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I.IntroductionThe74HC595isan8-bitserial-inorparallel-outshiftregisterwithastorageregisterand3-stateoutputs.74HC595withthecharacteristicsofhighspeed,lowpowerconsumptionandsimpleoperation,canbeeasilyusedinMCUinterfacetodriveLEDoperation.ThisarticleintroducesthecircuitdesignofLEDdisplaydrivedby74HC595.CatalogI.IntroductionII.BasicDescription2.1LEDDisplay2.274HC595III.CircuitDesign3.1HardwareCircuit3.2DisplayDriverIV.ConclusionFAQOrdering&QuantityII.BasicDescription2.1LEDDisplayA7SegmentLEDDisplay,alsoknownasLEDdisplay,hasbeenwidelyusedinvariousinstrumentsbecauseofitslowprice,lowpowerconsumptionandreliableperformance.TherearemanytypesofLEDdriversonthemarket,andmostofthemhavemultiplefunctions,butthepriceiscorrespondinglyhigher.Ifusedinasimplesystemwithlowcost,itisnotonlyawasteofresources,butalsoincreasesthecostofproducts.Using74HC595chiptodriveLEDhasvariousdisadvantages.Highspeed,lowpowerconsumption,unlimitednumberofLEDs.ItcancontrolboththecommoncathodeLEDdisplayandthecommonanodeLEDdisplay.Thecircuitdesignedwith74HC595isnotonlysimple,butalsolowinpowerconsumptionandstrongindrivingability.Itisalowcostandflexibledesignscheme.2.274HC595The74HC595isan8-bitserial-in/serialorparallel-outshiftregisterwithastorageregisterand3-stateoutputs.Boththeshiftandstorageregisterhaveseparateclocks.Thedevicefeaturesaserialinput(DS)andaserialoutput(Q7S)toenablecascadingandanasynchronousresetMRinput.ALOWonMRwillresettheshiftregister.DataisshiftedontheLOW-to-HIGHtransitionsoftheSHCPinput.ThedataintheshiftregisteristransferredtothestorageregisteronaLOW-to-HIGHtransitionoftheSTCPinput.Ifbothclocksareconnectedtogether,theshiftregisterwillalwaysbeoneclockpulseaheadofthestorageregister.Datainthestorageregisterappearsattheoutputwhenevertheoutputenableinput(OE)isLOW.AHIGHonOEcausestheoutputstoassumeahigh-impedanceOFF-state.OperationoftheOEinputdoesnotaffectthestateoftheregisters.Inputsincludeclampdiodes.ThisenablestheuseofcurrentlimitingresistorstointerfaceinputstovoltagesinexcessofVCC.Figure1.74HC595FunctionalDiagramFigure2.74HC595LogicSymbolIII.CircuitDesign3.1HardwareCircuitFigure3isadisplaypanelcircuitdesignedwithAT89C2051and74HC595interface.Figure3.CircuitofDisplayPanelTheP115,P116,andP117oftheP1portareusedtocontrolthedisplayoftheLED,andtheyareconnectedtotheSLCK,SCLKandSDApinsrespectively.Threedigitaltubesareusedtodisplaythevoltagevalue.Onthecircuitboard,LED3isonthefarleftandLED1isonthefarright.Whensendingdata,firstsendthedisplaycodeofLED3,andfinallysendthedisplaycodeofLED1.ThebrightnessoftheLEDiscontrolledbytheresistanceofPR1toPR3.2.2DisplayDriverUseDISP1,DISP2,andDISP3tostoredisplaydata.AftertheCPUinitializationiscomplete,calltheLRDISPsubroutinetocleartheregisterof74HC595.ThereisnoneedtocalltheclearsubroutinebeforecallingthedisplaysubroutineDISPLAY.Nowwritethetwosubroutinesasfollows.①CLRDISP:MOVR2,#24CLRBIT:CLRSCLKCLRCMOVSDA,CSETBSCLKDJNZR2,CLRBITRET②Display:CLRSLCKMOVR3,#3MOVR0,#DISP3DISP1:MOVA,@R0MOVR2,#8DISP2:CLRSCLKRLCAMOVSDA,CSETBSCLKDJNZR2,DISP2DECR0DJNZR3,DISP1SETBSLCKRETIV.ConclusionItcanbeseenfromtheaboveexamplesthattherearenocomplicatedtechnicalproblemsinthedesignofhardwareandsoftwarewhen74HC595isusedtodesignLEDdrivercircuit.Inaddition,74HC595canbeusednotonlytodriveLEDdisplays,butalsotodrivelight-emittingdiodes.Each74HC595candrive8LEDssimultaneously.Thissolutionisidealwhenthevolumerequirementsoftheproductarenothighandwanttoreducethecost.FAQWhatis74HC595?74HC595isashiftregisterwhichworksonSerialINParallelOUTprotocol.Itreceivesdataseriallyfromthemicrocontrollerandthensendsoutthisdatathroughparallelpins.Wecanincreaseouroutputpinsby8usingthesinglechip.Whatisa74hc595n?8-bitShiftRegister74HC595NAshiftregisterisachipyoucanusetocontrolmanyoutputs(8here)atthesametimewhileonlyusingafewpins(3here)ofyourArduino.Howdoesashiftregisterwork?Shiftregistersholdthedataintheirmemorywhichismovedorshiftedtotheirrequiredpositionsoneachclockpulse.Eachclockpulseshiftsthecontentsoftheregisteronebitpositiontoeithertheleftortheright.How74HC595ShiftRegiesterworks?The595hastworegisters(whichcanbethoughtofasmemorycontainers),eachwithjust8bitsofdata.ThefirstoneiscalledtheShiftRegister.TheShiftRegisterliesdeepwithintheICcircuits,quietlyacceptinginput.Howdoesan8bitshiftregisterwork?TheSN74HC595Nisasimple8-bitshiftregisterIC.Simplyput,thisshiftregisterisadevicethatallowsadditionalinputsoroutputstobeaddedtoamicrocontrollerbyconvertingdatabetweenparallelandserialformats.YourchosenmicroprocessorisabletocommunicatewiththeTheSN74HC595Nusingserialinformationthengathersoroutputsinformationinaparallel(multi-pin)format.Essentiallyittakes8bitsfromtheserialinputandthenoutputsthemto8pins.

I.IntroductionThe74HC595isan8-bitserial-inorparallel-outshiftregisterwithastorageregisterand3-stateoutputs.74HC595withthecharacteristicsofhighspeed,lowpowerconsumptionandsimpleoperation,canbeeasilyusedinMCUinterfacetodriveLEDoperation.ThisarticleintroducesthecircuitdesignofLEDdisplaydrivedby74HC595.CatalogI.IntroductionII.BasicDescription2.1LEDDisplay2.274HC595III.CircuitDesign3.1HardwareCircuit3.2DisplayDriverIV.ConclusionFAQOrdering&QuantityII.BasicDescription2.1LEDDisplayA7SegmentLEDDisplay,alsoknownasLEDdisplay,hasbeenwidelyusedinvariousinstrumentsbecauseofitslowprice,lowpowerconsumptionandreliableperformance.TherearemanytypesofLEDdriversonthemarket,andmostofthemhavemultiplefunctions,butthepriceiscorrespondinglyhigher.Ifusedinasimplesystemwithlowcost,itisnotonlyawasteofresources,butalsoincreasesthecostofproducts.Using74HC595chiptodriveLEDhasvariousdisadvantages.Highspeed,lowpowerconsumption,unlimitednumberofLEDs.ItcancontrolboththecommoncathodeLEDdisplayandthecommonanodeLEDdisplay.Thecircuitdesignedwith74HC595isnotonlysimple,butalsolowinpowerconsumptionandstrongindrivingability.Itisalowcostandflexibledesignscheme.2.274HC595The74HC595isan8-bitserial-in/serialorparallel-outshiftregisterwithastorageregisterand3-stateoutputs.Boththeshiftandstorageregisterhaveseparateclocks.Thedevicefeaturesaserialinput(DS)andaserialoutput(Q7S)toenablecascadingandanasynchronousresetMRinput.ALOWonMRwillresettheshiftregister.DataisshiftedontheLOW-to-HIGHtransitionsoftheSHCPinput.ThedataintheshiftregisteristransferredtothestorageregisteronaLOW-to-HIGHtransitionoftheSTCPinput.Ifbothclocksareconnectedtogether,theshiftregisterwillalwaysbeoneclockpulseaheadofthestorageregister.Datainthestorageregisterappearsattheoutputwhenevertheoutputenableinput(OE)isLOW.AHIGHonOEcausestheoutputstoassumeahigh-impedanceOFF-state.OperationoftheOEinputdoesnotaffectthestateoftheregisters.Inputsincludeclampdiodes.ThisenablestheuseofcurrentlimitingresistorstointerfaceinputstovoltagesinexcessofVCC.Figure1.74HC595FunctionalDiagramFigure2.74HC595LogicSymbolIII.CircuitDesign3.1HardwareCircuitFigure3isadisplaypanelcircuitdesignedwithAT89C2051and74HC595interface.Figure3.CircuitofDisplayPanelTheP115,P116,andP117oftheP1portareusedtocontrolthedisplayoftheLED,andtheyareconnectedtotheSLCK,SCLKandSDApinsrespectively.Threedigitaltubesareusedtodisplaythevoltagevalue.Onthecircuitboard,LED3isonthefarleftandLED1isonthefarright.Whensendingdata,firstsendthedisplaycodeofLED3,andfinallysendthedisplaycodeofLED1.ThebrightnessoftheLEDiscontrolledbytheresistanceofPR1toPR3.2.2DisplayDriverUseDISP1,DISP2,andDISP3tostoredisplaydata.AftertheCPUinitializationiscomplete,calltheLRDISPsubroutinetocleartheregisterof74HC595.ThereisnoneedtocalltheclearsubroutinebeforecallingthedisplaysubroutineDISPLAY.Nowwritethetwosubroutinesasfollows.①CLRDISP:MOVR2,#24CLRBIT:CLRSCLKCLRCMOVSDA,resettable thermal fuseCSETBSCLKDJNZR2,piezoelectric pressure sensorsCLRBITRET②Display:CLRSLCKMOVR3,what is eeprom#3MOVR0,how do inductors work#DISP3DISP1:MOVA,presision resistors@R0MOVR2,smd resistors code#8DISP2 :CLRSCLKRLCAMOVSDA,CSETBSCLKDJNZR2,DISP2DECR0DJNZR3,DISP1SETBSLCKRETIV.ConclusionItcanbeseenfromtheaboveexamplesthattherearenocomplicatedtechnicalproblemsinthedesignofhardwareandsoftwarewhen74HC595isusedtodesignLEDdrivercircuit.Inaddition,74HC595canbeusednotonlytodriveLEDdisplays,butalsotodrivelight-emittingdiodes.Each74HC595candrive8LEDssimultaneously.Thissolutionisidealwhenthevolumerequirementsoftheproductarenothighandwanttoreducethecost.FAQWhatis74HC595?74HC595isashiftregisterwhichworksonSerialINParallelOUTprotocol.Itreceivesdataseriallyfromthemicrocontrollerandthensendsoutthisdatathroughparallelpins.Wecanincreaseouroutputpinsby8usingthesinglechip.Whatisa74hc595n?8-bitShiftRegister74HC595NAshiftregisterisachipyoucanusetocontrolmanyoutputs(8here)atthesametimewhileonlyusingafewpins(3here)ofyourArduino.Howdoesashiftregisterwork?Shiftregistersholdthedataintheirmemorywhichismovedorshiftedtotheirrequiredpositionsoneachclockpulse.Eachclockpulseshiftsthecontentsoftheregisteronebitpositiontoeithertheleftortheright.How74HC595ShiftRegiesterworks?The595hastworegisters(whichcanbethoughtofasmemorycontainers),eachwithjust8bitsofdata.ThefirstoneiscalledtheShiftRegister.TheShiftRegisterliesdeepwithintheICcircuits,quietlyacceptinginput.Howdoesan8bitshiftregisterwork?TheSN74HC595Nisasimple8-bitshiftregisterIC.Simplyput,thisshiftregisterisadevicethatallowsadditionalinputsoroutputstobeaddedtoamicrocontrollerbyconvertingdatabetweenparallelandserialformats.YourchosenmicroprocessorisabletocommunicatewiththeTheSN74HC595Nusingserialinformationthengathersoroutputsinformationinaparallel(multi-pin)format.Essentiallyittakes8bitsfromtheserialinputandthenoutputsthemto8pins.

