文献翻译——开关电源设计

第1页外文文献资料SwitchingPowerSupplyDesignSwitchingpowerisworkinthehighfrequency,highpulsestate,areanalogcircuitsinaratherspecialkind.Clothboardstofollowtheprincipleofhigh-frequencycircuitwiring.1.GeneralizationPulsevoltageconnectionasshortaspossible,includinginputswitchconnectedtothetransformer,outputtransformertotherectifiertubecable.Pulsecurrentloopassmallaspossiblesuchastheinputfiltercapacitorisreturnedtothetransformertotheswitchcapacitornegative.Someout-endedoutputtransformersaretheoutputrectifiertotheoutputcapacitorbacktotransformercircuitXcapacitorascloseaspossibletotheinputswitchingpowersupply,inputlinesshouldbeavoidedinparallelwithothercircuits,shouldbeavoided.YcapacitorshouldbeplacedinthechassisgroundterminalorFGconnectors.ThetotaloftouchinductionandtransformertomaintainacertaindistanceinordertoavoidmagneticSuchaspoorhandlingoffeelinginbetweeninductorandtransformerplusashield,overanumberofEMCperformanceforpowersupplytothegreaterimpact.Generaltheoutputcapacitorcanbeusedtheothertwoacloserectifieroutputterminalshouldbecloseto,canaffectthepowersupplyoutputrippleindex,twosmallcapacitorinparallelresultsshouldbebetterthanusingalargecapacitor.Heatingdevicestomaintainacertaindistance,andelectrolyticcapacitorstoextendmachinelife,electrolyticcapacitorsistheswitchingpowersupplybottlenecklife,suchastransformers,powercontrol,highpowerresistorsandelectrolytictomaintainthedistancerequiredbetweentheelectrolyteleavingspaceforheatdissipation,conditionspermitting,maybeplacedintheinlet.Controlparttopayattentionto:Weaksignalhighimpedancecircuit第2页connectedtosamplethefeedbackloopasshortasintheprocessingasfaraspossibleavoidinterference,thecurrentsamplingsignalcircuits,inparticularthecurrentcontrolcircuit,easytodealwithsomeunexpectedbadTheaccident,whichhadsomeskill,nowto3843thecircuitexampleshowninFigure(1)Figure1betterthanYuFigure2,Figure2atfulltimebyobservingthecurrentwaveformoscilloscopesuperimposedspikes,limitedflowratiodesignDianlow,Figure1thereisnosuchphenomenon,thereareswitchdrivesignalcircuit,switchresistanceshouldbeclosetotheswitchdrivercanswitchtheworktoimprovethereliabilityofthisandthehighDCimpedancevoltagepowerMOSFETdrivercharacteristics.2.RoutingAlignmentofcurrentdensity:nowthemajorityofelectroniccircuitboardusinginsulatedcopperconstitutetied.CommonPCBcopperthicknessof35m,thealignmentvaluecanbeobtainedinaccordancewith1A/mmexperiencethevalueofcurrentdensity,thespecificcalculationscanbefoundintextbooks.Toensurethealignmentprinciplesofmechanicalstrengthshouldbegreaterthanorequaltothewidthof0.3mm(othernon-powersupplycircuitboardmaybesmallerminimumlinewidth).PCBcopperthicknessof70misalsocommoninswitchingpowersupply,thenthecurrentdensitycanbehigher.Addthat,nowcircuitboarddesigntooldesignsoftwaregenerallyitemssuchaslinewidth,linespacing,holesizeandsodryplateJinXingparameterscanbeset.Inthedesignofcircuitboards,designsoftwareautomaticallyinaccordancewiththespecifications,cansavetime,reducesomeoftheworkloadandreducetheerrorrate.Generallyhigheronthereliabilityoflinesorlinedensitywiringcanbeuseddoublepanel.Characterizedhasmoderatecost,highreliability,togetmostcost.Theranksofsomeofthepowermoduleproductsarealsousedplywood,mainlytofacilitateintegrationofpowerdevicessuchastransformerinductancetooptimizewiring,coolingandotherpowertube.Goodconsistency第3页withthecraftbeautiful,transformercoolinggoodadvantage,butitsdisadvantageishighcost,poorflexibility,onlysuitableforindustrialmassproduction.Single-sided,themarketcirculationofalmostuniversalswitchingpowersupplyusingsingle-sidedcircuitboard,whichhastheadvantageoflowercostsinthedesignandproductiontechnologyarealsotakensomemeasurestoensureitsperformance.SinglePCBdesigntodaytotalkaboutsomeexperience,asasinglepanelwithlowcost,easy-to-manufacturefeatures,theswitchingpowersupplycircuithasbeenwidelyused,becauseofitssidetiedonlycopper,thedeviceselectricalconnections,mechanicalfixationshouldrelyonthecopperlayer,theprocessingmustbecareful.Toensuregoodperformanceofthemechanicalstructurewelding,single-sidedpadshouldbeslightlylargertoensurethatthecopperandsubstratetiedgoodfocus,andthuswillnotbeshockedwhenthecopperstrip,brokenoff.Generalweldingringwidthshouldbegreaterthan0.3mm.Paddiametershouldbeslightlylargerthanthediameterofthedevicepins,butnottoolarge,toensurepinandpadbythesolderconnectionbetweentheshortestdistance,plateholesizeshouldnothinderthenormalconditionsforthedegreeofinvestigation,thepaddiameterisgenerallygreaterthanpindiameter0.1-0.2mm.Multi-pindevicetoensureasmoothinvestigationdocumentscanalsobelarger.Electricalconnectionshouldbeaswideaspossible,inprinciple,shouldbelargerthanthewidthofpaddiameter,specialcircumstancesshouldbeconnectedinlinewiththeneedtowidentheintersectionpad(commonlyknownasGenerationtears),toavoidbreakingcertainconditions,lineandpad.Principleofminimumlinewidthshouldbegreaterthan0.5mm.Single-boardisclosetothecircuitboard.Needoverheadcoolingdevicetodeviceandcircuitboardbetweenthepinspluscasing,canplayasupportingdeviceandincreasethedualroleofinsulationtominimizeoravoidexternalshocksonthepadandthepinjunctionimpactandenhancethefirmnessofwelding.Circuitboardsupportingtheweightoflargepartscanincreasetheconnectionpoint,canenhancejointstrengthbetweenthecircuit第4页board,suchastransformers,powerdeviceheatsink.Single-sidedweldingpinswithoutaffectingthesurfaceandtheshellspacingofthepriorconditions,itcanbetostaylonger,theadvantageofincreasedstrengthofweldedparts,increaseweldareaandimmediatelyfoundaWeldphenomenon.Shearpinlonglegs,theweldingforcesmallerparts.InTaiwan,theJapaneseoftenusethedevicepinsintheweldingareaandthecircuitboardwasbent45degrees,andthenweldingprocess,itsreasoningIbid.Doublepaneltodaytotalkaboutthedesignofsomeoftheissues,inrelativelyhighnumberofrequests,ortakethelinedensityofthelargerapplicationenvironmentsusingdouble-sidedPCB,itsperformanceandvariousindicatorsofalotbetterthanasinglepanel.Two-panelpadasholeshavebeenhighintensitymetalprocessing,weldingringsmallerthanasinglepanel,thepadholediameterslightlylargerindiameterthanpins,asintheweldingprocesssoldersolutionconducivetopenetratethroughthetopholesolderpadtoincreasetheweldingreliability.Butitisadisadvantageiftheholeistoolarge,wavesolderingtinwhenthejetimpactinthelowerpartofthedevicemaygoup,havesomeflaws.Highcurrenthandlingofalignment,linewidthinaccordancewithpre-quoteprocessing,suchasthewidthisnotenoughtogoonlineingeneralcanbeusedtoincreasethethicknessoftinplatingsolutionthemethodhasagoodvarietyof1.Willtakethelinesettopadproperty,sothatwhenthecircuitboardmanufacturingsolderalignmentwillnotbecovered,thewholehotairnormallybetinplated.2.Inthewiringbyplacingpads,thepadissettotakeinlineshape,payattentiontothepadholessettozero.3.Inthesolderlayerplacedonline,thismethodisthemostflexible,butnotallPCBmanufacturerswillunderstandyourintentions,neededcaptions.Placethelineinthesolderlayerofthesitewillnotcoatedsoldertinninglineseveralmethodsasabove,tonotethat,ifthealignmentofaverywideallplatedwithtininsolderafterthesolderwillbondalotanddistributionisveryuneven,affectingappearance.Articletin第5页canbeusedgenerallyslenderwidthinthe11.5mm,lengthcanbedeterminedaccordingtolines,tinpartoftheinterval0.51mmDouble-sidedcircuitboardforthelayout,thealignmentprovidesaveryselective,makewiringmorereasonable.Ontheground,thepowergroundandsignalgroundmustbeseparated,thetwotoconvergeinfiltercapacitors,inordertoavoidalargepulsedcurrentthroughthesignalgroundconnectioninstabilitycausedbyunexpectedfactors,thesignalcontrolcircuitgroundingpointasfaraspossible,askill,asfaraspossiblethealignmentofthenon-groundedwiringlayerinthesameplace,thelastshopinanotherlayerofearth.Outputlinethroughthefiltercapacitors,thegeneralfirst,andthentotheload,inputlinemustalsopasscapacitor,tothetransformer,thetheoreticalbasisistoripplethroughtripfiltercapacitor.Voltagefeedbacksampling,inordertoavoidhighcurrentthroughthealignmentofthefeedbackvoltageonthesamplingpointmustbethemostperipheralpoweroutputtoincreasetheloadeffectoftargetmachine.Alignmentchangefromawiringlayertoanotherwiringlayergenerallyusedholeconnected,notthroughthepinpaddevicetoachieve,becausethepluginthedevicemaybedamagedwhentherelationshipbetweenthisconnection,thereiscurrentineverypassageof1A,atleasttwothrough-hole,throughholediameterisgreaterthantheprincipleof0.5mm,0.8mmgenerallyprocessedensurereliability.Coolingdevices,insomesmallpowersupply,thecircuitboardtracescanbeandcooling,characterizedbythealignmentasgenerousaspossibletoincreasethecoolingareaisnotcoatedsolder,conditionscanevenbeplacedoverholes,enhancedthermalconductivity.Todayistotalkaboutthealuminumplateintheswitchingpowersupplyapplicationandmultilayerprintedcircuitintheswitchingpowersupplyapplications.Aluminumplatebyitsownhasthefollowingcharacteristics:verygoodthermalconductivity,singlecopper,thedevicecanonlybeplacedintiedcoppersurface,cannotopenelectricalconnectionholesoasnottoplacejumperinaccordancewithasinglepanel.Aluminumplateisgenerallyplacedpatchdevice,switch,theoutput第6页rectifierheatconductionthroughthesubstratetogoout,verylowthermalresistance,highreliabilitycanbeachieved.Transformerwithplanarchipstructure,butalsothroughsubstratecooling,thetemperatureislowerthantheconventional,thesamesizetransformerwithalargealuminumplatestructureavailableoutputpower.Aluminumplatejumperbridgeapproachcanbeused.AluminumplatepoweraregenerallycomposedbythetwoPCB,anotheronetoplacethecontrolcircuitboard,throughthephysicalconnectionbetweenthetwoboardsisintegrated.Astheexcellentthermalconductivityofaluminumplate,inasmallamountofmanualweldingmoredifficult,soldercoolingtoofastandpronetoproblemsofasimpleandpracticalwayofexisting,anironingordinaryiron(preferablytemperatureregulationfunction),overandironforthelast,fixed,andtemperatureto150andabovethealuminumplateontheiron,heatingtime,andthenaffixthecomponentsaccordingtoconventionalmethodsandwelding,solderingirontemperatureisappropriatetothedeviceeasyto,istoohighwhenthedevicemaybedamaged,orevencopperstripaluminumplate,thetemperatureistoolowweldingeffectisnotgood,tobeflexible.Recentyears,withthemulti-layercircuitboardapplicationsinswitchingpowersupplycircuit,printedcircuittransformermakesitpossible,duetomultilayer,smallerspacingalsocantakeadvantageofwindowsection,themaincircuitboardcanbere-Add1-2formedbythemultilayerprintedcoiltousethewindow,thepurposeofreducingcircuitcurrentdensity,duetoadoptprintedcoil,reducingmanualintervention,transformersconsistency,surfacestructure,lowleakageinductance,couplinggood.Becauseofitsmanyadvantages,isconducivetomassproduction,itiswidelyused.Buttheresearchanddevelopmentoflargeinitialinvestment,notsuitableforsmall-scalehealth.Switchingpowersupplyisdividedinto,twoformsofisolationandnon-isolated,isolatedheremainlytotalkaboutswitchingpowersupplytopologiesformbelow,non-specified,aretoisolatethepower.Isolatedpowersupplyinaccordancewiththestructureofdifferentforms,canbedividedintotwocategories:aforwardandflyback.FlybacktransformerprimarysidemeansthatwhentheVice-edgeconductioncut-off,transformer第7页storage.Closeoftheprimary,secondarysideconduction,theenergyreleasedtotheloadofworkstatus,generalconventionalflybackpowermultiplex,twin-tubeisnotcommon.Forwardreferstotheprimaryconductionintransformersecondarysidewhilethecorrespondingoutputvoltageisinducedintotheload,thedirecttransferofenergythroughthetransformer.Accordingtospecificationscanbedividedintoconventionalforward,includingthesingle-transistorforward,DoubleForward.Half-bridge,bridgecircuitsareallforwardcircuit.Forwardandflybackcircuitshavetheirowncharacteristicsintheprocessofcircuitdesigntoachieveoptimalcost-effective,canbeappliedflexibly.Usuallyinthelow-powerflybackcanbeadopted.Slightlylargerforwardcircuitcanuseasingletube,medium-powercanuseDoubleForwardcircuitorhalf-bridgecircuit,low-voltagepush-pullcircuit,andthehalf-bridgeworkinthesamestate.Highpoweroutput,generallyusedbridgecircuit,lowvoltagecanbeappliedpush-pullcircuit.Flybackpowersupplybecauseofitssimplestructure,andtocutthesizeofasimilarsizeandtransformerinductance,thepowersupplyinthemediumhasbeenwidelyapplied.Presentationreferredtoinsomeflybackpowersupplycandodozensofwatts,outputpowerexceeding100wattswouldbenoadvantagetothemdifficult.Undernormalcircumstances,Ithinkso,butitcannotbegeneralized,PIsTOPchipscando300watts,anarticledescribestheflybackpowersupplycanbeontheKW,butnotseeninkind.Flybackpowertransformerleakageinductanceisacriticalparameter,becausethepowerneedsoftheflybacktransformerstoredenergy,tomakefulluseoftransformercore,thegeneralmustbeopeninthemagneticcircuitairgap,theaimistochangethecorehysteresisbacklineoftheslope,sothattransformerscanwithstandtheimpactofalargepulsecurrent,whichisnotcoreintosaturationnon-linearstate,themagneticcircuitinthehighreluctanceairgapinthestate,generatedinthemagneticfluxleakageismuchlargerthancompletelyclosedmagneticcircuit.Transformercouplingbetweenthefirstisthekeyfactordeterminingtheleakageinductance,thecoiltobeverycloseasfaraspossiblethefirsttime,thesandwichcanbeusedaroundthelaw,butthiswouldincreasethe第8页distributedcapacitancetransformer.Usecoreascorewithalongwindow,canreducetheleakageinductance,suchastheuseofEE,EF,EER,PQ-basedEItypemagneticcoreeffectivethangood.Thedutycycleofflybackpowersupplies,inprinciple,themaximumdutycycleofflybackpowersupplyshouldbelessthan0.5,otherwisenoteasyloopcompensationmaybeunstable,buttherearesomeexceptions,suchastheU.S.PIhasintroducedtheTOPserieschipcanworkundertheconditionsofdutycycleisgreaterthan0.5.Dutycyclebythetransformerturnsratiotodetermineformerdeputyside,Iamananti-shockviewis,firstdeterminethereflectedvoltage(outputvoltagereflectedthroughthetransformercouplingtheprimaryvoltagevalue),reflectingacertainvoltagerangeofvoltageincreaseisdutycycleincreases,lowerpowerloss.Reducethereflectedvoltagedutycycledecreases,increasespowerloss.Ofcourse,thisisaprerequisite,whenthedutycycleincreases,itmeansthattheoutputdiodeconductiontime,inordertomaintainoutputstability,moretimewillbetoensurethattheoutputcapacitordischargecurrent,theoutputcapacitorwillbeunderevengreaterhigh-frequencyripplecurrenterosion,whileincreasingitsheat,whichinmanycircumstancesisnotallowed.Dutycycleincreases,changethetransformerturnsratio,transformerleakageinductancewillincrease,itsoverallperformancechange,whentheleakageinductanceenergylargeenough,canswitchtofullyoffsetthelargeaccountspacetobringlow-loss,nofurtherincreasewhenthemeaningofduty,becausetheleakageinductancemayevenbetoohighagainstthepeakvoltagebreakdownswitch.Leakageinductanceislarge,maymaketheoutputripple,andotherelectromagneticindicatorsdeteriorated.Whenthedutyhours,thehighRMScurrentthroughtheswitch,transformerprimarycurrentandloweredtheconverterefficiency,butcanimprovetheworkingconditionsoftheoutputcapacitortoreducefever.Howtodeterminethetransformerreflectedvoltage(dutycycle)Peoplesaidpowersupplyfeedbackloopparametersettings,workstatusanalysis.Sincehighschoolmathematicsisratherpoor,AutomaticControlTheory,almostonthemake-up,andforthedoorisstillfeelingfear,and第9页nowcannotwriteacompleteclosed-loopsystemtransferfunction,zeroforthesystem,theconceptoffeelingpolevague,seeBodeplotisonlyabouttoseeisadivergenceorconvergence,sothefeedbackcompensationcannotnonsense,butthereareanumberofrecommendations.Ifyouhavesomemathematicalskills,andthenhavesometimetolearnthentheUniversityof,PrinciplesofAutomaticControldigestlookcarefullytofindout,combinedwithpracticalswitchingpowersupplycircuit,accordingtotheworkofstateforanalysis.Willbeharvested,theForumhasamessage,coachfeedbacklooptostudythedesign,debugging,inwhichCMGgoodanswer,Ithinkwecanreference.Thentoday,onthedutycycleofflybackpowersupply(Iamconcernedaboutthereflectedvoltage,consistentwiththedutycycle),thedutycyclewiththevoltageselectionswitchisrelatedtosomeearlyflybackswitchingpowersupplyusingalowpressuretube,suchas600Vor650VAC220Vinputpowerasaswitch,perhapswhentheproductionprocess,highpressuretubes,easytomanufacture,orlow-pressurepipesaremorereasonableconductionlossesandswitchingcharacteristics,asthislinereflectedvoltagecannotbetoohigh,otherwisetheworkordertoswitchthesecuritycontextoflossofpowerabsorbingcircuitisquiteimpressive.Reflectedvoltage600Vtubeprovednotmorethan100V,650Vtubereflectedvoltagenotgreaterthan120V,theleakageinductancevoltagespikewhenthetubesareclampedat50V50Vworkingmargin.NowthattheMOSraisethelevelofmanufacturingprocesscontrol,flybackpowersuppliesaregenerallyused700Vor750Vor800-900Vtheswitch.Likethiscircuit,overvoltagecapabilityagainstanumberofswitchingtransformerreflectedvoltagecanbedoneabithigher,themaximumreflectedvoltageinthe150Visappropriate,toobtainbetteroverallperformance.Buthisevaluationboardgenerallyreflectedvoltagetobelowerthanthevalueataround110V.Bothtypeshavetheiradvantagesanddisadvantages:Category:shortcomingsagainstover-voltage,lowdutycycleissmall,alargepulsecurrenttransformerprimary.Advantages:smalltransformerleakageinductance,electromagneticradiationandlowrippleindexhigherswitchloss,theconversionefficiencyisnotnecessarilylowerthanthe第10页second.Thesecondcategory:alargenumberofshortcomingsofpowerloss,alargenumberoftransformerleakageinductance,therippleworse.Advantages:Somestrongagainstover-voltage,largedutycycle,lowertransformerlossesandefficiencyhigher.Reflectedvoltageflybackpowersupplywithaparameterrelatedtothatistheoutputvoltage,outputvoltage,thelowerthelargerthetransformerturnsratio,thegreaterthetransformerleakageinductance,switchtowithstandhighervoltagebreakdownswitchispossibletoabsorbpowerconsumptionishigher,hasthepotentialtopermanentlyabsorbthecircuitpowerdevicefailure(particularlywithtransientvoltagesuppressiondiodecircuits).Inthedesignoflow-voltagelow-powerflybackpoweroutputoptimizationprocessmustbehandledwithcare,itsapproachhasseveral:1,usingalargecoreofapowerlevellowerleakageinductance,whichcanimprovethelow-voltageflybackpowerconversionefficiency,reducelosses,reduceoutputrippleandimprovemulti-outputpowerofthecrossregulationingeneraliscommoninhouseholdapplianceswithaswitchpower,suchasCD-ROMdrive,DVBset-topboxes.2,iftheconditionswerenotincreasedcore,canreducethereflectedvoltage,reducingthedutycycle.Reducethereflectedvol