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L298DescriptionTheL298isanintegratedmonolithiccircuitina15-leadMultiwattandPowerSO20packages.Itisahighvoltage,ahighcurrentdualfull-bridgedriverdesignedtoacceptstandardTTLlogiclevelsanddriveinductiveloadssuchasrelays,solenoids,DCandsteppingmotors.Twoenableinputsareprovidedtoenableordisablethedeviceindependentlyoftheinputsignals.Theyaremostlyused:whenitisneededtooperatedifferentloadslikemotorsandsolenoidetcwhereanH-BridgeisrequiredwhenhighpowermotordriverisrequiredwhenthecontrolunitcanonlyprovideTTLoutputswhencurrentcontrolandPWMoperablesingle-chipdeviceisneededCatalogL298DescriptionL298CircuitDiagramL298FeaturesandSpecificationsL298PinConfigurationsandFunctionsL298PackageOutlineandMechanicalDataWheretouseL298ICHowtouseL298ICL298ApplicationsL298ComparewithOtherMotorsProductManufacturerComponentDatasheetFAQOrdering&QuantityL298CircuitDiagramL298FeaturesandSpecificationsOperatingsupplyvoltageupto46vTotalDCcurrentupto4A25wratedpower2enablecontrolterminalstoenableordevicewithoutinputtingsignals.Abletodriveatwo-phasesteppermotor,four-phasesteppermotorortwoDCmotorsLowsaturationvoltageOvertemperatureprotectionLogical0inputvoltageupto1.5V(highnoiseimmunity)Operatingtemperature:-23Cto130CStorageTemperature:-40Cto150CL298PinConfigurationsandFunctionsPinoutFunctions:L298PackageOutlineandMechanicalDataL298(Multiwatt15V)L298(Multiwatt15H)L298(PowerSO20)WheretouseL298ICHereareafewareaswhereL298ispreferred:L298isbasicallyusedwhereH-BRIDGEisrequired.Whereahighpowermotordriverisrequired.Inthemarked,thereareH-bridgeslikeL293whichareusedforthelowpoweredapplicationwhileL298isspeciallydesignedforthehighpowerapplications.WherecurrentcontrolandPWMoperablesingle-chipdeviceisneeded.ThechipispreferredwhencontrolunitcanonlyprovideTTLoutputAlso,thechipdoesnotneedanyadditionalcomponentstobeinstalledforoperating.HowtouseL298ICForunderstandingtheworkingofL298IC,considerthesimplecircuitconfigurationshownbelow.HereweareusingoneofH-BRIDGESofl298IC.AsshowninthecircuitwehavetwopushbuttonsQ1andQ2whichactascontrolsinputsforbridge-A.TheselogicinputsareprovidedbyMicrocontrollerorMicroprocessorinapplicationcircuits.ThefourdiodesareFLYBACKdiodesusedforprotectingtheICforminductivevoltagespikes.Theenablepinispulledhighthrougharesistorsobridge-Awillbefunctioningallthetime.Ifitspulledtogroundthebridge-Awillbedisablednomattertheinputcontrollogic.AfterallthecircuitaresetupweneedtopressthebuttonsQ1andQ2tochangetheflowofcurrentbetweenpinsOUT1andOUT2.Thelogiccontroltableisgivenbelow.INPUTSFUNCTIONQ1=HIGH,Q2=LOWForwardcurrentQ1=LOW,Q2=HIGHReversecurrentQ1=Q2FastMOTORstopSoifonlyQ1ispressed,thecurrentflowsfromOUT1toOUT2.WiththatMOTORrotatesclockwisedirection.IfonlyQ2ispressed,thecurrentflowsfromOUT2toOUT1.WiththatMOTORrotatesanti-clockwisedirection.IfbothbuttonsarepressedorreleasedsimultaneouslytheMOTORcomestostopimmediately.Inthisway,wecancontrolthemotorrotationusingtheL298chip.L298ApplicationsRoboticarmsRobotsRelaydriversVendingmachinesIndustrialmachinesEngineeringsystemsMeasuringinstrumentsHobbyprojectsL298ComparewithOtherMotorsWithsomanymotordriverscurrentlysuchasServoMotorsandsteppermotors,whatreallyarethedifferencesbetweenthemotordriversandwhichonetochoose?Noworries,aswehavecraftedatablejustforyoutocomparethevariousmotordriverssoyouknowwhichmotordriverfitsthebestforyourproject.TypeMotorDriversChipActuatorWorkingVoltageWorkingCurrentGroveGroveI2CMotorDriverL298N2DCmotoror1Stepper6v-15v2.0Aeach(Max)GroveI2CMotorDriver(TB6612FNG)TB6612FNG2DCmotoror1Stepper2.5v-13.5v(5Avg,15vMax)1.2A(Avg)to3.2A(Max)GroveI2CMiniMotorDriverDRV88302DCMotor2.75v-6.8v0.2Ato1AeachShieldMotorShieldV2.0L298N2DCmotoror1Stepper6v-15v2.0Aeach