DescriptionUC3842isacurrentcontrolpulsewidthmodulationchipwithexcellentperformance.UC3842modulatorsingle-endedoutputcandirectlydriveabipolarpowertubeorfield-effecttube.CatalogUC3842BDocumentsandMediaUC3842BAdvantagesUC3842BFeaturesUC3842BSimplifiedBlockDiagramUC3842BPinoutUC3842BPackageInformationUC3842BBlockDiagramUC3953BTimingDiagramUC3953BPackagesUC3842BCircuitProductManufacturerOrdering&QuantityUC3842BDocumentsandMediaPCNAssembly/OriginPDIP-8AssemblyRevised03/Sep/2013DatasheetsUC384(2,3)B,UC284(2,3)BHTMLDatasheetUC384(2,3)B,UC284(2,3)BEnvironmentalInformationMaterialDeclarationUC3842BNGEDA/CADModelsDownloadfromUltraLibrarianOnlineCatalogMulti-TopologyUC3842BAdvantagesTheUC3842B,UC3843Bseriesarehighperformancefixedfrequencycurrentmodecontrollers.TheyarespecificallydesignedforOffLineandDCDCconverterapplicationsofferingthedesigneracosteffectivesolutionwithminimalexternalcomponents.Theseintegratedcircuitsfeatureatrimmedoscillatorforprecisedutycyclecontrol,atemperaturecompensatedreference,highgainerroramplifier,currentsensingcomparator,andahighcurrenttotempoleoutputideallysuitedfordrivingapowerMOSFET.Alsoincludedareprotectivefeaturesconsistingofinputandreferenceundervoltagelockoutseachwithhysteresis,cyclebycyclecurrentlimiting,programmableoutputdeadtime,andalatchforsinglepulsemetering.Thesedevicesareavailableinan8pindualinlineandsurfacemount(SOIC8)plasticpackageaswellasthe14pinplasticsurfacemount(SOIC14).TheSOIC14packagehasseparatepowerandgroundpinsforthetotempoleoutputstage.TheUCX842BhasUVLOthresholdsof16V(on)and10V(off),ideallysuitedforofflineconverters.TheUCX843BistailoredforlowervoltageapplicationshavingUVLOthresholdsof8.5V(on)and7.6V(off).UC3842BFeaturesTrimmedOscillatorforPreciseFrequencyControlOscillatorFrequencyGuaranteedat250kHzCurrentModeOperationto500kHzAutomaticFeedForwardCompensationLatchingPWMforCycleByCycleCurrentLimitingInternallyTrimmedReferencewithUndervoltageLockoutHighCurrentTotemPoleOutputUndervoltageLockoutwithHysteresisLowStartupandOperatingCurrentThisisaPbFreeandHalideFreeDeviceUC3842BSimplifiedBlockDiagramUC3842BPinout8Pin14PinFunctionDescription11CompensationThispinistheErrorAmplifieroutputandismadeavailableforloopcompensation.23VoltageFeedbackThisistheinvertinginputoftheErrorAmplifier.Itisnormallyconnectedtotheswitchingpowersupplyoutputthrougharesistordivider.35CurrentSenseAvoltageproportionaltoinductorcurrentisconnectedtothisinput.ThePWMusesthisinformationtoterminatetheoutputswitchconduction.47RT/CTTheOscillatorfrequencyandmaximumOutputdutycycleareprogrammedbyconnectingresistorRTtoVrefandcapacitorCTtoground.Operationto500kHzispossible.5GNDThispinisthecombinedcontrolcircuitryandpowerground.610OutputThisoutputdirectlydrivesthegateofapowerMOSFET.Peakcurrentsupto1.0Aaresourcedandsunkbythispin.712VCCThispinisthepositivesupplyofthecontrolIC.814VrefThisisthereferenceoutput.ItprovideschargingcurrentforcapacitorCTthroughresistorRT8PowerGroundThispinisaseparatepowergroundreturnthatisconnectedbacktothepowersource.Itisusedtoreducetheeffectsofswitchingtransientnoiseonthecontrolcircuitry.11VCTheOutputhighstate(VOH)issetbythevoltageappliedtothispin.Withaseparatepowersourceconnection,itcanreducetheeffectsofswitchingtransientnoiseonthecontrolcircuitry.9GNDThispinisthecontrolcircuitrygroundreturnandisconnectedbacktothepowersourceground.2,4,6,13NCNoconnection.Thesepinsarenotinternallyconnected.UC3842BPackageInformationDocumentTitleDocumentID/SizeRevisionRevisionDate8LEADPDIP626-05(51kB)POct,2019SOIC-14NB751A-03(49kB)LOct,2019SOIC-8NarrowBody751-07(53kB)AKOct,2019UC3842BBlockDiagramUC3953BTimingDiagramUC3953BPackagesUC3842BCircuitOscillatorConfigurationExternalClockSynchronizationExternalDutyCycleClampandMulti-UnitSynchronizationAdjustableReductionofClampLevelSoft-StartCircuitAdjustableBufferedReductionofClampLevelwithSoft-StartCurrentSensingPowerMOSFETCurrentWaveformSpikeSuppressionMOSFETParasiticOscillationsBipolarTransistorDriveIsolatedMOSFETDriveLatchedShutdownErrorAmplifierCompensationSlopCompensation27WOff-LineFlybackRegulatorProductManufacturerONSemiconductor(Nasdaq:ON)isdrivingenergyefficientinnovations,empoweringcustomerstoreduceglobalenergyuse.Thecompanyoffersacomprehensiveportfolioofenergyefficientpowerandsignalmanagement,logic,discreteandcustomsolutionstohelpdesignengineerssolvetheiruniquedesignchallengesinautomotive,communications,computing,consumer,industrial,LEDlighting,medical,military/aerospaceandpowersupplyapplications.ONSemiconductoroperatesaresponsive,reliable,world-classsupplychainandqualityprogram,andanetworkofmanufacturingfacilities,salesofficesanddesigncentersinkeymarketsthroughoutNorthAmerica,Europe,andtheAsiaPacificregions.IDescriptionThisblogintroducesasimplemethodtodrivesteppermotorsusingL297andL298chips.Thesteppingmotordrivesystemdesignedbythismethodhasthefollowingcharacteristics:simplehardwarestructure,easysoftwareprogrammingandlowprice.IDescriptionIIIntroductionIIIL297andL298Hardwarecircuit3.1L297Overview3.2L298Overview3.3L297andL298CircuitIVSoftwaredesignFAQOrdering&QuantityIIIntroductionSteppermotorisoneofthecommonlyusedembeddedmotioncontrolequipmentinindustrialcontrol.Thisisbecausesteppermotorscanmoveatdiscretesteps,provideaccurateangularpositioninformation,andareeasiertocontrol.WiththeuseofL297andL298chipstogether,arelativelylowpricecanbeusedtoformasteppermotordrivecircuitwithgoodperformance.StandardsteppermotordriverusingL297andL298ICIIIL297andL298Hardwarecircuit3.1L297OverviewL297isasteppermotorcontroller.Itissuitableforthecontrolofbipolartwo-phasesteppermotorsorunipolarfour-phasesteppermotors.Therearethreedrivemodes:half-step,full-step,andwave.Theon-chipPWMchoppercircuitallowsswitchingcontrolofthewindingcurrent.Anotablefeatureofl297isthatonlyclock,direction,andmodeinputsignalsarerequired.Thephaserequiredbythesteppingmotorisgeneratedinsidethecircuit,whichgreatlyreducestheburdenontheCPU.L297hasthefollowingcharacteristics:Normal/wavedriveHalf/fullstepmodesClockwise/anticlockwisedirectionSwitchmodeloadcurrentregulationProgrammableloadcurrentFewexternalcomponentsResetinputhomeoutputEnableinput3.2L298OverviewL298isahigh-voltageandhigh-currentdualfull-bridgedriverwithtwoH-bridges.ItacceptsstandardTTLlogiclevelsignalsandcandrivesteppermotorswithavoltageof46Vand2.5Aperphaseorbelow.Eachbridgehasanenableinput,whichallowsorprohibitsthedevicetoworkwithoutbeingaffectedbytheinputsignal.Theemittersofthetwolow-endtransistorsofeachbridgeareconnectedtogetherandledoutforexternaldetectionresistance.Itsetsanadditionalpowerinputterminaltomakethelogicpartworkatlowvoltage.Figure1.L298internallogicdiagram(halfofthediagram)L298hasthefollowingcharacteristics:Operatingsupplyvoltageupto46vTotalDCcurrentupto4A25wratedpower2enablecontrolterminalstoenableordevicewithoutinputtingsignals.Abletodriveatwo-phasesteppermotor,four-phasesteppermotorortwoDCmotorsBuilt-instabilivolttube78M05canbeusedtoobtain5vfrompowersupply.(Mustbeusedwithanexternal5vlogicsupplywhendrivevoltageisgreaterthan12vtoprotectthechip)LowsaturationvoltageOvertemperatureprotectionLogical0inputvoltageupto1.5V(highnoiseimmunity)Operatingtemperature:-23Cto130CStorageTemperature:-40Cto150C3.3L297andL298CircuitL297andL298canbeusedtomakeatwo-phasebipolarsteppermotordrivecircuit.Itisdrivenbyaconstantcurrentmode,andthepeakcurrentofeachphasecanreach2A.L297isasteppermotorcontrollerthatisusedtogeneratetwo-phasebipolar.Drivesignal(A,B,C,D)andmotorcurrentsettings.L298isusedtodrivethepoweroutputofthesteppermotor.Itisdrivenbyadoublefullbridgemode.Duetothebipolardrive,themotorcoilisfullyutilizedtoenableintothemotorcanachievethebestdrive.WhentwopiecesofL297areusedtodrivethetwowindingsofasteppingmotorthroughL298,andtheVrefcorrespondingtoeachwindingischangedthroughtwoD/Aconverters,asteppingmotorsubdivisiondrivingcircuitisformed.TheprincipleofL297+L298drivewiringisshowninFigure2.PortsP0~P4arerespectivelyconnectedtothecorrespondingcontrolterminalsofL297.Then,throughthereasonablearrangementofthesoftware,thepurposeofcontrollingthemotortorotateintheexpecteddirectionisachieved.Figure2.ElectricalschematicdiagramInaddition,theterminal1ofL297isthesynchronousterminal,whichcanbeconnectedtotheterminal1ofanothergroupofL297andL298drivecircuits.Inthisway,thetwosetsofdriverscanbesynchronizedtoachievetheeffectofdrivingmultiplemotorsatthesametime.IVSoftwaredesignUseClanguagetowriteprogramcode:P0_0=1;//CWP0_1~1;//HALFP0_3=1;//ENABLEP0_2=1;//RESETP0_7=1;//CLOCKTMODone0X01;//TlTH0=(a4000/256);TL0=one(4000%256);TR0=1;for(;;){TH0=one(4000/256);TL0=one(4000%256);do{}while(!TF0);P0_7=!P0_7;//CLOCKTF0=0;}Thespeedofthemotorspeedcanbecontrolledbythetimer.Figure3.WaveformdiagramgeneratedbyL297AccordingtothewaveformgeneratedbyL297,infact,whentheCPUportresourcesarenottight,theCPUcanbeusedtosimulateoutput.Theabovehardwarecircuitsandsoftwareprogramshavebeentestedandarecompletelypractical.FAQWhatisl298n?ThisL298NMotorDriverModuleisahighpowermotordrivermodulefordrivingDCandStepperMotors.ThismoduleconsistsofanL298motordriverICanda78M055Vregulator.L298NModulecancontrolupto4DCmotors,or2DCmotorswithdirectionalandspeedcontrol.WhatisL297?TheL297integratesallthecontrolcircuitryrequiredtocontrolbipolarandunipolarsteppermotors.UsedwithadualbridgedriversuchastheL298Nformsacompletemicroprocessor-to-bipolarsteppermotorinterface.Howdoesl298ncontrolDCmotorspeed?1.IfyousendaHIGHsignaltotheenable1pin,motorAisreadytobecontrolledandatthemaximumspeed;2.IfyousendaLOWsignaltotheenable1pin,motorAturnsoff;3.IfyousendaPWMsignal,youcancontrolthespeedofthemotor.Themotorspeedisproportionaltothedutycycle.Whatisl298nmotordrivermodule?ThisL298NMotorDriverModuleisahighpowermotordrivermodulefordrivingDCandStepperMotors.ThismoduleconsistsofanL298motordriverICanda78M055Vregulator.L298NModulecancontrolupto4DCmotors,or2DCmotorswithdirectionalandspeedcontrol.Howdoesl298nmotordriverwork?TheL298NisadualH-BridgemotordriverwhichallowsspeedanddirectioncontroloftwoDCmotorsatthesametime.ThemodulecandriveDCmotorsthathavevoltagesbetween5and35V,withapeakcurrentupto2A.Howdoiuseal298motordriverwithArduino?Startbyconnectingpowersupplytothemotors.InourexperimentweareusingDCGearboxMotors(alsoknownasTTmotors)thatareusuallyfoundintwo-wheel-driverobots.Theyareratedfor3to12V.So,wewillconnectexternal12VpowersupplytotheVCCterminal.WhatisthefunctionofHbridge?AnH-bridgeisanelectroniccircuitthatswitchesthepolarityofavoltageappliedtoaload.ThesecircuitsareoftenusedinroboticsandotherapplicationstoallowDCmotorstorunforwardsorbackwards.Whatistheuseofl298n?TheL298NisadualH-BridgemotordriverwhichallowsspeedanddirectioncontroloftwoDCmotorsatthesametime.ThemodulecandriveDCmotorsthathavevoltagesbetween5and35V,withapeakcurrentupto2A.

LOG14

I.IntroductiontoGalvanometerThegalvanometerisanimportanttestinginstrument.Itisahigh-sensitivitymechanicalindicatingmeterfordetectingweakelectricity.Itisusedasazero-pointinginstrumentinbridgesandpotentiometers.Itcanalsobeusedtomeasureweakcurrents,voltagesandcharges..Accordingtotheinputmode,itcanbedividedintovoltagetypeandcurrenttype.Generally,voltagetypeismorecommonlyused.Fromthepaneldisplaymodeofthegalvanometer,itcanbedividedintothreetypes:pointertype,digitaltype,andmixedtype.Figure1ThegalvanometerThepointergalvanometercanconvenientlyobservethecontinuouslychangingcurrent,andintuitivelyjudgethedirectionofthecurrentfromthedeflectiondirection,soithasitsuniqueadvantagesinthebridgeexperiment.Thepointergalvanometerscurrentlyusedinphysicalexperimentshavethefollowingshortcomings:(1)Use9Vlaminatedbatterywithsmallcapacity,shortbatterylifeandhighcost;(2)ItsinternalamplifyingcircuitadoptsOP07orICL7650design,withoutpowermanagementcapability,itiseasytocausethebatterytobeconsumedunnecessarily;(3)Duetotheuseofmanydiscretecomponents,theamplifierispronetodriftandunstable.Thispaperusesagalvanometerdesignedbasedonthethree-op-amphighcommon-moderejectionratioandhighstabilityinstrumentationamplifierAD620andMicrochips6-pinMCUPIC10F206tosolvetheaboveproblems.CatalogI.IntroductiontoGalvanometerII.HardwareSystemDesign2.1HardwareSystemBlockDiagram2.2InstrumentationAmplifierAD6202.3MicrocontrollerPIC10F2062.4AmplifyingCircuitofGalvanometer2.5PowerMonitoringandPowerManagementCircuitofGalvanometerIII.SoftwareSystemIV.ConclusionFAQOrdering&QuantityII.HardwareSystemDesign2.1HardwareSystemBlockDiagramTheblockdiagramofthehardwaresystemisshowninFigure2.TheDCvoltagesignalfirstpassesthroughananti-radiofrequencyinterferencelow-passfiltercircuit,weakenstheinterferencesignal,andthensendsittotheinstrumentationamplifierAD620fordifferentialamplification,andthendrivesthepointermetertodisplay.The6-pinmicrocontrollerPIC10F206isresponsibleforthepowermonitoringandpowermanagementofthegalvanometer.Thewholegalvanometeronlyuses3VDCpowersupplyconnectedinserieswithtwoAAbatteries.Figure2Thehardwaresystemblockdiagramofthegalvanomete2.2InstrumentationAmplifierAD620AD620isalow-costandhigh-precisioninstrumentationamplifierlaunchedbytheAmericanADIcompany.Ithasthecharacteristicsofhighaccuracy,lowoffsetvoltage(maximum50uV)andlowoffsetdrift(maximum0.6uV℃/),anditsmaximumoperatingcurrentisonly1.3mA,onlyanexternalresistorisneededtosetthegain,andthegainrangeis1to10000.Inaddition,AD620adopts8-pinSOICandDIPpackage,thesizeissmallerthanthediscretecircuitdesign,andthepowerconsumptionislower,soitissuitableforbattery-poweredinstrumentapplications