细数夜明诸大罪状:*利用板猪之权限将自己的圈钱帖置顶*回答问题敷衍了事,忽悠虚心学习者*十大定律害死新人无数*心胸狭隘,满嘴污言秽语,把骂街当专业*提携马仔,小徒弟共同攻击不同的声音*技术论坛炫耀个人工作待遇,财富,侮辱加班者是无能力者

细数夜明诸大罪状:*利用板猪之权限将自己的圈钱帖置顶*回答问题敷衍了事,忽悠虚心学习者*十大定律害死新人无数*心胸狭隘,满嘴污言秽语,把骂街当专业*提携马仔,小徒弟共同攻击不同的声音*技术论坛炫耀个人工作待遇,财富,侮辱加班者是无能力者

嘿嘿,,,,,,,,

这种情况大多数属于后者......

你....你..是不是..那个..叫什么.....葵花宝典的.....什么??你不是....那你是???什么,,比葵花宝典还厉害的.....葵花点穴手....那你...自宫了没有?????

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Fig.1.ThebestMOSFETdriversforhigh-speedswitchingconsistofacombinationbipolarandMOSprocess.TheMOSsectionisplacedinparallelwitheachbipolardevicetoachievetruerail-to-railswitchingbetweenVDDandground.TheresultisasuperiorMOSFETdriveroptimizedforhigh-speedswitchingandtrulyratedtodeliverthefull-currentspecifiedonthedatasheet.InternallyregulatedoradjustablegatedriveSomeMOSFETdriversuseafixedinternalregulatortosettheamplitudeofthegatedrivevoltage.InternallyregulatedgatedrivesshouldbeconsideredwhentheVDDsupplyvoltagetothedriverICisnotwellregulated.TheadvantageisthatthegatedriveamplitudeiswellregulatedandcanbecloselymatchedtoapowerMOSFETofferingoptimalswitchingresults.However,asthegate-to-sourcevoltageofapowerMOSFETisincreased,theon-resistanceisdecreasedresultinginlowerpowerdissipationfromconductionlosses.Conversely,asthegate-to-sourcevoltageisincreased,thepowerlossesassociatedwithgatechargearealsoincreased.Therefore,forconvertersrequiringhighestefficiency,suchasvoltage-regulator-moduleapplications,aMOSFETdriverwithanadjustablegatedrivevoltagemightbalancethegatechargelossesagainstconductionlossesmoreefficiently.PropagationdelayPropagationdelayisthetimeittakestopassasignalfromthedriver'sinputtooutput.WhilepropagationdelayscanaffectthetimingbetweenthePWMandthepowerMOSFET,thedelayisnotaprimaryconcernbecauseitisnormallyaccountedforwithintheconverter'scontrolloop.Forisolatedconvertersusingaprimary-sidePWMcontrollerandasecondary-sidesynchronousrectifierMOSFETdriver,propagationdelaycansignificantlyaffectthetimingoftheprimarytothesecondary.ArequirementforthesetypesofconvertersisthatthetotaldelaytothesecondarysynchronousrectifiersmustbelessthanthedelayfromthePWMthroughthepowertransformer.Usingasecondary-sideMOSFETdriverwithapropagationdelaylargerthantheprimary-sidePWMtoMOSFETdelaycanmakeitdifficulttooptimizethetimingbetweentheprimaryandsecondary.DeadtimecontrolForsynchronousbuckdc/dcconverterapplications,thehigh-sideandlow-sideMOSFETsmustnotbeallowedtoconductsimultaneouslyordestructive"shoot-through"currentscanresult.ThereforeanimportantconsiderationforthesetypesofMOSFETdriversisdeadtimecontrol.Currentdriversofferauser-programmablefixeddelaybetweenthetwodrivesignalsofasynchronousbuck.Theadvantageofthisapproachliesinitssimplicity.Thedisadvantageisthatprogrammingthedeadtimelongenoughtoensurethatcrossconductionwillnotoccurunderalloperatingconditionsresultsinadditionalbody-diodeconductionlossesinthelow-sidesynchronousMOSFET.Others梥uchastheTPS2838/9synchronousbuckdrivers梪seanadaptivegatedrivetechniquetoactivelyadjusttheamountofdeadtimebetweenthehigh-sideandlow-sideMOSFETs.Adaptivegatedrivesensesthedrain-to-sourcevoltageofthelow-sideMOSFETwhileactivelyadjustingthedeadtimetoreducebody-diodeconductionlossesandavoidcross-conduction.Adaptivegatedriveofferssignificantimprovementsoverfixed-delay,butstillsuffersfromthefactthatsomebody-diodeconductionisinevitableduetofinitepropagationdelaysbetweenthetimethatbody-diodeconductionisdetectedandthegatedrivesignalisadjusted.Newdriverstodayalsouseapredictivegatedrivetoovercomethepropagationdelaysassociatedwithadaptivegatedrive.Predictivegatedrivetechnologyisadigital-controltechniquethatvirtuallyeliminatesbody-diodeconductionwhileoptimizingdead-timetogivethehighestpossibleefficiency.PackagingAswithanypowermanagementIC,thejunctiontemperatureofaMOSFETdrivermustbekeptsafelywithinratedlimitsunderalloperatingconditions.Industry-standardpackagessuchasDIP,SOIC,andTSSOParepopularconsiderations,buthigh-currentMOSFETdriversusedinhigh-frequencyapplicationsrequirecarefulconsiderationgiventoadvancedpackagingtechniques.Today'sMOSFETdriversareplacedinTSSOPswithanexposedleadframediepadonthebottomofthepackage.ThisisknownasaPowerPadTSSOP,orHTSSOP,offeringthermalimpedancewithajunction-to-caseratingaslowas2°C/W.ComparedwithaTSSOPwithoutPowerPadoperatingatsimilarjunctiontemperatures,thelowerthermalimpedanceoftheHTSSOPmeansmorepowercanbedissipatedwithinacomparablysizedpackage.Forapplicationswhereminimizingparasiticeffectssuchasstraycapacitanceandleadinductancearecrucialforswitchingperformance,theQFNpackageisamust.QFNpackageshavenomeasurableleadinductance,makingthemidealforhigh-frequencyconverterdesigns.AdditionalconsiderationsSecondaryMOSFETdriverICconsiderationswouldincludeadditional"featuresofconvenience"notassociatedwithdriverperformanceenhancement.ThesemightincludesuchfeaturesasEN(Enable),overvoltageprotection,thermalshutdown,orovercurrentprotection.BecauseMOSFETdriverICsareusedinavarietyofisolatedandnonisolatedpowerconverterapplications,afinalnoteofconsiderationwouldbehavingaccesstoasolidknowledgebaseoftechnicalsupport.Thissupportcanoftenmeanthedifferencebetweendesignsuccessandfailure.