DCSwitchingPowerSupplyProtectionTechnologyAbstract：TheDCswitchingpowersupplyprotectionsystem,protectionsystemdesignprinciplesandmachineprotectionmeasures，ananalysisofswitchingpowersupplyintherangeofprotectedcharacteristicsanditsdesignmethodology，introducedanumberofpracticalprotectioncircuit.Keywords:switchingpowersupplyprotectioncircuitsystemdesign1、IntroductionDCswitchingregulatorusedinthepriceofmoreexpensivehigh-powerswitchingdevices,thecontrolcircuitisalsomorecomplex,Inaddition,theloadswitchingregulatorsaregenerallyusedalargenumberofhighlyintegratedelectronicsystemsinstalleddevices.Transistorsandintegrateddevicetoleranceelectricity，lessheatshocks.SwitchingRegulatorsthereforeshouldtakeintoaccounttheprotectionofvoltageregulatorsandloadtheirownsafety.Manydifferenttypesofcircuitprotection，polarityprotection,introducedhere,theprogramprotection,over—currentprotection，over-voltageprotection,under-voltageprotectionandover-temperatureprotectioncircuit.Usuallychosentobesomecombinationofprotection,constitutesacompleteprotectionsystem.2、polarityprotectionDCswitchingregulatorinputaregenerallynotregulatedDCpowersupply.Operatingerrorsoraccidentsasaresultofthesituationwilltakeitswrongpolarity,switchingpowersupplywillbedamaged。Polarityprotectionpurposes，istomaketheswitchingregulatoronlywhenthecorrectpolarityisnotconnectedtoDCpowersupplyregulatortoworkat.SincethediodeDtoflowthroughswitchingregulatorinputtotalcurrent，thiscircuitappliedinalow—powerswitchingregulatormoresuitable.Powerinthelargeroccasion,whilethepolarityprotectioncircuitasaproceduretoprotectalink，savethepowerrequiredforpolarityprotectiondiodes，powerconsumptionwillbereduced.Inordertoeasytooperate，makeiteasiertoidentifythecorrectpolarityornot，collectthenextlight.3、procedurestoprotectSwitchingpowersupplycircuitisrathercomplicated，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→chargemodulationswitchingregulatorcircui...
