LED节能灯电源驱动芯片LM3445资料

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1、LM3445TriacDimmableOfflineLEDDriverOctober9,2009LM3445TriacDimmableOfflineLEDDriverGeneralDescriptionFeaturesTheLM3445isanadaptiveconstantoff-timeAC/DCbuck■TriacdimdecodercircuitforLEDdimming(step-down)constantcurrentcontrollerdesignedtobecom-■Applicationvoltagerange80VAC–270

2、VACpatiblewithtriacdimmers.TheLM3445providesaconstant■CapableofcontrollingLEDcurrentsgreaterthan1AcurrentforilluminatinghighpowerLEDsandincludesatriacdimdecoder.ThedimdecoderallowswiderangeLEDdim-■Adjustableswitchingfrequencymingusingstandardtriacdimmers.Thehighfrequencyca-■L

3、owquiescentcurrentpablearchitectureallowstheuseofsmallexternalpassive■Adaptiveprogrammableoff-timeallowsforconstantripplecomponents.TheLM3445includesableedercircuittoensurecurrentpropertriacoperationbyallowingcurrentflowwhiletheline■Thermalshutdownvoltageislowtoenableproperfi

4、ringofthetriac.Apassive■No120HzflickerPFCcircuitensuresgoodpowerfactorbydrawingcurrentdi-rectlyfromthelineformostofthecycle,andprovidesa■Lowprofile10pinMSOPPackageconstantpositivevoltagetothebuckregulator.Additional■Patentpendingdrivearchitecturefeaturesincludethermalshutdown

5、,currentlimitandVCCun-der-voltagelockout.Applications■RetroFitTriacDimming■SolidStateLighting■IndustrialandCommercialLighting■ResidentialLightingTypicalLM3445LEDDriverApplicationCircuit3006030530060301©2009NationalSemiconductorCorporation300603www.national.comConnectionDiagra

6、mLM3445TopView3006030310-PinMSOPNSPackageNumberMUB10AOrderingInformationOrderNumberSpec.PackageNSCPackageTopMarkSuppliedAsTypeDrawingLM3445MMNOPBMSOP-10MUB10ASULB1000Units,TapeandReelLM3445MMXNOPBMSOP-10MUB10ASULB3500Units,TapeandReelPinDescriptionsPin#NameDescription1ASNSPWM

7、outputofthetriacdimdecodercircuit.Outputsa0to4VPWMsignalwithadutycycleproportionaltothetriacdimmeron-time.2FLTR1Firstfilterinput.The120HzPWMsignalfromASNSisfilteredtoaDCsignalandcomparedtoa1to3V,5.85kHzramptogenerateahigherfrequencyPWMsignalwithadutycycleproportionaltothetria

8、cdimmerfiringangle.Pullabove4.9V(typical)totri-stateDIM.3DIMInput/ou