.Figure3AD620BecauseitsinputstageusesSuperetaprocessing,itcanachievealowinputbiascurrentofupto1.0nA.AD620hasalowinputvoltagenoiseof9nV/Hzat1kHz,apeak-to-peaknoiseof0.28Vinthefrequencybandfrom0.1Hzto10Hz,andaninputcurrentnoiseof0.1pA/Hz,soitcanbeusedasapreamplifierwell.Atthesametime,the0.01%settlingtimeofAD620is15s,whichisverysuitableformultiplexingapplications;andthecostisverylow,enoughtorealizethedesignofaninstrumentationamplifierperchannel.2.3MicrocontrollerPIC10F206PIC10F206isalow-cost,6-pin8-bitflashmicrocontrollerintroducedbytheUSMicrochipcompanythatusesRISCarchitecture.PIC10F206has512wordsofFLASH,24bytesofSRAM,watchdogtimer(WDT),power-onresetcircuit(POR)anddeviceresettimer(DRT)and4MHzinternaloscillator,thuseliminatingtheneedforexternalresetcircuitandthecrystaloscillator,reducessystemcostandpowerconsumption,andenhancessystemreliability.Italsohasawideoperatingvoltagerange(20Vto5.5V).Theabovecharacteristicsmakeitsuitableforapplicationsinprice-sensitiveandbattery-poweredareas.Figure4PIC10F2062.4AmplifyingCircuitofGalvanometerTheamplifyingcircuitofgalvanometertakestheinstrumentamplifierAD620asthecoreelement,asshowninFigure5.ThedifferentialsignaloutputbytheDCbridgeisinputfromthesocketJ1,passesthroughtheanti-radiofrequencyinterferencelow-passfiltercircuit[2]formedbyR1,R2,C1,C2,C3,andreachestheinstrumentationamplifierAD620afterweakeningtheinterferencesignal.D1,D2andR1,R2togetherformtheinputprotectioncircuitofthegalvanometer,whichcanwithstandinputvoltagesoftensofvolts.R3,R4providealoopfortheinputbiascurrentofAD620[1]toensurethatitcanworkstablyandreliably.TheresistanceR0andpotentiometerRP1betweenpin1andpin8ofAD620aregainadjustmentresistors,denotedasRG.R0isconnectedinserieswithRP1tolimittheupperlimitofthemagnificationto495times.ThepotentiometerRP2andR5,R6formthezeroadjustmentcircuitofthegalvanometertogether,realizezeroadjustmentbychangingthevoltageoftheREFpinofAD620.R7andC7formtheoutputlow-passfilterofAD620.R7,D3,D4constitutetheprotectioncircuitofthepointermeterhead.Figure5TheamplifyingcircuitofgalvanometerThemaximumsensitivityofagalvanometerisusually10uV/degreeto15uV/degree,whichcanwellmeettherequirementsoftheexperiment.TheinternalresistanceRgofthegalvanometermeterheadis4.7k,thegainadjustmentresistanceRG=R0+RP1,takeR0=100,R7=1k,whenRP1is0,theamplificationfactorofAD620isTakingintoaccountthepartialpressureofR7andtheinternalresistanceRgofthemeter,themagnificationofthegalvanometerisThecurrentsensitivityofthemeterheadis1Aminute/degree,sothevoltagesensitivityofthemeterheadis4700Vminute/degree.ThesensitivityofthegalvanometerisS=4700/G=115V/divisionMeettherequirementsofphysicalexperiments.2.5PowerMonitoringandPowerManagementCircuitofGalvanometerFigure6isthepowermonitoringandpowermanagementcircuitofthegalvanometer.TheGP2pinofthemicrocontrollerPIC10F206isconnectedwiththeP-channelMOSFETtubeQ1,thepurposeistocontrolwhethertosupplypowertotheamplifyingcircuitofthegalvanometer.WhenGP2outputislowlevel,Q1isturnedon,andthesystemsuppliespowertotheamplifiercircuit.TheroleofICL7660inpowerconversionhereistoconvert+VSto-VS.R8,R9andtheanalogcomparatorinsidePIC10F206togetherformthepowersupplyvoltagemonitoringcircuit.ThenegativeinputterminalCINoftheanalogcomparatorisconnectedtotheinternalreferencevoltageofthesingle-chipmicrocomputer(thenominalvalueofthevoltageis06V),andthepositiveinputterminalCIN+isconnectedwiththepartialpressureofR8andR9.BecausethelowestoperatingvoltageofAD620is23V,fromaconservativepointofview,thelowerlimitoftheoperatingvoltageissetto2.5V.Whenthepositivepowersupplyvoltageislessthan2.5V,thevoltageofCIN+islessthan0.6V,andthecomparatoroutputisreversed.Afterthemirocontrollerdetectsthisevent,theGP2outputshighlevel,turnsoffthepowersupplyoftheamplifiercircuit,andthenexecutestheSLEEPinstructiontomakethemicrocontrollerentersleepstatus.Figure6PowermonitoringandpowermanagementcircuitofgalvanometerInordertosavepowerconsumption,whentheworkingvoltageisnormal,thegalvanometershouldenterthesleepstate(iesoftshutdown)afterworkingforaperiodoftime,anditcanbeawakenedatanytimewhenitneedstowork.ButtonS1issetforthisfunction.Theworkingtimeofthegalvanometerispresetto15minutes.Whentheworkingtimeisup,theGP2ofthesingle-chipmicrocomputeroutputsahighlevel,shutsoffthepowersupplyoftheamplifyingcircuit,andthenexecutestheSLEEPinstructiontomakethemicrocontrollerenterssleepstate.Inthesleepstate,ifS1ispressed,thepinlevelofGP3willchange.Thiseventwillresetthemicrocontroller(note:PIC10F206hasnoconventionalinterruptfunction)andwakeupthemicrocontroller.Inthesleepstate,thecurrentconsumptionofthegalvanometerislessthan0.1A,whichisverypower-saving,sothereisnoneedtoworryaboutforgettingtoturnoffthepowersupplyofthegalvanometerandconsumingthebattery.III.SoftwareSystemWhenthegalvanometerispoweredon,themicrocontrollerfirstperformssysteminitialization,thensuppliespowertoICL7660andAD620,andthenturnsontheanalogcomparatortocheckwhetherthesupplyvoltageisappropriate.Ifthevoltageisappropriate,continuetosupplypowertotheamplifiercircuit,andthenexecutea15-minutecountdown.IfS1ispressedduringthisperiod,thetimingtimeisresetto15minutes.Whenthe15-minutecountdownisup,thesingle-chipmicrocomputerturnsoffthepowersupplyoftheamplifiercircuit,andthenentersthesleepstate(ie,softshutdown).TheflowchartoftheprocedureisshownasinFig.7.Figure7FlowchartoftheprocedureIV.ConclusionThisarticlediscussesthegalvanometerbasedoninstrumentationamplifierAD620andmicrocontrollerPIC10F206,whichhasstableperformanceandlowpowerconsumption.Thecurrentisabout4mAduringnormaloperation,andthecurrentconsumedinsleepmodeislessthan0.1uA,whichisverysuitableforbatterypowersupply.TheuseoftwoAAbatteriesforpowersupplysavesbatterycost.Thesoftshutdownfunctioncaneffectivelypreventbatteryconsumptioncausedbyforgettingtoturnoffthepower.FAQWhatisAD620?AD620isalow-cost,high-precisioninstrumentationamplifier.Itonlyrequiresanexternalresistortosetthegain.Thegainrangeis1to10,000.CanIchangeAD620toAD623whenmakingMCUproducts?BothAD620andAD623aresingleinstrumentationamplifiers,andthepinarrangementisexactlythesame.Themaindifferenceis:AD620mustusepositiveandnegativepowersupplies,AD623canbeapositiveandnegativepowersupplyorasinglepowersupply.IftheoriginalboardisAD620,youcanreplaceitwith623;iftheoriginalboardisAD623,youmaynotbeabletoreplaceitwith620(itdependsonwhetherthepowersupplyoftheoriginalboardcircuitisdualpowersupplyorsinglepowersupply).AfterreplacingAD620andAD623insingle-chipproducts,theprogramcanworknormallywithoutmodification.WhatisthedifferencebetweenAD620BRandAD620AN?Theirpackagesaredifferent.WhatistheoutputresistanceofAD620?Howtoadjustit?AD620isakindoflowpowerconsumptioninstrumentamplifier,itsoutputresistanceisabout10K,thisistheinherentcharacteristicofthischip,generallyitisdifficulttoadjust.Ifyouhaverequirementsforoutputresistance,youcangenerallyuseanexternalcircuittosolveit.IsAD620apositivephaseamplificationorareversephaseamplification?AD620isaninstrumentamplifier,theoutputvoltageis[(Vin+)-(Vin-)]*gain.Ifthedesiredsignalis(Vin+)-(Vin-),thegainispositive,whichisequivalenttopositiveamplification.Conversely,ifthedesiredsignalis(Vin-)-(Vin+),thegainisequivalenttonegative,whichisequivalenttoreverseamplification.Whatisaninstrumentationamplifier?Instrumentationamplifier,animprovementofthedifferentialamplifier,hasaninputbuffer,doesnotrequireinputimpedancematching,sothattheamplifierissuitableformeasurementandelectronicinstrumentsIDescriptionTheperformanceandstructureofthesteppermotordriverchipL297/L298areanalyzed.Atthesametime,combinedwiththeAT89C52single-chipmicrocomputer,asimplemethodofdrivingasteppermotorisintroduced.Thisbloggivesthecontrolschematicdiagram.Theactualmeasurementshowsthatthesteppingmotordrivesystemdesignedbythismethodhasthecharacteristicsofsimplehardwarestructure,easysoftwareprogrammingandlowprice.CatalogIDescriptionIIIntroductionIIIWorkingprincipleVIHardwareVSoftwareCompositionVIConclusionOrdering&QuantityIIIntroductionWhatisasteppingmotor?Asteppingmotorisaprecisionactuatorthatconvertselectricalpulsesignalsintoangulardisplacementorlineardisplacement.Thesteppingmotorhasthecharacteristicsofconvenientcontrolandsmallsize.Therefore,itiswidelyusedinnumericalcontrolsystems,automaticproductionlines,automaticinstruments,plotters,andcomputerperipherals.L297andL298caneasilyformasteppingmotordriver,andcombinedwithAT89C52single-chipmicrocomputerforcontrol.Thatis,itispossibletoformasteppermotordrivecircuitwithgoodperformanceatarelativelycheapprice.IIIWorkingprincipleSinceasteppermotorisanactuatorthatconvertselectricalpulsesignalsintolinearorangulardisplacement,itcannotbedirectlyconnectedtoACandDCpowersupplies.Instead,aspecialdevice,asteppingmotor,mustbeusedtocontrolthedriver.AtypicalsteppingmotorcontrolsystemisshowninFigure1.Thecontrollercansendoutpulsesignalswhosepulsefrequencycanbecontinuouslychangedfromafewhertztotensofkilohertz.Itprovidesapulsetrainfortheringdistributor.Themainfunctionoftheringdistributoristodistributethepulsesequencefromthecontrollinkaccordingtoacertainrule.Thenitisamplifiedbythepoweramplifierandaddedtotheinputterminalsofthesteppingmotordrivepowersupplytodrivetherotationofthesteppingmotor.Therearetwomaincategoriesofringdistributors:Oneistousecomputersoftwaredesignmethodstoachievethefunctionsrequiredbytheringdivider,usuallycalledasoftringdivider.Theotherisaringdistributorcomposedofhardware.Usuallycalledahardringdistributor.Thepoweramplifiermainlyamplifiesthesmalleroutputsignaloftheringdistributortoachievethepurposeofdrivingthesteppermotor.Figure1.TypicalsteppermotorcontrolblockdiagramVIHardwarehesteppermotorcontrolledintheblogisafour-phaseunipolar35BY48HJ120decelerationsteppermotor.TheblockdiagramofthesteppermotorcontroldriverdesignedinthisblogisshowninFigure2.ItconsistsofAT89C52single-chipmicrocomputer,optocoupler,integratedchipsL297andL298.Figure2.BlockdiagramofsteppermotorcontroldriverThesteppermotorintroducedintheblogisafour-phaseunipolar35BY48HJ120decelerationsteppermotor.TheblockdiagramofthesteppermotorcontroldriverdesignedinthisarticleisshowninFigure2.ItiscomposedofAT89C52single-chipmicrocomputer,photoelectriccoupler,integratedchipsL297andL298.AT89C52isalow-voltage,high-performance8-bitCMOSmicrocontrollerfromATMELintheUnitedStates.Thechiphasabuilt-in8Kbytesofre-erasableFlashmemory,256bytesofRAM,three16-bittimers,andaprogrammableserialUARTchannel.Therefore,itissufficienttocompletethesimplecontrolofthesteppermotor.L297isasteppingmotorcontroller(includingringdistributor).L298isadoubleHbridgedriver.Theinterfaceofthemicroprocessortothedouble-bridgesteppingmotorcomposedofthemisshowninFigure3.Theadvantageofthiscombinationisthatitrequiresfewcomponents.Asaresult,theassemblycostislow,thereliabilityishigh,andthespaceissmall.Andthroughsoftwaredevelopment,theburdenofmicrocomputerscanbesimplifiedandreduced.Inaddition,L297andL298areindependentchips,sotheapplicationisveryflexible.TheL297chipisahardwareloopintegratedchipthatcangeneratefour-phasedrivesignalsforcomputer-controlledtwo-phasebipolarorfour-phaseunipolarsteppermotors.TheheartoftheL297isasetofdecodersthatcangeneratevariousrequiredphasesequences.Thispartiscontrolledbytwoinputmodes,directioncontrol(CW/CCW)andHALF/FULL,andsteppingclockCLOCK.Itadvancesthedecoderfromonesteptoanother.Thedecoderhasfouroutputpointsconnectedtotheoutputlogicsectiontoprovidethephasesequencerequiredbythesuppressionandchoppingfunctions.Therefore,L297cangeneratethree-phasesequencesignals,correspondingtothreedifferentworkingmodes:thehalf-stepmode(HALFSTEP).Basicstep(FULLSTEP,fullstep)one-phaseexcitationmethod.Basicsteptwo-phaseexcitationmethod.Insidethepulse,thedistributorisa3bitreversiblecounter,plussomecombinationallogictogenerate8stepsofGraycodetimingsignalpercycle.Thisisthetimingsignalofthehalf-stepworkingmode.Atthistime,theHALF/FULLsignalishigh.IfHALF/FULLissettoalowlevel,thebasicstepworkingmodeisobtained,thatis,thedoublefour-beatfull-stepworkingmode.Figure3.L297PictureAnotherimportantcomponentofL297isthetwoPWMchopperstocontrolthephasewindingcurrentstoachieveconstantcurrentchoppingcontroltoobtaingoodtorque-frequencycharacteristics.Eachchopperconsistsofacomparator,anRSflip-flopandanexternalsamplingresistor.Acommonoscillatorisalsoprovidedtoprovidetriggerpulsesignalstothetwochoppers.InFigure5,thefrequencyfisdeterminedbytheexternal16-pinRCnetwork.WhenR10k,f=1/0.69RC.Whentheclockoscillatorpulsesetsthetriggerto1,themotorwindingphasecurrentrises.WhenthevoltageonRsofthesamplingresistorrisestothereferencevoltageUref,thecomparatorflipstoresettheflip-flop,thepowertransistoristurnedoff,andthecurrentdrops,waitingforthearrivalofthenextoscillationpulse.Inthisway,theoutputofthetriggerisaconstantfrequencyPWMsignal,whichmodulatestheoutputsignalofL297,andthepeakvalueofthewindingphasecurrentisdeterminedbyUref.TheinputoftheCONTROLterminalofL297determinesthatthechopperactsonthephaselinesA,B,C,DorthesuppressionlinesINH1andINH2.WhenCONTROLishigh,ithascontroleffectonA,B,C,D;Whenitislowlevel,itcontrolsINH1andINH2,sothatthesteeringandtorqueofthemotorcanbecontrolled.TheL298chipisahigh-voltage,high-currentdualfull-bridgedriver.L298isdesignedtoacceptstandardTTLlogiclevelsignalsanddriveinductiveloads.Forexample,relays,cylindricalcoils,DCmotorsandsteppingmotors.Ithastwosuppressinputstomakethedeviceimmunetotheinputsignal.Theemittersofthetriodesofeachbridgeareconnectedtogether,andthecorrespondingexternalterminalscanbeusedtoconnectperipheralsensingresistors.Anotherinputpowersupplycanbeinstalledtoenablethelogictoworkunderlowvoltage.TheL298chipisanintegratedchipinamulti-wattin-linepackagewith15leads.Figure4.L298PictureInFigure5,AT89C52isconnectedtothemicrocomputerthroughtheserialportafterMAX232levelconversion,andacceptsinstructionsfromthehostcomputer.Thensendclocksignal,positiveandnegativesignal,resetsignalandenablecontrolsignaltoL297.Inthecircuit,resistorsR13andR15areusedtoadjustthereferencevoltageofthechoppercircuit.Thisvoltagewillbecomparedwiththemagnitudeofthepotentialfedbackthroughthepins13,14todeterminewhethertoperformchoppingcontrol.Inordertoachievethepurposeofcontrollingthepeakvalueofthemotorwindingcurrentandprotectingthesteppermotor.BecauseL297hasachoppingconstantcurrentcircuitinside,thepeakvalueofthewindingphasecurrentisdeterminedbyUref.WhentwopiecesofL297areusedtodrivethetwowindingsofthesteppingmotorthroughL298,andtheUrefofeachphasewindingischangedthroughtwoD/Aconverters,thesteppingmotorsubdivisiondrivingcircuitisformed.Inaddition,inordertoeffectivelysuppresselectromagneticinterferenceandimprovethereliabilityofthesystem,anisolationcircuitcomposedoftwo16-pinphotoelectriccouplingdevicesTLP521-4isusedinthesingle-chipandsteppingmotordrivecircuit.AsshowninFigure5.Figure5.SchematicdiagramofsteppermotorcontroldriverItsfunctionistocutoffthedirectelectricalconnectionbetweenthemicrocontrollerandthesteppingmotordrivecircuit.Inthisway,theseparateconnectionofthesingle-chipmicrocomputerandthedrivingcircuitsystemgroundisrealized,andtheinterferencesignalgeneratedbythedrivingcircuitworkingunderthehigh-currentinductiveloadandtheinterferencesignalgeneratedbythesuddenchangeofthegridloadisseriallyconnectedtothesingle-chipmicrocomputerthroughtheline,whichaffectsthenormaloperationofthesingle-chipmicrocomputer.VSoftwareCompositionInthiscircuit,setP1.0portasthemotorstartbutton.P1.1,P1.2,P1.3arespeedselectionbuttons,thespeedisfromlowtohigh.P1.4isthemotorstopbutton.Themaximumspeedofthethreespeedsis500pps,1000pps,and2000pps.RXD,TXDhavebeenconnectedtotheserialportbyMAX232levelconversion.Inaddition,thestartandstopfrequencyofasteppermotorislow,generallybetween100-250Hz.Themaximumoperatingfrequencyisrequiredtobehigher,usually1-3kHz.Inordertoensurethatitwillnotlosestepduringthewholeprocessofstarting,runningandstopping,butalsocanreachthetargetpositionaccuratelyassoonaspossible,therunningspeedmusthaveanacceleration-constantspeed-decelerationprocess.Here,thecommonlyuseddiscretemethodisusedtoapproximatetheidealtrapezoidalaccelerationanddecreasecurve,asshowninFigure5.Thatis,thetimerinterruptmodeisusedtocontinuouslychangethesizeofthetimerloadvalue.Inthisexample,fortheconvenienceofcalculation,theloadingvaluerequiredforthespeedofeachdiscretepointisconvertedintotherequiredtimingtimebytheformulaandsolidifiedintheROMofthesystem.Here,TH0=(65536-time)/256,TL0=(65536-time)%256isusedtocalculatetheloadingvalue,andtimerepresentsthetimingtimerequiredforeachstep.Thesystemusesthelook-uptablemethodtofindoutthetimerequiredduringoperation,therebygreatlyreducingthetimeoccupiedbytheCPUandimprovingthecorrespondingspeedofthesystem.Therefore,theprogramismainlycomposedofcontrolmainprogram,accelerationanddecelerationsubroutine,andthemainprogramblockdiagramisshowninFigure6.Figure6.MainblockdiagramVIConclusionTheinnovationofthisblogistoproposetheapplicationofsingle-chipmicrocomputerandL297,L298integratedcircuitstoformasteppermotorcontroldriver.Ithastheadvantagesoffewercomponents,highreliability,lessspace,andlowassemblycost.IDescriptionDoyouknowtheDCregulatedpowersupply?DCregulatedpowersupplyiswidelyusedinindustrialproductionanddailylife,anditsdesignoccupiesaveryimportantpositioninpowersupplytechnology.Therefore,basedontheanalysisoftheproblemsofthetraditionalDCstabilizedpowersupply,themethodandcalculationofeachpartofthe5V,1ADCstabilizedpowersupplybasedonL7805CTaredescribed.Besides,itcanalsoprovidea5VDCpowersupplyforcounters,decoders,anddigitaltubestorealizeadditionandsubtractioncounting.ThesystemcircuitbasedonL7805CTintroducedinthisblogissimple,stable,easytocontrol,cost-effective,andisofhighuse-value.CatalogIDescriptionIIIntroductionIIIDesignrequirementsforDCstabilizedpowersupplyIVHardwareunitcircuitdesign4.1Overallstructureofthepowersupply4.2ComponentselectionVApplicationVIConclusionFAQOrdering&QuantityIIIntroductionWiththecontinuousdevelopmentofelectronictechnology,thedesignrequirementsofelectronicequipmentforpowersupplyaregettinghigherandhigher,fromtraditionalrequirementstohigh-quality,high-efficiency,andhigh-stabilitytomeettheneedsofobjects.ThenormaloperationofelectronicdevicesrequiresDCpower.DCpowersourcesincludesolarbatteries,accumulators,anddrybatteries.Butdoyouknowwhichoneisthemostcost-effective?Ofcourse,themostcost-effectivemethodistoconverttheACpowerprovidedbythegridintotherequiredDCpower.Mostelectronicequipmentusesthismode,andthethree-terminalregulatoristhemostwidelyused.AlthoughpeopleusemanytypesofDCstabilizedpowersupplieswithdifferentfunctions,theprinciplesaresimilar.ThevoltageregulatorchipusedinthesystemintroducedinthisblogisL7805CT.L7805CThastheadvantagesofsmallsize,simpleexternalwiring,stableoperationandstrongapplicability.Itcanmeetpeoplesrequirementsinlife,study,andwork.IIIDesignrequirementsforDCstabilizedpowersupplyThedesignrequirementsoftheDCregulatedsingle-channelpowersupplybasedonL7805CTareasfollows:InputACvoltage220V;OutputDCvoltage+5V;OutputDCcurrent1A;Theoutputrippleofthecircuitislessthan50mV;Theequivalentinternalresistanceislessthan0.15;Ripplecoefficientislessthan0.002%;Voltageadjustmentrate0.001%;Voltagestabilizationcoefficient0.005%.IVHardwareunitcircuitdesign4.1OverallstructureofthepowersupplyThisdesignfocusesontheknowledgeandskillsinvolvedinthemainlinksoftheDCpowersupply,andcompletesthecircuitdesignandproductionof220VACinputand5V,1ADCoutput.TheDCpowersupplyisusuallycomposedoffourlinks:PowerTransformers;Rectifiercircuit;Filtercircuit;Regulatorcircuit.AsshowninFigure1.Figure1.BlockdiagramofDCpowersupply4.1.1PowertransformerThepowertransformerconvertsthehigh-voltageACmainspowerintotheappropriatevoltageACandsendsittothesingle-phasebridgerectifiercircuit.Whenchoosingapowertransformermodel,theparametersweneedtoconsiderarecapacityandoutputvoltage.4.1.2RectifiercircuitTherectifiercircuitusestheunidirectionalconductivityofthediodetocompletetherectification.Commonlyusedrectifiercircuitsareasfollows:single-phasehalf-waverectifiercircuit,single-phasefull-waverectifiercircuitandsingle-phasebridgerectifiercircuit.Throughcomparativeresearch,inordertoovercometheshortcomingsofhalf-waverectification,theL7805CT-basedsystemusesasingle-phasebridgerectifiercircuit.Itconsistsof4diodesVD1~VD4connectedintheformofabridge.Whetheritisapositivehalf-cycleoranegativehalf-cycle,thedirectionofthecurrentflowingtotheloadRListhesame.BothtransformtheACvoltageoutputbythesecondarywindingofthepowertransformerintoapulsatingDCvoltage.Thereversevoltagethateachdevicebearsisthepeakvalueofthepowersupplyvoltage,andsymmetricalcurrentflowsthroughthepositiveandnegativehalfcyclesofthetransformer,theutilizationrateishigherthanthatofthefull-waverectifiercircuit,andthecurrentrippleisreduced.Therefore,thereisnounidirectionalmagnetization.4.1.3FiltercircuitTherectifieddirectcurrentcontainsarelativelylargealternatingcurrentcomponent,andthepulsationcoefficientisrelativelylarge,soitcannotbedirectlyusedasthepowersupplyforelectroniccircuits.FiltercircuitsarecommonlyusedtoremoveorreducetheACcomponentintheoutputvoltage,sothatpureACpowerisusedonthedevice.Thisdesignusestheenergystoragecharacteristicsofcapacitorsandinductorstosetappropriateparameters.Whenthecircuitvoltagerises,theenergystorageelementstoresenergy.Whenthevoltagedrops,theenergystorageelementreleasesenergy,soastoachievethepurposeofreducingpulsation.Thecapacityofthecapacitorisrelatedtothedischargetime.Tomakethefilteringeffectbetter,acapacitorwithalargercapacitycanbeusedasthefiltercapacitor.ThefiltercapacitorisgenerallyselectedasRLC(3~5)T/2.4.1.4VoltagestabilizingcircuitTheDCvoltageobtainedaftertheACpowerisrectifiedandfilteredoftenfluctuateswiththefluctuationofthegridvoltage,temperaturechanges,andloadresistancechanges.Then,thequalityofpowersupplywillbereduced,affectingtheoperationoftheequipment.Therefore,avoltagestabilizingcircuitneedstobeaddedbetweenthefiltercircuitandtheloadlinktoachievethepurposeofstabilizingpowersupply.ThechipL7805CThasthecharacteristicsofgoodvoltageregulationperformance,highreliability,easyinstallationandlowcost.Therefore,thelinearstabilizedpowersupplyreplacesthediscretestabilizedcircuitandiswidelyused.Inordertoreducetheinterferenceandmakethevoltagestabilizingcircuitworknormally,theinputvoltageshouldbeatleast2.5~3Vhigherthantheoutputvoltage.4.2Componentselection4.2.1SelectionofpowertransformerConsideringthediodeforwardvoltagedrop,wireresistance,andpowergridfluctuations,theoutputvoltageUIofthethree-terminalintegratedregulatorshouldmeet:Where:Uomaxisthemaximumoutputofregulatedpowersupply;(UI-UO)ministheminimumvoltagedifferencebetweentheinputandoutputoftheintegratedregulator;UIisthechangeoftheinputvoltagecausedbythefluctuationofthepowergrid(generallytakenas10%ofthesumofUO,(UI-UO)min,andUIP).Fortheintegratedthree-terminalregulator,when(UI-UO)min=2~10V,ithasbettervoltageregulationcharacteristics.WhenU1=10VWhenU2=9VInasingle-phasebridgerectifiercircuit,therelationshipbetweenthetransformersecondarywindingcurrentI2andthecapacitorfilteroutputcurrentIIis:Insummary,chooseatransformerwithacapacityof15VAand9V.4.2.2SelectionofrectifierdiodeBecause,thecurrentflowingthrougheachrectifierdiodeinthebridgecircuitis:Themaximumreversepeakvoltageofeachrectifierdiodeis:Insummary,selectthetransistorIN4001,itsparametersare:ID=1A,URM=50V.4.2.3SelectionoffiltercapacitorAlthoughthecurrentpassingthroughthediodeisapulsatingcurrent,becausethecapacitorChasanenergystorageanddischargefunction,thisreducesthedegreeofvoltagepulsationacrosstheloadRLandincreasestheaveragevalue.TheaveragevalueandsmoothnessoftheDCvoltageontheloadarerelatedtothedischargetimeconstant=RLC.ThelargerthevalueofCorRL,theslowerthedischargeofC.ThelargertheoutputDCvoltagevalue,thebetterthefilteringeffect;otherwise,theworse.Generallytake:TheACpowersupplyinsomeAsiancountriesisa50Hzsinewave,with50identicalwaveformspersecond.Afterfull-waverectification,boththepositiveandnegativehalfwavesbecomepulsatingdirectcurrentinthesamedirection.Atthistime,thereare100identicalwaveformspersecond,thatis,f=100Hz.Sothefiltercapacitorcapacityis:amongthem,TheoutputDCvoltageofthecapacitorfiltercircuitisestimatedas:Insummary,twoelectrolyticcapacitorsof2200Fand50Vcanbeused,andtheyareconnectedinparallel.Inordertofilterouttheinterferenceofhigh-frequencysignalsandimprovethedynamiccharacteristicsofthepowersupply,a105pF,50Vhigh-frequencyceramiccapacitorisconnectedinparallelatbothendsofthefiltercapacitor.4.2.4Howtochooseathree-terminalintegratedvoltageregulatorTheconditionthatthepowerconsumptionofthethree-terminalintegratedvoltageregulatormustmeetisgreaterthan5Wandtheoutputvoltageis5V.ThisdesignchoosesL7805CT,theoutputvoltageis4.8~5.2V,thequiescentcurrentis4.2~8mA,andthemaximumoutputcurrentcanbe1.5A,whichmeetsthedesignrequirements.Consideringthelargeoutputcurrent,aheatsinkneedstobeadded.VApplicationAdoptthedesignbasedonL7805CTtoprovide5VDCpowersupplyforcounter,decoderanddigitaltube.Usethebuttontogenerateasingleclock,realizethecountofmodulo10throughthestandardcountercircuit,andgeneratethecorrespondingcode.Thevalueisoutputtotheintegrateddecodingcircuitthroughthedecodertodisplaythenumbers0-9.UsetheDPsectionoftheintegrateddecodingcircuitasapower-onindication.Thecounterhasaresetbutton,andtheintegrateddecodingcircuitadoptsacommoncathodestructuretorealizeadditionandsubtractioncounting.asshowninfigure2.Figure2.L7805CircuitVIConclusionThe5V,1ADCpowersupplydesignbasedontheL7805CTdescribedinthisblogcanprovide5VDCpowersupplyforcounters,decoders,anddigitaltubestoachieveadditionandsubtractioncounting.ThedesigncircuitoftheL7805CTissimple,withfewcomponents,lowpowerconsumptionandstable.Therefore,itcanbeextendedtootherobjectapplicationsasaDCstabilizedpowersupplytoprovideelectricalenergy.FAQWhatisl7805?AvoltageregulatorICmaintainstheoutputvoltageataconstantvalue.7805IC,amemberof78xxseriesoffixedlinearvoltageregulatorsusedtomaintainsuchfluctuations,isapopularvoltageregulatorintegratedcircuit(IC)....7805ICprovides+5voltsregulatedpowersupplywithprovisionstoaddaheatsink.WhatistheworkingprincipleofIC7805?AvoltageregulatorICmaintainstheoutputvoltageataconstantvalue.7805IC,amemberof78xxseriesoffixedlinearvoltageregulatorsusedtomaintainsuchfluctuations,isapopularvoltageregulatorintegratedcircuit(IC).Thexxin78xxindicatestheoutputvoltageitprovides.HowdoItesta7805withamultimeter?TurnontheDCpowersupplyandadjusttheoutputvoltageofabout8Vorslightlylarger.Oralternativelyyoucanuseabattery9V-12Vasvoltagesource.Lookatthevoltmeterpanelwhenyousetthevoltage.PrepareaDCvoltmeterreadingsonvoltagerange50VtomeasuretheoutputvoltageoftheIC7805.Howdoes7805regulatevoltage?For7805IC,itis+5VDCregulatedpowersupply.ThisregulatorICalsoaddsaprovisionforaheatsink.Theinputvoltagetothisvoltageregulatorcanbeupto35V,andthisICcangiveaconstant5Vforanyvalueofinputlessthanorequalto35Vwhichisthethresholdlimit.

