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DCSwitchingPowerSupplyProtectionTechnology

Abstract:TheDCswitchingpowersupplyprotectionsystem,protectionsystemdesignprinciplesandmachineprotectionmeasures,ananalysisofswitchingpowersupplyintherangeofprotectedcharacteristicsanditsdesignmethodology,introducedanumberofpracticalprotectioncircuit.

Keywords:switchingpowersupplyprotectioncircuitsystemdesign

1、Introduction

DCswitchingregulatorusedinthepriceofmoreexpensivehigh-powerswitchingdevices,thecontrolcircuitisalsomorecomplex,Inaddition,theloadswitchingregulatorsaregenerallyusedalargenumberofhighlyintegratedelectronicsystemsinstalleddevices.Transistorsandintegrateddevicetoleranceelectricity,lessheatshocks.SwitchingRegulatorsthereforeshouldtakeintoaccounttheprotectionofvoltageregulatorsandloadtheirownsafety.Manydifferenttypesofcircuitprotection,polarityprotection,introducedhere,theprogramprotection,over-currentprotection,over-voltageprotection,under-voltageprotectionandover-temperatureprotectioncircuit.Usuallychosentobesomecombinationofprotection,constitutesacompleteprotectionsystem.

2、polarityprotection

DCswitchingregulatorinputaregenerallynotregulatedDCpowersupply.Operatingerrorsoraccidentsasaresultofthesituationwilltakeitswrongpolarity,switchingpowersupplywillbedamaged.Polarityprotectionpurposes,istomaketheswitchingregulatoronlywhenthecorrectpolarityisnotconnectedtoDCpowersupplyregulatortoworkat.SincethediodeDtoflowthroughswitchingregulatorinputtotalcurrent,thiscircuitappliedinalow-powerswitchingregulatormoresuitable.Powerinthelargeroccasion,whilethepolarityprotectioncircuitasaproceduretoprotectalink,savethepowerrequiredforpolarityprotectiondiodes,powerconsumptionwillbereduced.Inordertoeasytooperate,makeiteasiertoidentifythecorrectpolarityornot,collectthenextlight.

3、procedurestoprotect

Switchingpowersupplycircuitisrathercomplicated,basicallycanbedividedintolow-powerandhigh-powerpartofthecontrolpartoftheswitch.Switchisahigh-powertransistors,fortheprotectionofthetransistorswitchisturnedonoroffpowersafety,wemustfirstmodulator,amplifierandotherlow-powercontrolcircuit.Tothisend,theboottoensurethecorrectprocedures.SwitchingRegulatorsgenerallytaketheinputofasmallinductor,theinputfiltercapacitor.Momentintheboot,filtercapacitorwillflowalotofsurgecurrent,thesurgecurrentcanbeseveraltimesmorethanthenormalinputcurrent.Suchalargesurgecurrentmaycontactthegeneralpowerswitchorrelaycontactmelting,andtheinputfusefuse.Inaddition,thecapacitorsurgecurrentwilldamagetoshortenthelifespanofprematuredamage.Tothisend,thebootshouldbeaccesstoacurrentlimitingresistor,throughthecurrentlimitingresistortocapacitorcharging.Inordernottomakethecurrentlimitingresistorexcessivepowerconsumption,thusaffectingthenormalswitchingregulator,andthetransientprocessinthebootafterashortperiodthenautomaticallyrelaysittoDCpowersupplydirectlytotheswitchingregulatorpowersupply.Thiscircuitswitchingregulatorcalleda"softstart"circuit.

Switchingregulatorcontrolcircuitofthelogiccomponentsrequiredorop-ampauxiliarypowersupply.Tothisend,theauxiliarypowersupplymustbeintheswitchcircuit.Thiscontrolcircuitcanbeusedtoensuretheboot.Normalbootprocessis:toidentifythepolarityofinputpower,voltageprotectionprocedures→boot→auxiliarypowersupplycircuitandthroughcurrentlimitingresistorRoftheswitchingregulatorinputcapacitorC→chargemodulationswitchingregulatorcircuit,→short-circuitcurrentlimitingresistorstabilityswitchingregulator.

