Linear-LTCR3805-5-SEPIC-DC电源转换解决方案

LinearLTCR3805-5SEPICDC电源转换解决方案关键词：\o"电源管理"电源管理,\o"DC/DC转换器"DC/DC转换器,\o"SEPIC"SEPIC,Linear公司的LTCR3805-5是可调频率电流模式反激/升压/SEPICDC/DC控制器，工作频率（70kHz-700kHz）和斜率补偿由外接电阻编程，输出电压精度±1.5%，主要用在汽车电源，通信电源，隔离的电子设备，家用电器电源和PoE。本文介绍了LTCR3805-5主要特性，方框图，多种应用电路以及评估板电路图和材料清单。

AdjustableFrequencyCurrentModeFlyback/Boost/SEPICDC/DCController

TheLTCR3805-5isacurrentmodeDC/DCcontrollerdesignedtodriveanN-channelMOSFETinflyback,boostandSEPICconverterapplications.Operatingfrequencyandslopecompensationcanbeprogrammedbyexternalresistors.Programmableovercurrentsensingprotectstheconverterfromoverloadandshort-circuitconditions.

Soft-startcanbeprogrammedusinganexternalcapacitorandthesoft-startcapacitoralsoprogramsanautomaticrestartfeature.

TheLTC3805-5provides±1.5%outputvoltageaccuracyandconsumesonly360μAofquiescentcurrentduringnormaloperationandonly40μAduringmicropowerstartup.Usinga9.5Vinternalshuntregulator,theLTC3805-5canbepoweredfromahighVINthrougharesistororitcanbepowereddirectlyfromalowimpedanceDCvoltagefrom4.7Vto8.8V.

TheLTC3805-5isavailableinthe10-leadMSOPpackageandthe3mmx3mmDFNpackage.

LTCR3805-5主要特性：

VINandVOUTLimitedOnlybyExternalComponents

4.5VUndervoltageLockoutThreshold

AdjustableSlopeCompensation

AdjustableOvercurrentProtectionwithAutomaticRestart

AdjustableOperatingFrequency(70kHzto700kHz)WithOneExternalResistor

SynchronizabletoanExternalClock

±1.5%ReferenceAccuracy

Only100mVCurrentSenseVoltageDrop

RUNPinwithPrecisionThresholdandAdjustableHysteresis

ProgrammableSoft-StartwithOneExternalCapacitor

LowQuiescentCurrent:360μA

Small10-LeadMSOPand3mmx3mmDFN

LTCR3805-5应用：

AutomotivePowerSupplies

TelecomPowerSupplies

IsolatedElectronicEquipment

Auxiliary/HousekeepingPowerSupplies

PoweroverEthernet

图1。LTCR3805-5方框图

图2。LTCR3805-55.5V-40V输入12V/2A输出SEPIC转换器电路图

图3。LTCR3805-5隔离通信电源18V-72V输入3.3V/3A输出电路图演示板1576

Demonstrationcircuit1576ishighefficiencynonisolatedSEPIC(SingleEndedPrimaryInductorConverter)converterfeaturingtheLTC3805-5switchingcontroller.TheDC1576converts5Vto30Vinputto12Voutputandprovidesover3Aofoutputcurrent.

Theconverteroperatesat300kHzwithefficiencyover90%.Withproperamountofairflow,theDC1576convertercangenerateover3Aofoutputcurrent.TheDC1576canbeeasilymodifiedtogenerateoutputvoltagesintherangefrom0.8Vto48V.

Also,theDC1576canbemodifiedforotherinputvoltageslike5V-36V,9V-36V,36V-72V,andsoon.Thewiderinputvoltagerangewilldecreasetheconverterefficiency.Therefore,narrowinputvoltagerangewillbemoredesirable.

TheLTC3805-5canbesynchronizedtoanexternalclockofupto400kHz.P