Linear-LTCR3805-5-SEPIC-DC電源轉(zhuǎn)換解決方案

LinearLTCR3805-5SEPICDC電源轉(zhuǎn)換解決方案關鍵詞：\o"電源管理"電源管理,\o"DC/DC轉(zhuǎn)換器"DC/DC轉(zhuǎn)換器,\o"SEPIC"SEPIC,Linear公司的LTCR3805-5是可調(diào)頻率電流模式反激/升壓/SEPICDC/DC控制器，工作頻率（70kHz-700kHz）和斜率補償由外接電阻編程，輸出電壓精度±1.5%，主要用在汽車電源，通信電源，隔離的電子設備，家用電器電源和PoE。本文介紹了LTCR3805-5主要特性，方框圖，多種應用電路以及評估板電路圖和材料清單。

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應用：

AutomotivePowerSupplies

TelecomPowerSupplies

IsolatedElectronicEquipment

Auxiliary/HousekeepingPowerSupplies

PoweroverEthernet

圖1。LTCR3805-5方框圖

圖2。LTCR3805-55.5V-40V輸入12V/2A輸出SEPIC轉(zhuǎn)換器電路圖

圖3。LTCR3805-5隔離通信電源18V-72V輸入3.3V/3A輸出電路圖演示板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