High-Frequency and High-Performance VRM Design

High-FrequencyandHigh-PerformanceVRMDesignfortheNextGenerationsofProcessorsbyKaiweiYaoDissertationsubmittedtotheFacultyoftheVirginiaPolytechnicInstituteandStateUniversityinpartialfulfillmentoftherequirementsforthedegreeofDoctorofPhilosophyinElectricalEngineeringFredC.Lee,ChairmanDushanBoroyevichAlexQ.HuangGuo-QuanLuYiluLiuApril14,2004Blacksburg,VirginiaKeywords:powermanagement,voltageregulatormodule,highfrequencyCopyright2004,KaiweiYaoHigh-FrequencyandHigh-PerformanceVRMDesignfortheNextGenerationsofProcessorsbyKaiweiYaoFredC.Lee,ChairmanElectricalEngineering(ABSTRACT)ItisperceivedthatMoore’sLawwillprevailatleastforthenextdecadewiththecontinuousadvancementofprocessingtechnologiesforintegratedcircuits.AccordingtoIntel’sroadmap,overonebilliontransistorswillbeintegratedinoneprocessorbytheyear2010;theprocessor’sclockspeedwillapproach15GHz;thecorestaticcurrentswillincreaseupto200A;thedynamiccurrentslewratewillriseupto250A/ns;andthecorevoltagewilldecreaseto0.8V.Therapidadvancementofprocessortechnologyhasposedstringentchallengestopowermanagementforbothanefficientpowerdeliveryandanaccuratevoltageregulation.Theprimaryobjectivesofthisdissertationaretounderstandthefundamentallimitationsofthestate-of-the-artsolutionforthepowermanagement,andhencetosupportpossiblesolutionsformeetingthepowerrequirementofthenextgenerationsofprocessors.First,today’svoltage-regulatormodule(VRM)design,whichisbasedonthemultiphaseinterleavingbucktopology,isthoroughlyanalyzed.TheanalysisresultsofthecontrolbandwidthsversustheVRMtransientvoltagespikeshighlightthetrendofhigh-frequencyVRMdesignforsmallersizeandfastertransientresponse.BasedontheconceptofachievingconstantVRMoutputimpedance,designguidelinesareproposedfordifferentkindsofcontrolmethods.However,thehighswitching-relatedlossesintheconventionalmultiphasebuckconverterlimitiiiitsfurtherapplications.Thisdissertationproposesaseriesofnewtopologiesinordertobreakthroughthebarriersbyapplyinganinductor-couplingorautotransformerstructuretoreducetheswitching-relatedlossesbyextendingthedutycycle.Then,thisdissertationpushesthetopologyinnovationfurtherbyintroducingsoft-switchingquasi-resonantconvertersfortheVRMdesign.Thecombinationofthequasi-resonantandactive-clampedconceptsderivesafamilyofnewconverters,whichcaneliminatealltheswitchingandbody-diodelosses.Theexperimentalresultsat1-2MHzswitchingfrequenciesprovethattheproposedsolutionsfortheVRMdesigncanrealizeveryhighefficiencyandhighpowerdensity.ivTomyparentsQingzhouYaoandYaxianXieAndtomywifeRaoShenvAcknowledgmentsIwouldliketoexpressmysincereappreciationtomyadvisor,Dr.FredC.Lee,forhisguidance,encouragementandsupport.Dr.Lee’sextensivevisionandcreativethinkinghavebeenthesourceofinspirationformethroughoutthiswork.Itwasaninvaluablelearningexperiencetobeoneofhisstudents.FromhimIhavegainednotonlyextensiveknowledge,butalsoacarefulresearchattitude.Iamgratefultomycommitteemembers,Dr.DushanBoroyevich,Dr.AlexQ.Huang,Dr.Guo-QuanLuandDr.YiluLiu,fortheirvaluablesuggestionsandhelp.IthasbeenagreatpleasuretoworkintheCenterforPowerElectronicsSystems(CPES).IwouldliketoacknowledgetheCPESadministrativeandmanagementstaff,Ms.AnnCraig,Ms.LindaGallagher,Ms.TeresaShaw,Ms.ElizabethTranter,Ms.TrishRose,Ms.MarianneHawthorne,Ms.MichelleCzamanske,Mr.DavidFuller,Mr.RobertMartin,Mr.SteveZ.Chen,Mr.DanHuff,Mr.GaryKerrandMr.JamieEvans,fortheircountlessinstancesofhelp.IwouldliketothankmyteammatesintheVRMgroup,Dr.XunweiZhou,Dr.PitleongWong,Dr.PengXu,Dr.MingXu,Dr.BoYang,Mr.JiaWei,Mr.MaoYe,Mr.JinghaiZhou,Ms.LiMa,Mr.YuanchengRen,Mr.YuMeng,Mr.YangQiu,Mr.KisunLi,Mr.DougSterkandMr.XingZhang.Itwasapleasuretoworkwithsuchatalented,hard-workingandcreativegroup.viMyheartfeltappreciationgoestowardmyparents,whohavealwaysencouragedmetopursuehighereducation.Withmuchlove,Iwouldliketothankmywife,RaoShen,whohasalwaysbeentherewithherloveandencouragement.ThisworkwassupportedbytheVRMconsortium(Intel,IBM,DeltaElectronics,TexasInstruments,STMicroelectronics,NationalSemiconductor,Intersil,TDK,Hitachi,Hipro,Power-One,InfineonandArtesyn).Also,thisworkmadeuseofERCsharedfacilitiessupportedbytheNationalScienceFoundationunderAwardNumberEEC-9731677.viiTableofContentsChapter1.Introduction.......................................................................................11.1.ResearchBackground................................................................................................11.2.State-of-the-ArtTechnology.....................................................................................41.3.TechnologyBarriersforFuturePowerManagement............................................91.4.TheWorkofthisDissertation.................................................................................18Chapter2.TheImpactoftheControlBandwidthontheVRMTransientVoltageSpikes.................................................................................202.1.TheReasonforTransientVoltageSpikes.............................................................202.2.TheInductorCurrentSlewRate..............................................