标签: 直流性能比较

Moreandmore,batteryoperatedsystemsarerequiringlowerterminalvoltagestopowerinternalcircuits.Multi-celldesignsarerapidlymigratingtosingle-cellarchitecturestoreducesystemcost.Aprimeexampleofthissystemtypeisdigitalcameras,whichoftenuseasingle-cell3.6VLi-Ionbatteryfortheirpowersource.Digitalcamerascontainhigh-speedmemoryICs,whichrequiretightvoltageregulationatmoderateloadstomeettherequiredtimingparametersofthesystem.Precisionlowdropout(LDO)regulatordevicescanbeusedtomeettheserequirementsbutindoingso,theLDOregulatorsmustbeabletosuccessfullyoperateinthe‘dropout’modeasthebatterydischarges.Dropoutmodeisenteredwhentheinputvoltage(fromthebatterysource)isequaltothe“nominaloutputvoltage”oftheLDO;forexamplea3.3VLDOentersdropoutmodewhenitsinputvoltageattheVINpinisequalto3.3V.MinimaloutputvoltagedroopandminimalLDOpowerdissipationarecriticaltomeetingvarioussystemperformanceparametersandextendingthelifeofthebattery.AN776DCPerformanceComparisonsofCMOSvs.BipolarLDOswhenOperatingin"Dropout"(VIN=NominalVOUT)ModeAuthor:PatrickMaresca,BACKGROUNDINFORMATION:MicrochipTechnology,Inc.CMOSvs.BIPOLARARCHITECTUREFigures1Aand1BcomparetheblockdiagramforacommonbipolarregulatorwiththatofanequivalentregulatorfabricatedinINTRODUCTION……