Intheswitchingregulator,themachinesjustbecausetheoutputcapacitance,andchargetotheratedoutputvoltagevalueoftheneedforacertainperiodoftime.Duringthistime,samplingtheoutputamplifierwithlowinputvoltagesampling,closed-loopregulationcharacteristicsofthesystemwillforcetheswitchingofthetransistorconductiontimelengthened,sothatswitchingtransistorduringthisperiodwilltendtocontinuousconduction,andeasilydamaged.Tothisend,therequirementsofthisparagraphintheboottime,theswitchtoswitchtheoutputmodulationcircuittransistorbasedrivesignalofthepulsewidthmodulation,canguaranteetheswitching

Whenplacednearthepowerswitchingtransistororpowerdevice,itwillbeabletoplaytheroleoftemperatureinstructions.Whenthepowercontrolthetemperatureoftheshellortheinternaldevicetemperatureexceedstheallowedvalue,theheatconductionthyristoron,sothatLEDwarninglight.Iftheoptocouplerwith,wouldenablethewholecircuitalarmactiontoprotecttheswitchingregulator.Itcanalsobeusedasapowertransistorastheover-temperatureprotection,crystalswitchthebasecurrentbyn-typegatecontrolthyristorTT201thermalbypass,cut-offswitchtocutoffthecollectorcurrenttopreventoverheating.

8、Conclusion

Discussedaboveintheswitchingregulatorofavarietyofconservation,andintroducesanumberofspecificwaystoachieve.Ofagivenswitchingpowersupplyisconcerned,butalsoprotectionfromthewholetoconsiderthefollowingpoints:

1)theswitchingregulatorusedintheswitchingtransistorintheDCsecurityrestrictionsontheworkofregionalwork.ThetransistorswitchesselectedbythemanualavailabletransistorsgetDCsafeworkingarea.Accordingtothemaximumcollectorcurrenttodeterminetheinputvalueofover-currentprotection.However,theinstantaneousmaximumvalueshouldbeconvertedtotheaveragecurrent.Atratedoutputcurrentandoutputvoltageconditions,theswitchofthedynamicloadlinedoesnotexceedasafeworkingareaDCmaximuminputvoltage,inputover-voltageprotectionisthevoltagevalue.

2)theswitchingregulatoroutputlimitgivenbythetechnicalindicatorswithin.Workwithintherequiredtemperaturerange,theswitchingregulator'soutputvoltage,thelowerlimitoftheoutputisoff,duetothevoltagevalueofvoltageprotection.Over-currentprotectioncanbebasedonthemaximumoutputcurrenttodetermine.Falsealarminordernottoprotectthevalueofacertainmargintoremainappropriate.

3)fromtheabovetwomethodstodeterminetheprotectionafterthepowersupplydeviceinaccordancewiththeneedsofmeasurestodeterminethealarm.Measuresthegeneralalarmsoundandlightalarmtwopolice.Voiceofthepoliceappliedtomorecomplexmachines,powersupplypartsanddonotstandoutinaplace,itcangivestaffaneffectivewarningoffailure;opticalPoliceinstructionscanbeeye-catchingandfaultalarmandpointedoutthatthefaultlocationandtype.Protectionmeasuresshouldbeprotectedastodeterminethelocation.Inthehigh-power,multi-channelpowersupply,alwayspaying,DCcircuitbreakers,relays,etc.high-sensitivityauto-protectionmeasures,tocutofftheinputpowersupplytostopworkingthesystemfromdamage.Throughthelogiccontrolcircuittomaketheappropriateprogramcut-offswitchtransistorissensitiveitisconvenientandeconomic.Thiseliminatedlarg