LED分流保护方案(免费)

LSPOpenLEDShuntProtectorOverviewIntroducingtheBourns®LSPOpenLEDShuntProtectorTargetLightingApplicationsLEDOverviewLEDFailureModesOpenLEDFailureLSPxx00SeriesDesignOptionsIntegratedZenerLEDsElectricalCharacteristicsDataSheetParametersCompetitionSummaryTargetLightingApplicationsLCDBacklighting-Televisions-ComputermonitorsTransportLighting-Instrumentationbacklightingforcars,trucks,etcTaillights,brakelightsforcarsandtrucksDashboardbacklighting-AvionicsSignageAmbientlightingInstrumentationIndustrialHighReliabilityLightingLow/ZeroMaintenanceLighting-Streetlighting-TrafficlightsIntrinsicallySafeLighting-Mining-OilExploration-EmergencyLightingDisplayLighting-Food-Refrigeration-SignageLEDCharacteristicsTypicallightingLEDshaveaVfof~3volts.Maximumlightoutputisgovernedbymaximumcurrentcapabilityandtemperature.Accuratecontrolofcurrentisessentialtocontrolpowerandtemperature.Vf=3VoltsIf=350mATypical1WattLEDVoltsLEDLightingSolid-statelightingluminairesarecommonlyconfiguredwithlongstringsofmultipleseriesLEDsdrivenfromarelativelyhighvoltagecompliance,constantcurrentpowersupply.Thisconfigurationhasseveralbenefits:-MultipleLEDscanbearrangedinseriestosimplifythepowersupplydesign.-Highvoltage,lowcurrentpowersupplyimprovesefficiencyofthepowersupply.-Modulardesigncanalloweasyscaling;forexample,using1WLEDs-8W,16W,24Wor32Wdesignscaneasilybecreatedwithmultiplestringsof8x1WLEDs.-OneLEDstreetlightdesignusessixstringsof15LEDsforatotalof90LEDs.CurrentSourceDCsupplyLEDFailureModesTherearethreetypicalfailuremodesofanLED:1)LEDlightoutputdropsastheLEDages.Oncebelowsomeper-centageofitsinitialvalue,theLEDisdeemedtobe“EndofLife”.2)TheLEDdieisdamagedduetoovervoltage,overcurrentorovertemperatureresultinginashortcircuit.3)ThewirebondconnectingtheLEDchiptotheleadframebreaksorburnsopen.CommoncausesincludeoverdissipationoftheLEDcausingtheopticaltransparentlayertomelt.Theforcesofthiscoolingandheatingcandamagethechipwirebond.CurrentSourceDCsupplyDimLEDsShortedLED1openLEDOpenLEDFailureTheLSPisdesignedtomaketheopenLEDfailuremodetolerable.AnopenLEDwillcauseacompleteLEDstringtogodark,renderingtheapplicationuselessormarkedlycompromised.Thiscanleadtowarrantyreturnsormaintenancecalls.TocomplywithEnergyStar*,LEDlightingfixturesmust:-Havea3yearwarranty-Produce70%ofnewlightoutputfor35khours(residential:25k).PlacingaBourns®LSPdeviceacrossLEDsallowstheremainingLEDsinastringtocontinuetoworkwhenanLEDfailsopencircuit.LSPdevicesinactivemodedissipatelesspowerthantheLEDdid.WhilelowpowerLEDstringdesignsmayhaveusedzenerdiodesinthisrole,highpowerLEDswouldrequireverylargeandexpensivezeners.ControlCircuitLSP0600ControlCircuitLSP0600ControlCircuitLSP0600ControlCircuitLSP06001openLEDCurrentSourceDCsupply*EnergyStarV1.1.2008CurrentSourceControlCircuitLSP1800DCsupplyControlCircuitLSP1800LSPxx00SeriesDesignOptionsBourns®LSPdevicescomeinfourvoltageoptionsdesignedtoprotectsubstringsof1,2,3or4LEDs.ProtectingmoreLEDsperLSPminimizescost.However,ifjustoneLEDfailsopen,theentiresubstringwillgodark.CurrentSourceControlCircuitLSP0600ControlCircuitLSP0600ControlCircuitLSP0600ControlCircuitLSP0600LED1LED2LEDnDCsupplyCurrentSourceControlCircuitLSP0900LED1LED2LEDnDCsupplyControlCircuitLSP0900CurrentSourceControlCircuitLSP1300LEDnDCsupplyControlCircuitLSP1300LEDnLSP0600LSP0900LSP1300LSP1800LEDswithIntegratedZenerMostLEDshaveanintegratedZenerforESDprotection.TheintegratedZenercannothandlethefullcurrentoftheLEDstring.Ifawirebondfails,itlikelywouldalsodisconnecttheZener.AnLSPisstillneeded.ElectricalCharacteristicsLSPdevicesemploythyristortechnologysimilartoTISP®devices.WheneverthevoltageacrossthedeviceexceedstheratedV(BO),,thedeviceswitchestoitson-state.Intheon-state,thevoltageacrosstheLSPdevicefallstoabout1volt,minimizingpowerdissipation.TheLSPcanbeoperatedintheon-stateforthelifeofthelightfixture.LEDcontrollersutilizingfastswitchingfordimmingpurposescanstilluseLSPtechnology.DataSheetParametersIDRM-LowstandbycurrentforminimalsystempowerlossV(BO)-Specifiedtomatch1,2,3or4LEDs•MinimumvoltagespecifiednottoclipLEDVf•MaximumvoltageshouldbebelowpowersupplycompliancevoltageI(BO)-SpecifiedbelowtypicalLEDoperatingcurrenttoensuretheLSPxx00alwaysswitcheson,buthighenoughtopreventfalsetriggering.VT-Max.1.2VLEDVfof3VthereforereducesluminairepowerdissipationifLEDfails.SummaryProductApplications-HighReliabilityLEDLightingApplicationsProductSupportAvailable-Datasheet-Samples/DesignKit-FAESupportProductFamilyPartNumberWorkingVoltage(V)NumberofLEDsspannedLSP060061LSP090092LSP1300133LSP1800184Questions?