开关电源中的关键元器件设计(王海杰)OK

PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计王海杰（jack_wang）世纪电源网版主中国电源学会高级会员2009年3月28日|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计•InputFuse•MOV•ELE-Capacitors•PowermosFET•SchottkyDiode•Photocoupler|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计ExampleforfuseEle-characteristics|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计ExampleforfuseSafetyapprovals|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计ExampleforfuseSafetyapprovals|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计I2tExampleforBellfuse5ETSeries|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计I2tExampleforBellfuse5ETSeries|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计SurgecurrentShapeforCombineWaveNote:ShouldSimplyestimatedthemaximumI2tValuewith20uSforDesignMargin.|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计IntroducetoMetalOxideVaristorPartNumbercodeforThinkingMOV|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计IntroducetoMetalOxideVaristorElectricalCharacteristicsofMOV|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计IntroducetoMetalOxideVaristorSafetyApprovalofMOV|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计PowerDeratingvsTemperatureIntroducetoMetalOxideVaristorNote:NeedtocareifsomeMOVshow-40~125DegreeCoperatingrange|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计MaximumSurgeCurrentDeratingcurvesThemaximumcurrentvaluewillsuddenderatewithrepeatedpulseIntroducetoMetalOxideVaristor|PEGASUS开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计IntroducetoMetalOxideVaristorWarning:Around0.1mApeakleakagecurrentwithTVR10471and264Vacinput|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计StructureofAluminumELE-Capacitors|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计TheEquivalentCircuit|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计Measuredatafrequencyof120HzandapplyingamaximumACvoltageof0.5VrmswithaDCbiasvoltageof1.5or2.0V(JISC5101)Typicalcapacitancebehaviorvsfrequency|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计Typicalcapacitancebehaviorvstemperature|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计Lossangletangent(dissipationfactor)|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计Thetangentshowshighervaluesasthemeasuredfrequencyincreasesandthemeasuredtemperaturedecreases.Lossangletangent(dissipationfactor)|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计ImpedanceandESRvsfrequency|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计ImpedancevstempretureTheimpedancevariesmuchduetoESRaffectedbythetemperature|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计ThehighertemperatureandhighervoltagewillaffecttheleakagecurrentLeakagecurrentvstempreture|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计LeakagecurrentvstempretureInfantUsefulWear-out|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计BulkCapacitor-function1.Smoothnesstheinputvoltageripple2.Bufferfortheenergytransfer3.Storageenergyfortheholduptime|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计Busvoltagewaveformandcalculation|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计Uk()k0.40.50.60.70.80.9100.20.40.60.81HoldupTimevs.BusVoltage•EnergyUextractedfromthebuscapacitoris)1(21ThenVkVLet)(21220012120kVCUVVCU−⋅⋅=⋅=−⋅=•Whenthevoltagehaddecayedto70.7%ofitsinitialvalue,halfoftheavailableenergyhasbeenextracted.|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计Vt()t0102030405060080160240320400•Itisnotpaytochoosethefinalvoltagebelow50%.•Allowingalowerfinalvoltagecausethehigherpeakvoltagesonoutputdiode.•Choicedependsonthebalancingcapacitorvaluesanddiodevoltages.•Don’tforgetthetoleranceonthecapacitor(usually+/-20%).•Busvoltagedecaysvstheconstantload•Whenthevoltagedecaysbelow50%,thedownslopebecomesmuchmoresevere.|PEGASUSDesigningfortheELE-Capacitor开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计开关电源中关键元件的设计Note:Theefficiencyhadbeenignoretosimplifythecalculation.NeededcapacitancecalculationmStVdcVk203106.00===WFCkVtPCo/65.0)1(222μ=⇒−⋅⋅=0VVkfinal=()()220212121kVCVVoCtPWfinal