LOG14

I.74HC164Introduction74HC164adoptsDIP-14,SO-14,SSOP-14andTSSOP-14packagepinconfiguration.ItiscomplementarytoMOS8-bitserialinputandparalleloutputunidirectionalshiftregister,thelogicsymbolisshowninthefigure1.Thepowersupplyvoltageis2~6V.Inthefigure1,AandBaretheserialcodeinputterminals;CLRistheclearinputterminal;CLKistheclockpulseinputterminal.Withthearrivaloftherisingedgeoftheclockpulse,thestateofphaseA,phaseBandthesubsequentphaseshiftsfromQAtoQHinturn.CatalogI.74HC164IntroductionII.74HC164LogicSymbolIII.CircuitDesignIV.HowtoCheckandRepairtheCircuitFAQOrdering&QuantityII.74HC164LogicSymbolFigure174HC164LogicSymbolIII.CircuitDesignFigure2isaninstrumentcircuitcomposedofserialinputandparalleloutputdigitalintegratedcircuits.T2-T5,C5andresistancetogetherformaturnsignalflashingoscillationcircuit.WhentheDR(connectedtotheturnswitch)inJ8isdisconnected,thiscircuitwillnotworkandtheturnsignalwillnotflash;whenDRison,theoscillationcircuitstarttowork,theturnsignalstartstoflash.Figure2MetercircuitdiagramDRisathree-positionswitch,onepoleisconnectedtotheleftturnsignal,onepoleisconnectedtotherightturnsignal,onepoleissuspendedintheair,andtheotherendofthepolehitstheground.Theswitch-offcircuitiscomposedofTl,DLRllandR12.Aswitch-typeHallelementisinstalledinthefrontandrearbrakesoftheelectricbicycle.Whentheswitchisswitched,theHallelementoutputsalowpotential,thatis,theBRKterminalintheplugJ2isgrounded,Tlisturnedon,andthereisavoltageofnearly5VonthecollectorofTl.ThisvoltageissenttothecontrollerthroughtheBRKterminalinJ2,andthepowersupplycircuitofthemotoristurnedoff.Themotorstopsworkingandactsasabrake.Onthecontrary,whenthebrakeisnotpinched,theHallelementoutputsahighpotential,Tliscutoff,andthemotorrunsnormally.Because74HC164isan8-bitserialinputandparalleloutputshiftregister,itformsamovementmodeandbatterypowerdisplaycircuitwithlight-emittingdiodes.74HC164soutputpin13,pin11,andD5-D7formthesideofthesportsmodedisplaycircuit,andpins6and10andD8-D12formthebatterypowerdisplaycircuit.Thedisplaysignalfromthecontrollerissenttotheserialinputterminals1and2ofthe74HC164throughtheDATAterminalintheJ2,andthenshiftedbytheinternalcircuit,thedrivingsignalisoutputfromtherelevantoutputterminaltolightupthecorrespondinglight-emittingdiode,soastocompletethecontrolofthedisplaycircuit.IV.HowtoCheckandRepairtheCircuitThiscircuitisrelativelysimpleandeasytorepair.Themainbasisforrepairingistojudgethequalityof74HC164.First,checkwhetherthe+5Vvoltageisnormal,andthencheckwhetherthevoltageatpin③ofthe74HC164sclocksignalinputiscloseto+5V.Ifitislowerthan+5V,andafterdisconnectingR73,theCLKterminalvoltageofJ2isnormal,andthe74HC164isdamaged.IfthevoltageoftheCLKportisabnormal,thefaultisinthecontroller.Next,measurewhetherthevoltageoftheserialinputterminals①and②changesduringthetransitionofthemotionmode.Ifnot,thefaultisinthecontroller;ifthereis,the74HC164isdamaged.Fromtheactualrepairsituation,mostofthe74HC164failuresarecausedbydamagetotheinternalcircuitofthe⑩pin(powersupplyterminal).Inaddition,whenpurchasing74HC164,youcanfirstmeasuretheresistanceofthe⑩pin.Theresistancevalueshouldbeabout4kDinthepositivetestandinfiniteinthereversetest.FAQHowdoesthe74HC164transmitdatainthemicrocontrollercircuit?Onepinofthesingle-chipmicrocomputerislikeafaucet,andthedataissentonebyone,thatis,likethewaterfromthefaucet,drippingdropbydrop.The74H164islikeasmallbowlreceivingwater.Itisjustfullafterreceiving8dropsofwater.Atthistime,itissenttothedigitaltube.Thesingle-chipmicrocomputermustsendan8-bit(ormore)data,ifitissentatthesametime,itisaparalleltransmission,ifitisabitbybit,itisaserialtransmission.Thedataofthesingle-chipmicrocomputerissenttothe74HC164bitbybit,whichisserial,andthe74HC164sendsthedatatothedigitaltubeatonce,whichisparallel.So74HC164playsarolefromserialtransmissiontoparalleltransmission.Whatisthedifferencebetween74HC164Dand74HC164NMCU?TheDin74HC164Drepresentsachippackage.TheNin74HC164Nmeansdualin-lineplasticpackaging.Whatisthedifferencebetween74HC164and74LS164,cantheybeusedtogether?74ls164isaTTLcircuit,thepowersupplyvoltageis5V,thehigh-leveloutputcurrentIohis-0.4MA,andthelow-leveloutputcurrentis8MA.74HC164isaCMOScircuit,thepowersupplyvoltageis2V~6V,theoutputdrivecurrentcanreachplusorminus20MA.Ifthepowersupplyvoltageyouuseis5Vandtheoutputdrivecurrentissuitablefor74ls164,theycanbeusedtogether.Whatdevicescan74hc164bereplacedwith?74HC164isaCMOSdevicewithapowersupplyvoltageof2V-6V.Itcanbedirectlyreplacedby74HCT164,40H164.Ifthepowersupplyvoltageis5Vandtheoutputdrivecurrentissmall,itcanalsobereplacedby74164,74LS164,74F164,74ALS164.Whichof74LS164and74HC164hashigherdrivingcapability?74LS164isaTTLdevicewithahigh-leveldrivingcapabilityofabout0.4mAandalow-leveldrivingcapabilityofabout8mA.74HC164isaCMOSdevice,withhigh-levelandlow-leveldrivecapabilityupto20mA.TheabovedatacomesfromDATASHEET.Butgenerallyspeaking,thehigh-leveloutputcapabilityofmanyCMOSdevicesisweak,smallerthanTTL,andthelow-leveldrivecapabilityisstronger.Can74hc164nbeusedtodrivethedigitaltube?Ofcourse,youcanusethe164chiptodrivethenixietube,whichismostlyusedinsituationswheretheIOportresourcesaretightandthedisplaydatarefreshofthenixietubeisslow.Whendesigningthecircuit,multiple164chipsareusedincascade,nomatterhowmanydigitaltubesaredriven,only2IOportsofthesingle-chipmicrocomputerareoccupied.ItcanbesaidthatitisthemostIOport-savingdrivingmethod,anditisstilldrivenstatically,withoutstrobeandbrightnessLowphenomenon.Thedisadvantageisthatmultiple164sareusedincascadeconnection,whichwillcausethesingle-chipmicrocomputertosendalargeamountofdisplaydata(1bytepernixietube)atonetimewhenrefreshingthedisplaydata.Duringthisprocess,thenixietubewillbeallon,althoughthedataissentTheprocessdurationisveryshort,butitstillaffectsthedisplayeffect.Itisrecommendedtoturnoffthedigitaltubewhenrefreshingthedata.I.DescriptionAutomaticgaintechnology(AGC)iswidelyusedinthefieldofindustrialautomationclosed-loopcontrol.Inindustrialcontrol,time-varyinggainamplifiersareoftenneededtomeetproductionneeds,ormadeithasacertainregularitytoensurethestabilityofthecontroloutputamplitude,therebyreducingtheinterferenceoftheinputinterferencenoisesignal.Forthesystemtoadjustquikly,thispaperdesignsanAGCcontrollerbasedonthecombinationofAGCchipAD603andswitchingpowersupplychipMC34063,cleverlyusingMC34063sstablereferencevoltageanddynamicvoltageadjustmentoutputtoaccessAD603gaincontrolterminaltocontroltheamplificationgain,thereforeachievethegoalofconstantsystemoutputamplitude.AD603CatalogI.DescriptionII.WorkingPrincipleoftheSystemIII.AD603IV.MC34063V.SystemHardwareCircuitDiagram5.1InputBufferAttenuationCircuit5.2AD603AutomaticGainAmplifier5.3OutputAmplitudeDetector5.4MC34063FeedbackCircuitVI.SystemOperationResultsVII.ConclusionFAQOrdering&QuantityII.WorkingPrincipleoftheSystemThesystemusesAD603asthecorecontroldevice,supplementedbytheswitchingpowersupplychipMC34063tocollecttheoutputofthecontroller,theoutputvoltageistransferredtothevoltagecontrolterminalofAD603throughMC34063tochangetheamplificationgain.ThesystemworkingprincipleblockdiagramisshownasinFig.1.Figure1SystemBlockdiagramInthisclosed-loopcontrolsystem,theMC34063circuitisusedasitsfeedbacklinktodynamicallycollecttheamplitudeoftheoutputsignalofthesystem,andcontroltheamplificationgainofAD603byadjustingthedutycycleoutputvoltageoftheinternalsignal.Thefeedbacklinkinthefigurecanbereplacedwithamicroprocessor.ThemicroprocessorcollectstheoutputvoltageamplitudethroughA/D,transfersittothemicroprocessorchipforsignalprocessing,andthenfeedsbacktotheinputoftheentiresystemthroughD/Aoutputcontrolvoltage.However,thismethodistoocomplicated,becausetheriseandfallofthedigitalchiptakealongtimetosetup,whichaffectstheresponsespeedoftheentiresystem,andrequiresrelativelyhighsignalprocessingalgorithms.Theswitchingpowersupplychipwidelyusedinpowersupplytechnologyisdynamicallyadjustedtoimproveitsoperatingspeed.Inaddition,itsdevelopmentcostislow,whichisconducivetothepromotionoftheindustrialcontrolfield.III.AD603AD603isachipwithprogrammablegain,lownoise,ithas3workingmodes,correspondingtodifferentgainranges.Inordertomakethecontrolmoreextensive,themaximumbandwidthmodeisselectedas90MHz.Thegainisexpressedindecibels,theamplificationgainiscontrolledbythecontrolvoltagetoalinearrelationshipof25mV/dB,andtheslewrateis275V/s.Thegaincontrolvoltageneedstobeinputduringnormaloperation.Thegainformulais:Intheformula:Gisthegain,dB;G0isthestartingpointofthegain,andthesizeofG0isdeterminedbythepinconnection.Thecircuitdesignedinthispapershort-circuitsVOUTandFDBK,G0=10dBisthewidebandmode(90MHzwideband),thegainrangeGofAD603is-11.09~+31.05dB,andVGisinthelinearrangewhentherangeis-500~500mV.ThegaincontrolvoltageVGiscontrolledbytheMC34063output.AD603inputsignalamplitudeUINP1.4V,theactualindustrialcontrolfieldofteninputplusinterferencesumisgreaterthan1.4V,ifthissignalisdirectlyaddedtothesystem,thedistortionislargeandlong-timeworkwilldamagetheAD603,soyoumustaddaninputbufferandattenuationcircuit.IV.MC34063MC34063isamonolithicbipolarintegratedcircuitusedinthefieldofDC-DCconvertercontrol.Itischeapandwidelyusedinthefieldofswitchingpowersupplies.Itcanuseaminimumofexternalcomponentstoachieveswitchingboostandbuck.Itsoperatingfrequencyis0.1-100kHz.ThetraditionalAGCcontrollerconstitutesaclosed-loopcontrolsystem,whichgenerallyneedstoperformA/Dsamplingontheoutputofthesystem,andthentransferthedatatothesingle-chiporcomputerforalgorithmdataprocessing,andjudgetheexecutionsignalD/Aoutputtomaketheactuatorexecute.Inthisfeedbackprocess,sampling,algorithmprocessingandexecutionobviouslyconsumetoomuchtime,andforsomecomplexcontrolsignals,algorithmdataprocessingrequirementsarehigh,andspecialDSPchipsarerequired,whichiscostly.Therefore,theuseofasingleanalogelectroniccircuittoachieveaclosed-loopcontrolsystemhashigherefficiencyandlowercost.InspiredbytheworkingmodeoftheMC34063step-downcircuit,itisanewdesignideatorealizethechangeoftheAD603gaincontrolvoltagebyusingthecharacteristicsoftheMC34063todynamicallyadjusttheoutputvoltage.Theexperimentalverificationisfeasibleanditissimplerandfasterthantheprogramcontrolmethod.Figure2showstheMC34063step-downcircuit.Figure2MC34063step-downcircuitAsshowninFigure2,theinputis+12V,theoutputis+5V,thereferencevoltageofpin5togroundis+1.25V,theresistanceofpin5togroundisR1=1.2k,andtheoutputandpin5areconnectedtoR2=3.6k,Accordingtotheresistancedividerratio,theoutputisclampedat+5V,thusachievingaregulatedoutput.AppliedinthefieldofAGCcontrol,youcanconnecttheoutputofMC34063tothecontrollergaincontrolterminal,andtheinputtotheoutputterminalofthecontroller.Accordingtoitsworkingprinciple,MC34063collectstheoutputoftheAGCcontrollerandtransmitsittopin5.ItsinternaldynamicallyadjuststhePWMdutycycle,dynamicallychangestheAD603gaincontrolvoltage,andcanavoidtheinterferenceofthesystem,andrealizethefunctionsimilartothePIDalgorithm.Itreplacesthealgorithmicdataprocessingmechanism,whichissimpleandeffective,andhascertainreferencesignificancetothefieldofindustrialautomationcontrol.V.SystemHardwareCircuitDiagramFigure3isthesystemhardwarecircuitdiagram.Thesystemismainlydividedintoinputbufferattenuationcircuit,AD603automaticgainamplifier,outputamplitudedetectorandMC34063feedbackcircuit.Figure3SystemHardwarecircuitdiagram5.1InputBufferAttenuationCircuitBecausetheAD603inputsignalamplitudeVINPislessthanorequalto1.4V,fourdiodeclampsareused.Accordingtotheunidirectionalconductivityofthediodeandtheforwardconductionvoltagedropofsilicon,theinputcharacteristicsarelimitedtomeettherequirementsofAD603.Theinputvoltagerequirements,thefollowerplaystheroleofisolatingthechip.AsshowninFigure3,part①.5.2AD603AutomaticGainAmplifierThe3pinofAD603isthesignalinputterminal,the2and4pinsareconnectedtothegroundwithR4=0,R5=0resistancetomakeitworkmorestable.The5and7pinsareconnectedtotheoutput,whichisthesystemoutputoftheAGCcontroller.Pin1isthegaincontrolvoltageVGterminal,thiscontrolvoltageisconnectedtotheoutputterminalofMC34063,MC34063generatesthecorrespondinggaincontrolvoltageVGaccordingtotheoutputofthesystem.5.3OutputAmplitudeDetectorInthefieldofindustrialcontrol,thesignalisonlyintheformofDC,andtheACsignalalsooccupiesacertainproportion.ForthecontroloftheDCsignal,thesystemoutputcanbedirectlytransmittedtotheMC34063forprocessing,buttheamplitudeoftheACsignalmustbedetected,sothedesignisshowninFigure3inpart③.Commonamplitudedetectors,suchasdioderectifierbridges,areonlysuitableforsituationswheretheinputvoltageisfargreaterthanthediodeconductionvoltagedrop.InAGCcontrol,thesignalinthesystemisoftenlowvoltage,soitcannotbeused,soitisverynecessarytodesignanamplitudedetectorthatcanavoiddiodeconductionvoltagedrop.AfterRCcharging,theDCvoltagevaluewithacertainrelationshipisobtained.InFigure3,thevoltageattheintermediatenodeofR13andR14isUf,andtheexpressionis:Intheformula,UINPistheinputamplitude,V.5.4MC34063FeedbackCircuitTheintermediatenodevoltageUfofR13andR14isproperlycalculatedbyasame-invertingamplifierandanadder,andthenconnectedtopin5ofMC34063.Atthistime,itisclampedat5V,andUf=1Vwhenreversed,thentheAGCcontrollersystemcanbedynamicallymaintainedstabilityofoutputvoltageamplitude.Whenthesysteminputisunstableorthereisnoiseinterference,MC34063dynamicallychangestheoutputvoltagevalueaccordingtotheamplitudedetectionresult,soastoachievethepurposeofchangingthegaincontrolvoltageVG.AsshowninthelowerpartofFigure3,theoutputvoltageofpin2ischargedanddischargedthroughswitchingandspecificSchottkydiodes,andtheattenuatedpartialvoltageistransmittedtopin1ofAD603,whichrealizestheautomaticadjustmentoftheamplificationgainandsuccessfullyrealizestheswitchingpowersupplytechnologyapplicationinthefieldofautomaticcontrolgain.VI.SystemOperationResultsTheexperimentalsettingisthatifthesysteminputsaDCsignal,theoutputwillbeaconstant+1VDC;ifanACsignalisinput,theoutputwillbeanACsignalwithaconstantamplitudeof+1V.Intheexperiment,twoinputmethodsweretestedandverified,andbothmetthedesignrequirements.Table1ispartoftheexperimentaldataoftheinputDCsignal.Intheexperiment,theinputoftheAGCcontrollerisconnectedtothevoltageregulatorsource,andtheinputvoltageiscontinuouslyadjusted.Table2ispartoftheexperimentaldataoftheinputACsignal.Intheexperiment,theAGCcontrollerinputisconnectedtotheUTG9002Csignalgenerator,theamplitudeoftheinputsinewaveiscontinuouslyadjusted,andtheoutputisconnectedtotheoscilloscopetoobservethewaveform.Observationfoundthatnomattertheinputamplitudebecomeslargerorsmaller,theoscilloscopewaveformisbasicallyunchanged.ReadtheoscilloscopewaveformamplitudeandfillinTable2.VII.ConclusionThisarticlesummarizesthedesignoftheAGCcontrollerbasedonAD603andMC34063.ExperimentshaveverifiedthattheAGCcontrolleriseffectiveandmeetsthedesignrequirements.Anewapplicationofswitchingpowersupplychipsinthecontrolfieldisproposed.BecausetheinternalPWMdutycycleisfaster,itcanreplacethetraditionalprogrammableAGCcontroller.Amongthem,MC34063canalsobereplacedbyotherswitchingpowersupplychips.Ithastheadvantagesofuniversalapplicability,simpledesign,lowcost,andithasimportantpracticalvalue.FAQWhatisAD603?AD603isalow-noise,voltage-controlledamplifierforradiofrequency(RF)andintermediatefrequency(IF)automaticgaincontrol(AGC)systems.Itprovidesprecisepin-selectablegain,withagainrangeof-11dBto+31dBat90MHzbandwidth,andagainrangeof+9dBto+51dBat9MHzbandwidth.Anyintermediategainrangecanbeobtainedwithanexternalresistor.Thenoisespectraldensityreferredtotheinputisonly1.3nV/Hz,andthepowerconsumptionis125mWwhenusingtherecommended5Vpowersupply.WhataretheproblemsthatneedtobepaidattentiontowhenusingAD603?Thevoltagecannotbetoohigh.Generally,thevoltageisplusorminus5V,andthemaximumvoltagecannotexceedplusorminus7.5V.Theoutputvoltagecannotexceed2V.Howtosolvetheself-oscillationproblemofAD603?Forhigh-frequencyoperationalamplifiers,thefollowingpointsarethebasicwaystosolveself-excitation.Thepowersupplyisstableandnoripple.Theelectricalconnectionwiresareasshortaspossible.Thead603circuitshouldbefarawayfromthepowercircuit,especiallyawayfromthetransformer.Thepowertransformerandthecircuitboardofad603shouldbeshieldedwithametalboxandgroundedifpossible.Onepointisveryimportant.Foropamps,toolargemagnificationcaneasilycauseself-excitation,soreducethemagnificationasmuchaspossibleandminimizethenumberofmagnificationlevels(generallynotgreaterthan4).Reverseamplificationcansuppressself-excitationinmulti-stageamplification.Ifyouwanttoconnecttothepoweramplifierandthenamplify,itisbesttousetwopowersupplies,andthecircuitshouldbeconnectedtothesameground.WhatisthedifferencebetweenAD603AQandAD603AR?Theirdifferencesareinmodel,Temperature,Package.AD603AQ-40Cto+85C8-LeadCERDIPAD603AR-40Cto+85C8-LeadSOIC_NAfterinputtinganACsignalandbeingamplifiedbyAD603,whydoestheoutputcontainaDCsignal?HowtoeliminatetheDCsignal?WhentheDCblockingcapacitorisnotused,thebiasvoltageoftheinputcircuitneedstobeadjustedforcompensation.IftheDCvoltageoftheACsignalisnotfixed,onlyaDCblockingcapacitorcanbeused,ortheaveragevaluecanbeusedtoeliminateitaftersamplingthenumber.

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I.IntroductionForlargesystemssuchasmissileweaponsandequipment,theirperformanceisoftenaffectedbytheexternalenvironmentandtheirownoperatingconditions.Amongthem,theinfluenceoftemperatureoftenplaysaveryimportantrole.Therefore,temperaturedetectionandcontrolhasalwaysbeenthefocusofmanyresearchers.However,sometemperaturemeasurementandcontroldeviceshavelowaccuracyandinaccuratetemperaturecontrol,andsomenewinstrumentsareexpensiveanddifficulttopromote.Itshouldbeparticularlypointedoutthatthetemperaturemeasurementandcontrolsystemdevelopedinthepastisusuallyanindependentsystem,onethingforoneuse,itisdifficulttobeadoptedbyothersystems,andthereareproblemssuchasmaintenancedifficultiesandinconvenience.Tothisend,theauthordevelopedahigh-precisiontemperaturemeasurementandcontroldevicesuitableforresearchanddevelopmentunderlaboratoryconditionsbasedonthecurrentlypopularmodulardesignprinciple.ThedeviceusesanewintegratedtemperaturesensorAD590asthetemperaturemeasurementelement,andprovidestwocontrolunitsforexperimentalcomparison.Bymeasuringandcontrollingthetemperatureinthethermostat,satisfactoryresultshavebeenobtained.CatalogI.IntroductionII.WorkingPrincipleIII.IntegratedTemperatureSensorAD590IV.TemperatureMeasuringBridgeV.PIDRegulatorVI.ProgramDesignVII.ExperimentalAnalysisandConclusionFAQOrdering&QuantityII.WorkingPrincipleFigure1istheelectricalschematicdiagramoftheWCZ-98temperaturemeasurementandcontroldevice.Itsworkingprincipleis:thetemperaturesignaltakenbythetemperaturemeasuringbridgewithAD590asabridgearmisdifferentiallyamplifiedandbufferedandthensentallthewaytothedigitaldisplayfordigitaltemperaturedisplay,andtheotheriscomparedwiththesetvalue.ThecompareddifferenceiscontrolledbyswitchKandcanchoosetosendtotwo-wayadjustmentcontroller.Onerouteiscomposedofacomparisonamplifierandarelay,whichcanbeusedasanadjustmentcontrollertoformanindependenttemperaturemeasurementandcontrolequipmentwithoutconnectingtoacomputer;theotherrouteisaPIDregulator(composedofA/D,D/AandComputercompositionofPIDadjustmentsoftware)andSCRcomposition.Thesignalfromtheregulatingcontrollerrealizestemperaturecontrolthroughthetemperaturecontrolactuator.Figure1ElectricalschematicdiagramoftemperaturemeasurementandcontroldeviceIII.IntegratedTemperatureSensorAD590AD590isadedicatedintegratedtemperaturesensorproducedbyAmericanADcompany,whichbelongstothecurrentoutputtype.Figure2showsthecurrent-voltagecharacteristiccurveofAD590atthreedifferenttemperatures.Inacertaintemperaturerange,itisequivalenttoahighresistancecurrentsource,anditscurrenttemperaturesensitivityislA/K.Itisnotsusceptibletointerferencefromcontactresistance,leadresistance,voltagenoise,etc.Inaddition,italsohasthecharacteristicsofsmallsize,hightemperaturemeasurementaccuracy,goodlinearityandstronginterchangeability.Itisverysuitableforlong-distancemeasurementandcontrol.Itisalsosuitableforthecharacteristicsofmodularandsplitstructurerequiredbythisarticle.Themaintechnicalindicatorsare:Temperaturemeasurementrange:hCurrentoutput(calibrationfactor):lA/K;Powersupplyvoltage:DC4-30V;Linearity:lessthan0.5℃inthefullscalerange;Repeatability:0.1℃;Outputimpedance:about10MQLong-termdrift:0.1℃/monthFigure2I-VcurveofAD590ThecurrentIrflowingthroughtheAD590isasingle-valuedfunctionoftheabsolutetemperatureofitsenvironment,andthemicroampereofIrisequaltotheabsolutetemperatureT,namely:Ir=T10-6A=TA(1)IV.TemperatureMeasuringBridgeFigure3istheschematicdiagramofthetemperaturemeasurementbridge.ThevoltageformedonthecurrentIiR2andRw2flowingthroughtheAD590is:Ul=Ii(R2+Rw2)(2)Figure3SchematicdiagramoftemperaturemeasuringbridgeByadjustingRw2tomake(R2+Rw2)equalto10K,substitutingformula(1)intoformula(2),wecanget:U1=Ii(R2+Rw2)=T10-2V(3)U2=2.732VbyadjustingRwl.Thentheoutputofthebridgeis:UAB=U1﹣U2=T10-2﹣2.732=(T﹣273.2)10-2V(4)BecauseTistheabsoluteambienttemperaturemeasuredbyAD590,aftersubtracting273.2fromit,theCelsiustemperaturetcanbeobtained,namely:UAB=t10-2V(5)Atthispoint,thetemperaturemeasuringbridgeconvertstheambienttemperatureintoavoltagevaluethatisproportionaltothetemperatureinCelsius.V.PIDRegulatorOneoftheadjustmentcontrollersofthetemperaturemeasurementandcontroldeviceusesaPIDregulator(proportionalintegralderivativeregulator),whichcandeterminethesizeofthecontrolquantityaccordingtotheproportionalvalue,integralvalue,andderivativevalueofthedifferencebetweenthetemperaturesetvalueandtheactualvalue.Thetemperaturemeasurementandcontroldeviceadoptstheoutputfeedbacktypecontrol.Extractingthispartfromthegeneralprinciplediagram,youcangetthePIDcontrolprinciplediagramasshowninFigure4.Inthefigure,UdandUarethesetvalueandactualvalueofthethermostatrespectively,theerrore=Ud﹣KT,Kisthemagnificationofthemeasuringtransducer,andYistheadjustmentvalueofthePIDoutput.Figure4PIDcontrolprinciplediagramThesimulationexpressionofPIDalgorithmis:Intheformula,Y(t):regulatoroutputvalue;E(t):inputdeviation;KP:regulatorproportionalcoefficient;Tl,TD:verseunitintegral,derivativetimeAfterdiscretizingequation(6),thePIDincrementalcontrolequationisobtained:Intheformula,theintegralcoefficientKl=KPT/T1,thedifferentialcoefficientKD=KPTD/r,andTisthesamplingperiod.thenapply(7)toZ-transform,andget:Intheexperiment,theauthorusedastepsignaltoroughlymeasuretheresponseintheopen-loopstate.Fromthestepresponsecurve,itisknownthatthethermostatisafirst-orderinertialinkplusapuretimedelaylink,namely:Thelagtimerofthesystemisdeterminedtobeapproximately20seconds,andthetargettimeconstantTPisapproximately50seconds.Selectthecontroldegreetobe1.5,accordingtothestepresponsecurvetuningparametermethod(refertoliterature[1]),obtain:T=0.34z=6.8sKr=0.85Tr,/r=2.125T1=1.62r=32.4sTD=0.65r=13sSubstitutingtheabovevalueforequation(9),wecanobtain:Q0=6.41Q1=-5.96Q2=4.06TheequationofPIDregulatoris:VI.ProgramDesignThePIDcontrolprogramflowoftheWCZ-98temperaturemeasurementandcontroldeviceisshowninFigure5.ThebasicideaisthesameasthegeneralPIDcontrolflow.Itsnoneedtorepeathere.Figure5PIDcontrolprogramflowchartVII.ExperimentalAnalysisandConclusionPutthetemperaturemeasurementandcontroldeviceintoathermostatwithanexternaldimensionof248208262(mm).Thethermostatuses50mmthickpolystyreneastheheatinsulationmaterialandwaterasthemedium.Theheatingdeviceiscomposedof2SRS3-220/0.5heatingtubesandauxiliarypartstopreventleakage.Thetemperaturecanbepresetoutsidethethermostatandthereisaswitchtoselectthetypeofcontroller.Throughexperiments,comparingthecontroleffectsofthetwoadjustmentcontrolmethods,wefoundthatthetemperatureoftheadjustmentcontrollercomposedofacomparisonamplifierandarelayisnotstableduringthetemperaturecontrolprocessandalwaysfluctuateswithinacertainerrorrange.ThetemperaturecontrolperformanceoftheregulatingcontrollercomposedofPIDregulatorandthyristorisverygood.Takingtemperaturecontrolof60Casanexample,thetemperaturechangecurveobtainedbytheexperimentisshowninFigure6.Figure6PIDtemperaturecontrolexperimentresultcurveItcanbeseenthattheuseofanalogcircuitsforadjustmentandcontrolisbeneficialtomakethemeasurementandcontroldeviceanindependentinstrument(noneedtoconnecttoacomputer),anditstemperaturemeasurementandcontrolaccuracycanmeetthegeneralrequirements;andthroughPIDcontrol,itsprecisionoftemperaturemeasurementandcontrolisveryhigh.Itisusedinconjunctionwiththethermostatandtheself-developedSYZJX-2experimentaladapterbox.TheanaloginputboardPCL-818LandtheanalogoutputboardPCL-726areconnectedtothecomputertoachievehigh-precisiontemperaturecontrol.FAQWhatisAD590?AD590isatemperaturesensor,thecurrentoutputsensitivityis1A/℃,thestandardoutputvalueis298.2Aat25℃,andtheworkingvoltagerangeis4~30V.WhatarethecharacteristicsofAD590temperaturesensor?Singlefunction(onlytemperaturemeasurement),smalltemperaturemeasurementerror,lowprice,fastresponsespeed,longtransmissiondistance,smallsize,micropowerconsumption,etc.Itissuitableforremotetemperaturemeasurementandtemperaturecontrolwithoutnon-linearcalibration.Theperipheralcircuitissimple.HowtodetectthequalityofAD590?AD590hasacurrentof273mAat0.Because2113isaWensensitiveresistor5261,itmeansthatitisgreatlyaffectedbythesurroundingtemperature4102.Itisverydifficulttomeasurewithoutrelyingon1653othertools.Giveyousomesuggestions.Whentheambienttemperaturerisesbyonedegree,thecurrentofAD590increasesby1uA.WhatyouhavetodoistoworkwithAD590simultaneouslywiththehelpofahigh-precisiontemperaturetestinstrument.AfterAD590series10Kresistance,measureitsvoltage,thatistosay,itshouldbe2.73Vat0,and2.98Vatroomtemperature25.Forhigheraccuracy,itisrecommendedthatyouusetheelectronicbuildingblocksoftwareArdunioformeasurement,andputthecorrespondingdataintoMATLABforlinearregression.Thebetterthelinearity,themorestablethemeasurement.AD590isnotahigh-precisiontemperaturetestingdevice.Ifhigh-precisiontestingisrequired,othercomponentsarerecommended.WhatisthedifferencebetweenAD590andPT100?AD590isacurrent-typetemperaturesensor.Itconvertstemperaturechangesintocurrentconversion.Thesimplestprocessingistopassaresistor(10K)aftertheoutputtoconvertthecurrentintoavoltage,andthenthroughthedetectionvoltage,thecurrentatthistimecanbededuced.Usetherelationshipbetweencurrentandtemperatureinthesensordatatocalculatethecurrenttemperature.PT100isaresistancetypetemperaturesensor,whichconvertstemperaturechangesintoresistancechanges.ThesimplestprocessistoplacePt100inabridge,usethevoltagedifferenceatthemidpointofthebridgearm,anduseadifferentialamplifiercircuit(instrumentamplifiercircuit)Amplifythevoltage,usetheamplifiergainandbridgestructuredata,andusethedetectedvoltagetoinverselycalculatethecurrentresistancevalue,andusetherelationshipbetweenresistanceandtemperatureinthePT100datasheettocalculatethecurrenttemperature.IsAD590athermocoupleorathermalresistance?Itisneitherathermocouplenorathermalresistance.Themainprincipleistodetectthetemperatureaccordingtothetemperaturechange,theoutputcurrentchange,andthecurrentsize.

