskeypadmonitoringupto64keyswithoutanyadditionalhostinteractionandfurtherreducethebusactivity.
TheSX1507,SX1508andSX1509havetheabilitytogeneratemask-programmableinterruptsbasedonfalling/risingedgeofanyofitsGPIOlines.Adedicatedpinindicatestoahostcontrollerthatastatechangeoccurredinoneormoreofthelines.
EachGPIOisprogrammablevia8-bitconfigurationregisterssuchasdataregisters,directionregisters,pull-up/pull-downregisters,interruptmaskregistersandinterruptregisters.TheseI/Oexpanderscomeinsmallfootprintpackagesandareratedfrom-40℃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6.SX1508EVK评估板外形图
图7.SX1508EVK评估板电路图
图8.SX1508EVK评估板布局图
详情请见:
http://www.semtech.com/images/datasheet/sx150x_789.pdf
和
http://www.semtech.com/images/datasheet/sx1508evk_users_guide.pdf
U1内的开关导通后，。