LinearLTC3569中功率降压DC电源转换方案

LinearLTC3569中功率降压DC电源转换方案关键词：电源管理,AC/DC转换器,电源转换Linear公司的LTC3569包含三个同步降压DC/DC转换器,适合中功率应用.输入电压从2.5V到5.5V,工作频率从1MHz到3MHz,三个输出电压是相互独立的:一个输入1.2A,两个输出600mA,静态电流低于100μA.LTC3569可用于需要多个电源的手提设备,通用降压DC/DC转换器以及动态电压缩放应用.本文介绍了LTC3569的主要特性,方框图以及典型应用,双路降压DC/DC稳压器和双路可编程降压D/DC稳压器电路图.TheLTC3569containsthreemonolithic,synchronousstep-downDC/DCconverters.Intendedformediumpowerapplications,itoperatesovera2.5Vto5.5Vinputvoltagerange.Theoperatingfrequencyisadjustablefrom1MHzto3MHz,allowingtheuseoftiny,lowcostcapacitorsandinductors.ThethreeoutputvoltagesareindependentlyprogrammablebytogglingtheENpinsupto15times,loweringthe800mVFBreferencesby25mVpercycle.Thefirstbuckregulatorsourcesloadcurrentsupto1200mA.Theothertwobuckregulatorseachprovide600mA.Thetwo600mAbuckregulatorscanalsobeconfiguredtooperateasslavepowerstages,runninginparallelwithanotherinternalbuckregulatortosupplyhigherloadcurrents.Whenoperatingasparallel,slaveoutputstages,discreteexternalcomponentsaresharedandavailableoutputcurrentssumtogether.LTC3569主要特性:ThreeIndependentCurrentModeBuckDC/DCRegulators(1.2Aand2x600mA)SinglePinProgrammableVFBServoVoltagesfrom800mVDownto425mV(in25mVSteps)nPullVFBHightoMakeEach600mABuckaSlaveforHigherCurrentOperationPulseSkiporBurstModeOperationProgrammableSwitchingFrequency(1MHzto3MHz)orFixed2.25MHzSynchronizable(1.2MHzto3MHz)VINRange2.5Vto5.5VAllRegulatorsInternallyCompensatedPGOODOutputFlagQuiescentCurrent100μA(AllRegulatorsinBurstModeOperation)ZeroShutdownCurrentOvertemperatureandShort-CircuitProtectionTiny3mm×3mm20-LeadQFNandThermallyEnhancedTSSOPFE-16PackagesLTC3569应用:PortableApplicationswithMultipleSupplyRailsGeneralPurposeStep-DownDC/DCDynamicVoltageScalingApplications图1.LTC3569方框图图2.LTC3569降压方框图图3.LTC3569典型应用AO-Electronics傲壹电子官网：中文网：稳压器:1.8V/1800mA和1.5V/600mA图3.采用LTC3569双路可编程降压D/DC稳压器:1200mA,1200mA图4.采用LTC3569双路可编程DC/DC稳压器