IDescriptionThisblogintroducestheworkingprincipleoftheL298-baseddirectPWMspeedcontrolsystem.Atthesametime,thesoftwareandhardwarecomponentsofthesystemarealsogiven.TherunningtestinthelatterpartoftheblogshowsthatthisL298-baseddirectPWMspeedcontrolsystemworksstablyandreliably.Moreover,thespeedregulationrequirementsofDCmotorscanbemet.L298MotorControlArduinoTutorialCatalogIDescriptionIIIntroductionIIIWorkingPrincipleofDCHouseholdWMSpeedControlSystemIVIntroductiontoL298VSoftwareImplementationofPWMSpeedRegulationVIConclusionFAQOrdering&QuantityIIIntroductionForalongtime,becauseDCmotorshavethefollowingcharacteristics:Goodlinearspeedregulationcharacteristics;Simplecontrolfunction;HigherefficiencyExcellentdynamiccharacteristics.Therefore,theDCmotoriswidelyusedinspeedcontrol.Especiallywiththedevelopmentofcomputersinthefieldofhumancontrolandthedevelopmentofhighswitchingfrequency,fullycontrolledsecond-generationpowersemiconductordevices(GTR,GTO,MOSinkstoneT,IGBT,etc.),thepulsewidthmodulation(PWM)DCspeedcontrolsystemisinItismoreandmorecommonlyusedinspeedcontrol.IIIWorkingPrincipleofDCHouseholdWMSpeedControlSystemThePWMspeedcontroldeviceusestheswitchingcharacteristicsofhigh-powertransistorstomodulateafixed-voltageDCpowersupply,andswitchesonandoffatafixedfrequency.Then,changethelengthoftheonandofftimeinacycleasneeded.BychangingthedutycycleofthevoltageonthearmatureoftheDCservomotor,theaveragevoltagecanbechangedtocontrolthemotorspeed.Therefore,thisdeviceisalsocalledaswitchdrivedevice.Figure1.PWMcontroldiagramTheschematicdiagramofPWMcontrolisshowninFigure1.ThecontrollableswitchSisrepeatedlyturnedonandoffatcertaintimeintervals.WhenSisconnected,thepowersupplyUsisappliedtobothendsofthemotorthroughtheswitchS,thepowersupplyprovidesenergytothemotor,andthemotorstoresenergy.WhentheswitchSisoff,thepowersupplyUsisinterruptedtoprovideelectricalenergytothemotor.ButtheenergystoredinthearmatureinductanceduringtheswitchSison.Atthistime,themotorcurrentcontinuestoflowthroughthefreewheelingdiodeVD.ThevoltagewaveformobtainedatbothendsofthemotorisshowninFigure2,andtheaveragevoltageUavcanbeexpressedbythefollowingformula:Whereton:Thetimewhentheswitchisturnedoneachtime;T:Shorttimeperiodwhentheswitchison;:Dutycycle.Itcanbeseenfromtheaboveformulathatchangingtheratiooftheswitch-ontimetontotheswitchingperiodT,thatis,changingthedutycycleofthepulse.Theaveragevoltageacrossthemotoralsochangesaccordingly.Thus,themotorspeediscontrolled.Figure2.PWMcontrolwaveformTherearetwomodulationmethodsforchangingthedutycycle:Oneisthattheswitchingperiodisconstant,andthedutycycleischangedbychangingtheon-pulsewidth.Thatispulsewidthmodulation.Anotherwayistohaveaconstantturn-onpulsewidthandchangethedutycyclebychangingtheswitchingfrequency(f=1/T).Thatispulsefrequencymodulation.SincePFMcontrolreliesonthepulsefrequencytochangethedutycycle,whenitencountersamechanicalresonanceataparticularfrequency,itoftenresultsinsystemvibrationandaudiowhistling.ThisseriousshortcomingmakesPFMcontrolunsuitableinservosystems.Atpresent,thecontrolofDCmotorsismainlybasedontheapplicationofPWMcontrol.IVIntroductiontoL298L298isadualH-bridgehigh-voltagehigh-currentpowerintegratedcircuit,whichdirectlyusesITLlogiclevelcontrol.Itcanbeusedtodriveinductiveloadssuchasrelays,coils,DCmotors,andsteppingmotors.Itsdrivingvoltagecanreach46V,andthetotalDCcurrentcanreach4A.TherearetwoidenticalPWMpoweramplifiercircuitsinside.TheinternalstructureofL298isshowninFigure3.Figure3.HardwarecompositiondiagramofPWMspeedcontrollerAccordingtotheinputandoutputrelationshipofL298,theenablecontrolterminalEnAisconnectedtotheP1.0portoftheAT89C52.ForthePWMsignal,theinputterminalIn2islowlevel,themotorrotatesforward;theinputterminalIn2isthePWMsignal,inputterminalIn1isrecordedaslowlevel,themotorreverses).Whenitislowlevel,the4transistorsonthedrivebridgeareallcutoff,sothatthearmaturecurrentoftherunningmotorisreversedandthemotorstopsfreely.ThespeedofthemotorisrealizedbyadjustingthedutyratioofthePWMsignalbythesingle-chipmicrocomputer.VSoftwareImplementationofPWMSpeedRegulationIntermsofprogramdesign,thegenerationofthePWMpulsesignaloftheMCUcanusethefollowingtwomethods:softwaredelayandtimerdelay.Althoughsoftwaredelayiseasiertoimplement,intheory,itoccupiestoomuchsystemresourcesandisinconvenienttouse.ThePWMspeedcontrollerusesthetimer0interruptmodetogeneratePWMpulse,andthePWMcontrolsubroutineistheinterruptserviceroutineoftimer0.Atthesametime,italsogeneratesasamplingperiod,thatis,theAnzhaosamplingperiodstartsA/Dconversion.ItsprogramflowchartisshownasinFig.4.Figure4.ProgramflowchartVIConclusionBasedontheL298DCmotorPWMspeedregulator,the1/0portoftheA8T9C52microcontrolleroutputsthePWMsignal,anddirectlyusestheTTLleveltocontrolthedrivechipL298toadjustthemotorspeed.Itissimpleandconvenienttocontrol.Andtheexperimentshowsthatthesystemworksstablyandreliably,satisfiesthefunctionalrequirementsofspeedregulation,andhasgreattheoreticalandpracticalvalue.FAQWhatisl298n?ThisL298NMotorDriverModuleisahighpowermotordrivermodulefordrivingDCandStepperMotors.ThismoduleconsistsofanL298motordriverICanda78M055Vregulator.L298NModulecancontrolupto4DCmotors,or2DCmotorswithdirectionalandspeedcontrol.Whatistheuseofl298n?TheL298NisadualH-BridgemotordriverwhichallowsspeedanddirectioncontroloftwoDCmotorsatthesametime.ThemodulecandriveDCmotorsthathavevoltagesbetween5and35V,withapeakcurrentupto2A.Howdoesl298ncontrolDCmotorspeed?1.IfyousendaHIGHsignaltotheenable1pin,motorAisreadytobecontrolledandatthemaximumspeed;2.IfyousendaLOWsignaltotheenable1pin,motorAturnsoff;3.IfyousendaPWMsignal,youcancontrolthespeedofthemotor.Themotorspeedisproportionaltothedutycycle.Whatisl298nmotordrivermodule?ThisL298NMotorDriverModuleisahighpowermotordrivermodulefordrivingDCandStepperMotors.ThismoduleconsistsofanL298motordriverICanda78M055Vregulator.L298NModulecancontrolupto4DCmotors,or2DCmotorswithdirectionalandspeedcontrol.Howdoesl298nmotordriverwork?TheL298NisadualH-BridgemotordriverwhichallowsspeedanddirectioncontroloftwoDCmotorsatthesametime.ThemodulecandriveDCmotorsthathavevoltagesbetween5and35V,withapeakcurrentupto2A.Howdoiuseal298motordriverwithArduino?Startbyconnectingpowersupplytothemotors.InourexperimentweareusingDCGearboxMotors(alsoknownasTTmotors)thatareusuallyfoundintwo-wheel-driverobots.Theyareratedfor3to12V.So,wewillconnectexternal12VpowersupplytotheVCCterminal.WhatisthefunctionofHbridge?AnH-bridgeisanelectroniccircuitthatswitchesthepolarityofavoltageappliedtoaload.ThesecircuitsareoftenusedinroboticsandotherapplicationstoallowDCmotorstorunforwardsorbackwards.Whatisthedifferencebetweenl293dandl298n?L293isquadruplehalf-HdriverwhileL298isdualfull-Hdriver,i.e,inL293allfourinput-outputlinesareindependentwhileinL298,ahalfHdrivercannotbeusedindependently,onlyfullHdriverhastobeused....Hence,heatsinkisprovidedinL298.DescriptionLM3886isahigh-performanceaudiopoweramplifier.Undertheratedworkingvoltage,itiscapableofdelivering68Wofcontinuousaveragepowertoa4loadand38Winto8with0.1%THD+Nfrom20Hz20kHz.TheperformanceoftheLM3886,utilizingitsSelfPeakInstantaneousTemperature(Ke)(SPiKe)protectioncircuitry,putsitinaclassabovediscreteandhybridamplifiersbyprovidinganinherently,dynamicallyprotectedSafeOperatingArea(SOA).SPiKeprotectionmeansthatthesepartsarecompletelysafeguardedattheoutputagainstovervoltage,undervoltage,overloads,includingshortstothesupplies,thermalrunaway,andinstantaneoustemperaturepeaks.TheLM3886maintainsanexcellentsignal-to-noiseratioofgreaterthan92dBwithatypicallownoisefloorof2.0V.ItexhibitsextremelylowTHD+Nvaluesof0.03%attheratedoutputintotheratedloadovertheaudiospectrum,andprovidesexcellentlinearitywithanIMD(SMPTE)typicalratingof0.004%.CatalogDescriptionCADModelsFeaturesApplicationsParametersElectricalCharacteristicsPinoutCircuitDiagramPackageProductComplianceComponentDatasheetProductManufacturerOrdering&QuantityCADModelsLM3886SymbolLM3886FootprintFeatures68WCont.Avg.OutputPowerinto4atVCC=28V38WCont.Avg.OutputPowerinto8atVCC=28V50WCont.Avg.OutputPowerinto8atVCC=35V135WInstantaneousPeakOutputPowerCapabilitySignal-to-NoiseRatio92dBAnInputMuteFunctionOutputProtectionfromaShorttoGroundortotheSuppliesviaInternalCurrentLimitingCircuitryOutputOver-VoltageProtectionagainstTransientsfromInductiveLoadsSupplyUnder-VoltageProtection,notAllowingInternalBiasingtoOccurwhen|VEE|+|VCC|12V,thusEliminatingTurn-OnandTurn-OffTransients11-LeadTO-220PackageWideSupplyRange20V-94VApplicationsComponentstereoCompactstereoSelf-poweredspeakersSurround-soundamplifiersHifg-endstereoTVsParametersAudioinputtypeAnalogInputArchitectureClass-ABSpeakerchannels(Max)MonoPowerstagesupply(Max)(V)94Powerstagesupply(Min)(V)20Load(Min)(ohms)4Outputpower(W)68SNR(dB)110THD+N@1kHz(%)0.03Iq(Typ)(mA)50ControlinterfaceHardwareClosed/openloopOpenAnalogsupply(Min)(V)20Analogsupply(Max)(V)84Powertoparallelbridgetiedload(Max)(W)68PSRR(dB)120Operatingtemperaturerange(C)0to70NumberofTerminals11NumberofFunctions1BrandNameTexasInstrumentsElectricalCharacteristicsThefollowingspecificationsapplyforV+=+28V,V-=-28V,lMUTE=-o.5mAwithRL=4unlessotherwisespecified.LimitsapplyforTA=25℃.PinoutPin1isthepositivepowersupplyV+terminal;Pin2isanemptypin(NC);Pin3istheoutputterminalaftersignalamplification;Pin4isthenegativepowerV-terminal;Pin5isanemptypin(NC)(internallyindependent,butinthe150WLM3886,thispinshouldbeconnectedtoV+);Pin6isanemptypin(NC);Pin7istheground(GND)terminal;Pin8isthemuteend.Ifitisnotneeded,itshouldbeconnectedtothev-terminal.Pin9istheinvertinginputofthesignal;Pin10isthenon-invertinginputterminalofthesignal;Pin11isanemptypin(NC)CircuitDiagramPackageLM3886hastwopackagingmethods.Oneisthatthebackplateisnotinsulatedfromtheinnerelectrode,anditmustbeinsulatedwhenaheatsinkisadded.Theotheristhatthebackplateisinsulatedfromtheinternalelectrodes,sothereisnoneedtoconsiderinsulationwhenaddingaheatsink.ProductComplianceECCNEAR99USHTS8542330001ComponentDatasheetDatasheetLM3886DatasheetProductManufacturerTexasInstrumentsInc.(TI)isanAmericantechnologycompanythatdesignsandmanufacturessemiconductorsandvariousintegratedcircuits,whichitsellstoelectronicsdesignersandmanufacturersglobally.ItsheadquartersareinDallas,Texas,UnitedStates.TIisoneofthetoptensemiconductorcompaniesworldwide,basedonsalesvolume.TexasInstrumentssfocusisondevelopinganalogchipsandembeddedprocessors,whichaccountsformorethan80%oftheirrevenue.TIalsoproducesTIdigitallightprocessing(DLP)technologyandeducationtechnologyproductsincludingcalculators,microcontrollersandmulti-coreprocessors.Todate,TIhasmorethan43,000patentsworldwide.

IIntroductionLM1875isapoweramplifierintegratedblock.Ithasfewperipheralcircuits,largedistortion-freepower,andcanworkwithbothsingleanddualpowersupplies.Italsohasasafeworkingareaprotection(inductiveload)foroverload,overheatingandreversepotentialsuppressioninthecircuit,suitableforhigh-gradeaudiocircuits.AndLM1875isalsosuitableforaudioamplification,servoamplification,bridgeamplification,andpoweramplificationintestsystems.ThisVedioTakeLM1875asanExampletoExplaintheBridgedAudioAmplifierCatalogIIntroductionIIDCNegativeFeedbackBTLPowerAmplifierCircuitIII20WSingle-powerAmplifierCircuitIVLM1875PowerAmplifierCircuitwithHighandLowAdjustmentVCurrentFeedbackPowerAmplifierCircuitOrdering&QuantityIIDCNegativeFeedbackBTLPowerAmplifierCircuitTheLM1875amplifiercircuitissimple,wherethesoundisbeautiful,andhasthetimbreoftheamplifier.Thepoweramplifierproducedbyitcanoutputpowerupto25Wunderpositiveandnegative25Vvoltage.Inordertooutputmorepower,itcanbeconnectedtoBTLcircuit.Theoutputpowerofthefollowingcircuitexceeds60W(8ohmspeaker),whichisdesignedasacurrentnegativefeedbackcircuit,andthesoundismorebeautiful.Inaddition,themainrecommendationofthisboardistocancelC11andC21inFigure1,andaddacapacitorattheinput(changeC11here).ChangethecircuittoaDCamplifier,thesoundeffectwillbebetter.Figure1.LM1875CuircuitIII20WSingle-powerAmplifierCircuitThecircuitisshowninFigure3.ThebasicworkingprincipleoftheLM1875singlepowersupplyandthedualpowersupplyisthesame.Thedifferenceisthatwhenthesinglepowersupplyisused,R1andR2areusedforvoltagedivision,while1/2VCCistakenasthebiasvoltageandaddedtoR3topin1,makingtheoutputvoltagechangeupanddownbasedon1/2VCC.Therefore,themaximumdynamicrangecanbeobtained.Figure2.LM1875CuircuitIVLM1875PowerAmplifierCircuitwithHighandLowAdjustmentFigure3.LM1875CuircuitThecircuitaboveiscomposedofthreeparts:AnattenuatedtonecontrolcircuitcontrolledbyhighandlowsoundsAnLM1875amplifiercircuitApowersupplycircuit.Thetonepartusesattenuatingtonecircuitscontrolledbyhighandlowbassrespectively,amongwhichR02,R03,C02,C01,W02formabasscontrolcircuit;C03,C04,W03formatreblecontrolcircuit;R04istheisolationresistance,W01isthevolumecontroller,adjustingthevolumeoftheamplifier;C05istheDCblockingcapacitor,topreventtheLM1875DCpotentialofthesubsequentstagefromaffectingthetonecircuitoftheprecedingstage.TheamplifyingcircuitadoptsLM1875,R08,R09,C06.Amongthem,themagnificationofthecircuitisdeterminedbytheratioofR08andR09;andC06isusedtostabilizetheDCzeropotentialdriftofthe4thpinofLM1875,butithasacertainimpactonthesoundquality;C07,R10istopreventtheamplifierfromgeneratinglow-frequencyself-excitation.Theloadimpedanceofthisamplifieris416.Figure4.LM1875CuircuitAsforthepowersupply,inordertoensurethesoundquality,theoutputpowerofthepowertransformershouldnotbelessthan80W,andtheoutputvoltageis2*25V.Thefiltercapacitorusestwo2200F/25Velectrolyticcapacitorsinparallel,andthepositiveandnegativepowersuppliessharefour2200F/25Vcapacitors.Thetwo104monolithiccapacitorsarehigh-frequencyfiltercapacitors,whicharebeneficialtothesoundqualityoftheamplifier.VCurrentFeedbackPowerAmplifierCircuitThecurrentmodepoweramplifierhasbettersoundquality.ThecurrentmodepoweramplifiercircuitusingthepoweramplifierintegratedcircuitLM1875isshowninFigure5.Inthefigure,theresistorR3connectedinserieswiththespeakerRLhasaverysmallvalue.ThecurrentflowingthroughthespeakerflowsthroughR3,andthesamplingfeedbackvoltagegeneratedatbothendsisproportionaltotheoutputcurrent.ThevoltageformedonR3issenttothefeedbackinputoftheamplifierthroughR2toformacurrentnegativefeedback,whichincreasestheoutputimpedanceoftheamplifierandreducesthedampingcoefficient.Theso-calledRubernetworkwascancelledinthecircuit,andonlyC4wasusedastheleadcompensation.AlthoughthesettingofR2preventstheoutputfeedbackcurrentfrombeingfedback100%tothenegativeinputterminal,itpreventstheharmfuleffectsoflargefeedbackontheinputterminal;Atthesametime,thebiasofthepositiveandnegativeinputterminalsisbalanced,andtheDCoffsetoftheoutputterminaliseliminated.Figure5.LM1875CuircuitFirstsoldertwosmall0.22uFcapacitorstothepin③and⑤,andweldtheotherendsofthemtogetherasthegroundterminal.Regardingtheresistancetogrounding,allarebentandweldedatthispoint.The24Vpowercordandoutputcordaredirectlysolderedtotherelevantpins.Short-circuittheinputterminaltoground,soldera10resistortotheRLspeaker,andtestthevoltageoftheoutputterminaltogroundafterpower-on.Ifitislessthan100mVandthereisbasicallynodeviationafterhalfanhour,youcandisconnecttheinputshortcircuitandconnectthespeaker.Afterreadingtheblog,haveyoubetterunderstandLM1875?IfyouarealsointerestedindetailedintroductiontoLM1875,youmaywishtobrowserighthererightnow!Finally,ifyouhaveanyquestionsaboutLM1875,pleasedonothesitatetoleaveamessageinthecommentsectionbelow!IntroductionTheLM393comparatorcanberegardedasequivalenttothemostpopularversionoftheLM358operationalamplifier.Althoughanyoperationalamplifiercanbeusedasavoltagecomparator,theLM393comparatorprovesitsadvantagebyprovidinganopencollectoroutputtomakeitsuitablefordrivingloads.Theoutputtransistorcandriveloadsupto50Vand50mAandissuitablefordrivingmostTTL,MOSandRTLloads.Thetransistorcanalsoisolatetheloadfromthesystemground.ThisVedioIntroducesLM393DualComparatorwithOpenCollectorOutputfromIntegratedCircuitCatalogIntroductionCADCAESymbolsDocumentandMediaECCNUNSPSCLM393PinConfigurationandFunctionsPopularitybyRegionBasicParametersProductManufacturerFeaturesProductRangeAdvantagesAlternativeModelsFunctionalBlockDiagramOrdering&QuantityDocumentandMediaComponentDatasheetLM393DatasheetApplicationNotesApplicationDesignGuidelinesforLM393LM393PinConfigurationandFunctionsTheLM393datasheetprovidedaboveisforyourreference,sothatyoucanunderstandthephysicaldimensionsofallpackagesinmoredetail.Theconfigurationofall8pinsandthefunctionofeachpinareasfollows:ThefunctionofLM393pinsareasfollows:BasicParametersNumberofchannels2OutputtypeOpen-collectorPropagationdelaytime1.3sVs(Max)36VVs(Min)2VVos(offsetvoltage@25C)(Max)5mVIqperchannel(Typ)0.225mAInputbiascurrent(+/-)(Max)50nARail-to-railOutRatingCatalogOperatingtemperaturerange0℃to70℃FeaturesStandardcomparatorVICR(Max)34.5VVICR(Min)0VApprox.price1ku|0.06US$FeaturesImprovedspecificationsofB-versionMaximumrating:upto38VESDrating(HBM):2kVLowinputoffset:0.37mVLowinputbiascurrent:3.5nALowsupply-current:200ApercomparatorFasterresponsetimeof1secExtendedtemperaturerangeforLM393BAvailableintiny2x2mmWSONpackageB-versionisdrop-inreplacementforLM293,LM393andLM2903,AandVversionsCommon-modeinputvoltagerangeincludesgroundDifferentialinputvoltagerangeequaltomaximumratedsupplyvoltage:38VLowoutputsaturationvoltageOutputcompatiblewithTTL,MOS,andCMOSAdvantagesVacuumrobotSinglephaseUPSServerPSUCordlesspowertoolWirelessInfrastructureApplicancesBuildingAutomationFactoryautomationcontrolMotordrivesInfotainmentclusterFunctionalBlockDiagramCADCAESymbolsPackagePinsDownloadPDIP(P)8ViewoptionsSO(PS)8ViewoptionsSOIC(D)8ViewoptionsTSSOP(PW)8ViewoptionsVSSOP(DGK)8ViewoptionsECCNUNSPSCDescriptionValueECCNCodeEAR99HTSCode8542.39.00.01PopularitybyRegionProductManufacturerTexasInstrumentsInc.(TI)isanAmericantechnologycompanythatdesignsandmanufacturessemiconductorsandvariousintegratedcircuits,whichitsellstoelectronicsdesignersandmanufacturersglobally.ItsheadquartersareinDallas,Texas,UnitedStates.TIisoneofthetoptensemiconductorcompaniesworldwide,basedonsalesvolume.TexasInstrumentssfocusisondevelopinganalogchipsandembeddedprocessors,whichaccountsformorethan80%oftheirrevenue.TIalsoproducesTIdigitallightprocessing(DLP)technologyandeducationtechnologyproductsincludingcalculators,microcontrollersandmulti-coreprocessors.Todate,TIhasmorethan43,000patentsworldwide.ProductRangeDevicesBoardsDeveloperToolsARMPROCESSORSAUTOMOTIVEPRODUCTSIDENTIFICATIONSECURITYKinetisCortex-MMicrocontrollersIn-VehicleNetworkNFCLPCCortex-MMicrocontrollersMicrocontrollersandProcessorsRFIDAlternativeModelsLM741LM358LM339LM324Afterreadingtheblog,haveyoubetterunderstandLM393?IfyouarealsointerestedinhowtoDIYyoursolartrackingcarbyusingLM393,youmaywishtobrowserighthererightnow!Finally,ifyouhaveanyquestionsaboutLM393,pleasedonothesitatetoleaveamessageinthecommentsectionbelow!

