ADIADP8860背景光LED电荷泵驱动方案

ADIADP8860背景光LED电荷泵驱动方案ADI公司的ADP8860是集成了自动光电晶体管控制的可编程背景光LED电荷泵驱动器,能在黑暗和办公室环境光照条件下改变电流强度,从而大大地节省了电源.光强度阈值能通过I2C接口编程,有7路单独和可编程的LED驱动器(6路驱动器电流30mA,1路驱动器为60mA),可编程最大限流有128等级,待机模式电流小于1uA,主要用于移动显示器背景光和手机键盘背景光,双RGB背景光,LED指示器和小型显示器背景光.本文介绍了ADP8860的主要特性,详细的方框图以及典型应用电路,通用应用电路和带键盘光控制的ADP8860应用电路.TheADP8860combinesaprogrammablebacklightLEDchargepumpdriverwithautomaticphototransistorcontrol.Thiscombi-nationallowsforsignificantpowersavingsbecauseitchangesthecurrentintensityinofficeanddarkambientlightconditions.Byperformingthisfunctionautomatically,iteliminatestheneedforaprocessortomonitorthephototransistor.ThelightintensitythresholdsarefullyprogrammableviatheI2Cinterface.Asecondphototransistorinput,withdedicatedcomparators,improvestheambientlightdetectionlevelsforvarioususeroperatingconditions.TheADP8860allowsasmanyassixLEDstobeindependentlydrivenupto30mA(typical).AseventhLEDcanbedrivento60mA(typical).AllLEDsareprogrammableforminimum/max-imumcurrentandfadein/outtimesviatheI2Cinterface.TheseLEDscanalsobecombinedintogroupstoreducetheprocessorinstructionsduringfadein/out.Drivingthisentireconfigurationisatwo-capacitorchargepumpwithgainsof1×,1.5×,and2×.ThissetupiscapableofdrivingamaximumIOUTof240mAfromasupplyof2.5Vto5.5V.Thedeviceincludesavarietyofsafetyfeaturesincludingshort-circuit,overvoltage,andovertemperatureprotection.Thesefeaturesalloweasyimplementationofasafeandrobustdesign.Addi-tionally,inputinrushcurrentsarelimitedviaanintegratedsoftstartcombinedwithcontrolledinput-to-outputisolation.TheADP8860isavailableintwopackagetypes,eitheracompact2mm×2.4mm×0.6mmWLCSP(waferlevelchipscalepackage)orasmallLFCSP(leadframechipscalepackage).ADP8860主要特性:Chargepumpwithautomaticgainselectionof1×,1.5×,and2×formaximumefficiencyUptotwobuilt-incomparatorinputswithprogrammablemodesforambientlightsensingOutdoor,office,anddarkmodesformaximumbacklightpowersavings7independentandprogrammableLEDdrivers6driverscapableof30mA(typical)1drivercapableof60mA(typical)Programmablemaximumcurrentlimit(128levels)Standbymodefor1μAcurrentconsumption16programmablefadeinandfadeouttimes0.1secto5.5secChoosefromlinear,square,orcubicratesFadingoverrideI2C-compatibleinterfaceforallprogrammingDedicatedresetpinandbuilt-inpower-onreset(POR)Short-circuit,overvoltage,andovertemperatureprotectionInternalsoftstarttolimitinrushcurrentsInput-to-outputisolationduringfaultsorshutdownOperationdowntoVIN=2.5Vwithundervoltagelockout(UVLO)atVIN=2.0VSmallwaferlevelchipscalepackage(WLCSP)orleadframechipscalepackage(LFCSP)ADP8860应用:MobiledisplaybacklightingMobilephonekeypadbacklightingDualRGBbacklightingLEDindicationGeneralbacklightingofsmallformatdisplays图1.ADP8860详细方框图图2.ADP8860典型应用电路图3.ADP8860通用应用电路图4.带键盘光控制的ADP8860应用电路AO-Electronics傲壹电子官网：中文网：