简单的同步降压转换器设计- mcp1612

Thedensityofportableelectronicequipmentrequires

thedesignengineertopayparticularattentiontoa

numberofimportantdesignparameters.Forthepower

conversioncircuitry,twooftheseparametersarethe

efficiencyandthetotalcircuitryfootprint.Keepingthe

efficiencyhighextendsbatterylifeandcontrolsthe

temperatureriseoftheequipment.Limitingthecircuitry

footprinthelpsminimizethesizeofthePrintedCircuit

Board(PCB)and,ultimately,thetotalcostofthe

device.

TheMCP1612isanidealchoiceforsuchadesign.

SinceboththeswitchingandsynchronousMOSFETs

areinternalandswitchingis1.4MHz,theinductor,

inputandoutputcapacitorsizeisminimized.The

outputvoltageissetbyusingasimpleresistordivider,

withahigh-bandwidthloopbeingaccomplishedbya

seriesresistorcapacitortoground.Efficienciesof90%

andatypicalshutdowncurrentof0.01µAhelpto

extendbatterylife.

ThisApplicationNotecontainsalloftheinformation

neededtodesignasynchronousbuckconverterusing

theMCP1612.Italsocontainsareal-worlddesign

examplewithmeasuredlaboratorydata.AN968SimpleSynchronousBuckConverterDesign-MCP1612Author:CliffEllisonSolvingthestandardinductorequationforinductorMicrochipTechnologyInc.ripplecurrent(IL)yields:VLIL=------×TLINTRODUCTION