IIntroductionTheLM393isadualvoltagecomparator.thismeansthatitaccepts2inputsforcomparison.TheoutputloadresistanceofLM393comparatorcanbeconnectedtoanypowersupplyvoltagewithintheallowablepowersupplyvoltagerange,andisnotlimitedbythevoltagevalueoftheVccterminal.ThisoutputcanbeusedasasimpleopencircuittogroundSPS(whentheloadresistorisnotused),thesinkcurrentoftheoutputpartislimitedbythevalueofthedriverandthedevicethatcanbeobtained.Whenthelimitcurrent(16mA)isreached,theoutputtransistorwillexitandtheoutputvoltagewillrisequickly.Inthisblog,wewilldiscuss3waystousetheLM393comparatortobuildcircuits,including:InfraredObstacleAvoidanceModule,Ni-CdBatteryCharger,andPWMModulationCircuit.LM393imagesareforreferenceonly.Figure1.LM393ComparatorCatalogIIntroductionIILM393BasedInfraredObstacleAvoidanceModule2.1ModuleDescription2.2DescriptionofModuleParameters2.3ModuleInterfaceDescriptionIIILM393Ni-CdBatteryChargerIVLM393PWMModulationCircuitOrdering&QuantityIILM393BasedInfraredObstacleAvoidanceModuleFigure2.LM393InfraredObstacleAvoidanceModule2.1ModuleDescriptionThesensormodulehasstrongadaptabilitytoambientlight.Ithasapairofinfraredemittingandreceivingtubes.Thetransmittingtubeemitsinfraredraysofafrequency.Whenitencountersanobstacle(reflectingsurface)inthedetectiondirection,itwillbereflectedbackandreceivedbythereceivingtube.Afterthereceivedinfraredlightisprocessedbythecomparatorcircuit,thegreenindicatorlightwilllightup,andthesignaloutputinterfaceoutputsadigitalsignal(alow-levelsignal).Thedetectiondistancecanbeadjustedbythepotentiometerknob.Theeffectivedistancerangeis2-30cm,andtheoperatingvoltageItis3.3V-5V.Thedetectiondistanceofthesensorcanbeadjustedbyapotentiometer,whichhasthecharacteristicsofsmallinterference,easyassemblyandconvenientuse.Itcanbewidelyusedinmanysituationssuchasrobotobstacleavoidance,obstacleavoidancetrolley,pipelinecountingandblackandwhitelinetracking.2.2DescriptionofModuleParametersWhenthemoduledetectsanobstaclesignalinfront,thegreenindicatoronthecircuitboardlightsup,andtheOUTportcontinuouslyoutputsalow-levelsignal.Thedetectiondistanceofthismoduleis2~30cm,andthedetectionangleis35.Inaddition,thedetectiondistancecanbeadjustedbythepotentiometer:Byadjustingthepotentiometerclockwise,thedetectiondistanceincreases;Byadjustingthepotentiometercounterclockwise,thedetectiondistancedecreases;Thesensorisactiveinfraredreflectiondetection,sothereflectivityandshapeofthetargetisthekeytothedetectiondistance.Amongthem,theblackdetectiondistanceissmallandthewhiteislarge;thedistanceofsmallareasissmall,andthedistanceoflargeareasislarge;TheoutputportOUTofthesensormodulecanbedirectlyconnectedtotheIOportofthesingle-chipmicrocomputer,oritcandirectlydrivea5Vrelay;connectionmode:VCC-VCC;GND-GND;OUT-IO;TheLM393comparatorhasthecharacteristicsofstableoperation;3-5VDCpowersupplycanbeusedtopowerthemodule.Whenthepoweristurnedon,theredpowerindicatorlights;has3mmscrewholesforeasyfixingandinstallation;Circuitboardsize:3.2CM*1.4CM;Themodulehasadjustedthethresholdcomparisonvoltagethroughthepotentiometer.Unlessunderspecialcircumstances,pleasedonotadjustthepotentiometeratwill.2.3ModuleInterfaceDescriptionVCCexternal3.3V-5Vvoltage(canbedirectlyconnectedto5vmicrocontrollerand3.3vmicrocontroller);ConnectGNDexternallytoGND;OUTsmallboarddigitaloutputinterface(0and1);Theworkingcurrentiswithin10ma;BarriersensormoduleasshowninFigure3.Figure3.InfraredReflectiveSensorModuleIIILM393Ni-CdBatteryChargerThecost-effectivenickel-cadmiumbatterychargerformedbyLM393comparatorisshowninFigure4,whichhasthefollowingcharacteristics:Figure4.Nickel-CadmiumBatteryChargerConstantcurrentchargingisinterspersedwithlargecurrentdischarge.Theconstantcurrentchargingcurrentisabout300mA,andthedischargecurrentincreasesasthebatteryvoltageincreases.Whenthebatteryisnearlyfull,thedischargecurrentreaches400mA.Chargefor1.5secondsanddischargefor0.5secondsatintervals.Afterthehighcurrentchargingiscompleted,thereisabout5mAtricklecharging.Thebatteryvoltageisdetectedduringdischarge.Becausethevoltageduringchargingisalwayshigherthanthevoltageduringdischarging.Ifthereisanerrorbetweenthedetectionandtheactualworkingstateofthebatteryduringcharging,thedetectioncanmorereflectthecapacityofthebatterywhendischarging.Thenumberofrechargeablebatteriescanbe1to4.For500mAhnickel-cadmiumbatteries,thechargingtimeisabout2hours,whichcanmeetthegeneralneeds.IVLM393PWMModulationCircuitWeknowthatPWMgenerallyrequiresasawtoothwaveandacontrolvoltagetobecomparedwithacomparatortoobtainaPWMpulse.Thecomparator2ofLM393votagecomparatorwillbeusedasaPWMcomparator,whosenon-invertinginputendisthecontrolvoltageinputend,andtheinvertinginputendisthesawtoothwaveinputend.Theoutputterminal(pin7)isusedastheoutputterminaltosendthePWMdimmingsignaltotheIRNpinoftheIRS2540/1viatheisolationdiodeVD.TheLM393circuitofPWMModulationisshowninFigure5below.Figure5.PWMModulationCircuitThegenerationofthesawtoothwaveisrealizedbythecomparator1ofLM393.IfyoudonotlookatthecapacitorC1,thecomparator1isamultivibratorwithasquarewaveoutput.Inordertoobtainthesawtoothwave,acapacitorC1isconnectedinparallelwiththeCOMendoftheoutputendofthecomparator1.ThisisactuallythechargingprocessoftheoutputterminalsR1andC1ofthecomparator1.Ifthecapacitanceofthiscapacitorislargeenough,butbecausethechargingofC1requiresR1,andthedischargeofC1istheoutputtransistorofthecomparator,thentheriseandfallofthevoltageattheoutputofthecomparatorwillbeasymmetric,whichwillformanoscillatingsawtoothwave.Figure6.OscillatingSawtoothWaveDuetotheVBUSapplicationofthepowersupplyofthecircuitinthefigure,itneedstobesteppeddownwithRS,andthevoltageregulationofVD2andthepowersupplybypasscapacitorsC3andC4arerequired.Afterreadingtheblog,haveyoubetterunderstandLM393?IfyouarealsointerestedinhowtoDIYyoursolartrackingcarbyusingLM393,youmaywishtobrowserighthererightnow!Finally,ifyouhaveanyquestionsaboutLM393,pleasedonothesitatetoleaveamessageinthecommentsectionbelow!IntroductionLM567isahigh-stabilitylow-frequencyintegratedphase-lockedloopdecoder.Duetoitsgoodnoisesuppressionabilityandcenterfrequencystability,itiswidelyusedinthedecodingofvariouscommunicationequipmentandthedemodulationcircuitofAMandFMsignals.LM567Imagesareforreferenceonly.LM567ToneDecoderCatalogIntroductionDocumentsandMediaPinConfigurationandFunctionsBasicParametersFeaturesApplicationsFunctionalBlockDiagramCircuitDiagramECCNUNSPSCProductManufacturerProductRangeOrdering&QuantityDocumentsandMediaComponentDatasheetsLM567(C)PinConfigurationandFunctionsThedatasheetprovidedaboveisforyourreference,sothatyoucanunderstandthephysicaldimensionsofallpackagesinmoredetail.Theconfigurationofall8pinsandthefunctionofeachpinareasfollows:PinConfigurationAndthefunctionofall8pinsandthefunctionofeachpinareasfollows:PinFunctionBasicParametersBrandNameTexasInstrumentsECCNCodeEAR99FactoryLeadTime1WeekHTSCode8542.39.00.01JESD-30CodeR-PDSO-G8JESD-609Codee3Length4.9mmManufacturerTexasInstrumentsManufacturerPartNumberLM567CMX/NOPBMoistureSensitivityLevel1NumberofFunctions1NumberofTerminals8OperatingTemperature-Max70CPackageBodyMaterialPLASTIC/EPOXYPackageCodeSOPPackageDescriptionSOP-8PackageEquivalenceCodeSOP8,.23PackageShapeRECTANGULARPackageStyleSMALLOUTLINEPartLifeCycleCodeActivePartPackageCodeSOICPbfreeCodeYesPeakReflowTemperature260℃PinCount8QualificationStatusNotQualifiedReachComplianceCodeCompliantRiskRank0.62RohsCodeYesSeatedHeight-Max1.75mmSupplyCurrent-Max15mASupplyVoltage-Nom5VSurfaceMountYESTelecomICTypeTONEDECODERCIRCUITTemperatureGradeCOMMERCIALTerminalFinishMatteTin(Sn)TerminalFormGULLWINGTerminalPitch1.27mmTerminalPositionDUALTime@PeakReflowTemperature-Max(s)NOTSPECIFIEDWidth3.91mmFeatures20to1FrequencyRangeWithanExternalResistorLogicCompatibleOutputWith100-mACurrentSinkingCapabilityBandwidthAdjustableFrom0to14%HighRejectionofOutofBandSignalsandNoiseImmunitytoFalseSignalsHighlyStableCenterFrequencyCenterFrequencyAdjustablefrom0.01Hzto500kHzApplicationsTheLM567tonedecoderisadevicecapableofdetectingwhetheraninputsignaliswithinaselectabledetectionrange.Thedevicehasanopencollectortransistoroutput,soanexternalresistorisrequiredtoreachtheappropriatelogiclevels.Whentheinputsignalisinthedetectionband,thedeviceoutputchangestotheLOWstate.TheinternalfreeoperatingfrequencyoftheVCOdefinesthecenterfrequencyofthedetectionband.AnexternalRCfilterisrequiredtoadjustthisfrequency.Thebandwidthinwhichthedevicewilldetectthedesiredfrequencydependsonthecapacityoftheloopfilterterminal.Usuallya1Fcapacitorisconnectedtothispin.LM567isgenerallyusedinthefollowingsituations:TouchToneDecodingPrecisionOscillatorFrequencyMonitoringandControlWideBandFSKDemodulationUltrasonicControlsCarrierCurrentRemoteControlsCommunicationsPagingDecodersFunctionalBlockDiagramCircuitDiagramThefollowingdescribestheclassiccircuitdiagramofthephase-lockedloopLM567usedincarriercommunicationapplications.Therearemanyapplicationsforit,butthethreecircuitsdescribedbelowhaveallbeentestedbypracticeforreferencebythosewholovecarriercommunication.ClassicCircuitDiagram(1)ClassicCircuitDiagram(2)ClassicCircuitDiagram(3)ECCNUNSPSCDescriptionValueECCNCodeEAR99HTSCode8542.39.00.01ProductManufacturerTexasInstrumentsInc.(TI)isanAmericantechnologycompanythatdesignsandmanufacturessemiconductorsandvariousintegratedcircuits,whichitsellstoelectronicsdesignersandmanufacturersglobally.ItsheadquartersareinDallas,Texas,UnitedStates.TIisoneofthetoptensemiconductorcompaniesworldwide,basedonsalesvolume.TexasInstrumentssfocusisondevelopinganalogchipsandembeddedprocessors,whichaccountsformorethan80%oftheirrevenue.TIalsoproducesTIdigitallightprocessing(DLP)technologyandeducationtechnologyproductsincludingcalculators,microcontrollersandmulti-coreprocessors.Todate,TIhasmorethan43,000patentsworldwide.ProductRangeDevicesBoardsDeveloperToolsARMPROCESSORSAUTOMOTIVEPRODUCTSIDENTIFICATIONSECURITYKinetisCortex-MMicrocontrollersIn-VehicleNetworkNFCLPCCortex-MMicrocontrollersMicrocontrollersandProcessorsRFIDAfterreadingtheblog,haveyoubetterunderstandLM567?IfyouarealsointerestedinhowtouseLM567totestthespeedofyourmotorcycle,youmaywishtobrowserighthererightnow!Finally,ifyouhaveanyquestionsaboutLM567,pleasedonothesitatetoleaveamessageinthecommentsectionbelow!