(Max)4AMotorShieldMC339322DCMotor6v-28v5.0Aeach(Max)BrushlessMotorShield(TB6605FTG)TB6605FTG1DCBrushlessMotor9v-24v-ProductManufacturerSTmicroelectronics(ST)groupwasestablishedinJune1988asaresultofthemergerofSGSMicroelectronicsofItalyandThomsonOfFrance.InMay1998SGS-ThomsonMicroelectronicschangeditsnametoSTmicroelectronicsLimited.Itistheworldslargestmanufacturerofdedicatedanalogchipsandpowerconversionchips,theworldslargestsupplierofindustrialsemiconductorsandset-topboxchips,andaworldleaderindiscretecomponents,mobilephonecameramodules,andautomotiveintegratedcircuits.ComponentDatasheetL298DatasheetFAQWhatisl298n?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.HowdoIuseanl298motordriverwithArduino?Startbyconnectingpowersupplytothemotors.Inourexperiment,weareusingDCGearboxMotors(alsoknownasTTmotors)thatareusuallyfoundintwo-wheel-driverobots.Theyareratedfor3to12V.So,wewillconnecttheexternal12VpowersupplytotheVCCterminal.WhatisthefunctionoftheHbridge?AnH-bridgeisanelectroniccircuitthatswitchesthepolarityofavoltageappliedtoaload.ThesecircuitsareoftenusedinroboticsandotherapplicationstoallowDCmotorstorunforwardsorbackwards.Whatisthedifferencebetweenl293dandl298n?L293isaquadruplehalf-HdriverwhileL298isdualfull-Hdriver,i.e,inL293allfourinput-outputlinesareindependentwhileinL298,ahalfHdrivercannotbeusedindependently,onlyfullHdriverhastobeused....Hence,heatsinkisprovidedinL298.

L298DescriptionTheL298isanintegratedmonolithiccircuitina15-leadMultiwattandPowerSO20packages.Itisahighvoltage,ahighcurrentdualfull-bridgedriverdesignedtoacceptstandardTTLlogiclevelsanddriveinductiveloadssuchasrelays,solenoids,DCandsteppingmotors.Twoenableinputsareprovidedtoenableordisablethedeviceindependentlyoftheinputsignals.Theyaremostlyused:whenitisneededtooperatedifferentloadslikemotorsandsolenoidetcwhereanH-BridgeisrequiredwhenhighpowermotordriverisrequiredwhenthecontrolunitcanonlyprovideTTLoutputswhencurrentcontrolandPWMoperablesingle-chipdeviceisneededCatalogL298DescriptionL298CircuitDiagramL298FeaturesandSpecificationsL298PinConfigurationsandFunctionsL298PackageOutlineandMechanicalDataWheretouseL298ICHowtouseL298ICL298ApplicationsL298ComparewithOtherMotorsProductManufacturerComponentDatasheetFAQOrdering&QuantityL298CircuitDiagramL298FeaturesandSpecificationsOperatingsupplyvoltageupto46vTotalDCcurrentupto4A25wratedpower2enablecontrolterminalstoenableordevicewithoutinputtingsignals.Abletodriveatwo-phasesteppermotor,four-phasesteppermotorortwoDCmotorsLowsaturationvoltageOvertemperatureprotectionLogical0inputvoltageupto1.5V(highnoiseimmunity)Operatingtemperature:-23Cto130CStorageTemperature:-40Cto150CL298PinConfigurationsandFunctionsPinoutFunctions:L298PackageOutlineandMechanicalDataL298(Multiwatt15V)L298(Multiwatt15H)L298(PowerSO20)WheretouseL298ICHereareafewareaswhereL298ispreferred:L298isbasicallyusedwhereH-BRIDGEisrequired.Whereahighpowermotordriverisrequired.Inthemarked,thereareH-bridgeslikeL293whichareusedforthelowpoweredapplicationwhileL298isspeciallydesignedforthehighpowerapplications.WherecurrentcontrolandPWMoperablesingle-chipdeviceisneeded.ThechipispreferredwhencontrolunitcanonlyprovideTTLoutputAlso,thechipdoesnotneedanyadditionalcomponentstobeinstalledforoperating.HowtouseL298ICForunderstandingtheworkingofL298IC,considerthesimplecircuitconfigurationshownbelow.HereweareusingoneofH-BRIDGESofl298IC.AsshowninthecircuitwehavetwopushbuttonsQ1andQ2whichactascontrolsinputsforbridge-A.TheselogicinputsareprovidedbyMicrocontrollerorMicroprocessorinapplicationcircuits.ThefourdiodesareFLYBACKdiodesusedforprotectingtheICforminductivevoltagespikes.Theenablepinispulledhighthrougharesistorsobridge-Awillbefunctioningallthetime.Ifitspulledtogroundthebridge-Awillbedisablednomattertheinputcontrollogic.AfterallthecircuitaresetupweneedtopressthebuttonsQ1andQ2tochangetheflowofcurrentbetweenpinsOUT1andOUT2.Thelogiccontroltableisgivenbelow.INPUTSFUNCTIONQ1=HIGH,Q2=LOWForwardcurrentQ1=LOW,Q2=HIGHReversecurrentQ1=Q2FastMOTORstopSoifonlyQ1ispressed,thecurrentflowsfromOUT1toOUT2.WiththatMOTORrotatesclockwisedirection.IfonlyQ2ispressed,thecurrentflowsfromOUT2toOUT1.WiththatMOTORrotatesanti-clockwisedirection.IfbothbuttonsarepressedorreleasedsimultaneouslytheMOTORcomestostopimmediately.Inthisway,wecancontrolthemotorrotationusingtheL298chip.L298ApplicationsRoboticarmsRobotsRelaydriversVendingmachinesIndustrialmachinesEngineeringsystemsMeasuringinstrumentsHobbyprojectsL298ComparewithOtherMotorsWithsomanymotordriverscurrentlysuchasServoMotorsandsteppermotors,whatreallyarethedifferencesbetweenthemotordriversandwhichonetochoose?Noworries,aswehavecraftedatablejustforyoutocomparethevariousmotordriverssoyouknowwhichmotordriverfitsthebestforyourproject.TypeMotorDriversChipActuatorWorkingVoltageWorkingCurrentGroveGroveI2CMotorDriverL298N2DCmotoror1Stepper6v-15v2.0Aeach(Max)GroveI2CMotorDriver(TB6612FNG)TB6612FNG2DCmotoror1Stepper2.5v-13.5v(5Avg,15vMax)1.2A(Avg)to3.2A(Max)GroveI2CMiniMotorDriverDRV88302DCMotor2.75v-6.8v0.2Ato1AeachShieldMotorShieldV2.0L298N2DCmotoror1Stepper6v-15v2.0Aeach(Max)4AMotorShieldMC339322DCMotor6v-28v5.0Aeach(Max)BrushlessMotorShield(TB6605FTG)TB6605FTG1DCBrushlessMotor9v-24v-ProductManufacturerSTmicroelectronics(ST)groupwasestablishedinJune1988asaresultofthemergerofSGSMicroelectronicsofItalyandThomsonOfFrance.InMay1998SGS-ThomsonMicroelectronicschangeditsnametoSTmicroelectronicsLimited.Itistheworldslargestmanufacturerofdedicatedanalogchipsandpowerconversionchips,theworldslargestsupplierofindustrialsemiconductorsandset-topboxchips,andaworldleaderindiscretecomponents,mobilephonecameramodules,andautomotiveintegratedcircuits.ComponentDatasheetL298DatasheetFAQWhatisl298n?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.HowdoIuseanl298motordriverwithArduino?Startbyconnectingpowersupplytothemotors.Inourexperiment,weareusingDCGearboxMotors(alsoknownasTTmotors)thatareusuallyfoundintwo-wheel-driverobots.Theyareratedfor3to12V.So,wewillconnecttheexternal12VpowersupplytotheVCCterminal.WhatisthefunctionoftheHbridge?AnH-bridgeisanelectroniccircuitthatswitchesthepolarityofavoltageappliedtoaload.ThesecircuitsareoftenusedinroboticsandotherapplicationstoallowDCmotorstorunforwardsorbackwards.Whatisthedifferencebetweenl293dandl298n?L293isaquadruplehalf-HdriverwhileL298isdualfull-Hdriver,i.e,inL293allfourinput-outputlinesareindependentwhileinL298,ahalfHdrivercannotbeusedindependently,onlyfullHdriverhastobeused....Hence,heatsinkisprovidedinL298.

IDescriptionLM1875isapoweramplifierintegratedblockchip.Itssuperiorperformanceandattractivetonehavebeenacceptedbymanyenthusiasts,anditwasalltherageinthe1990s.LM1875adoptsTO-220packagestructure,whichisshapedlikeamid-powertube,smallinsize,simpleinperipheralcircuits,andlargeinoutputpower.Theintegratedcircuitintroducedinthisblogisequippedwithoverload,overheatingandinductiveloadreversepotentialsafetyprotection,whichisoneoftheidealchoicesforhigh-endaudio.Figure1.LM1875CatalogIDescriptionIILM1875ParametersIIILM1875CircuitPrincipleIVLM1875CircuitAssemblyandDebuggingVIntheEndOrdering&QuantityIILM1875ParametersVoltageRange16~60VQuiescentCurrent50MmAOutputPower25WHarmonicDistortion0.02%,whenf=1kHz,RL=8,P0=20WRatedGain26dB,whenf=1kHzWorkingVoltage25VConversionRate18V/SIIILM1875CircuitPrincipleThiscircuitiscomposedofanattenuatedtonecontrolcircuitcontrolledseparatelyforhighandlowsounds,LM1875amplifiercircuitandpowersupplycircuit.Amongthem,thesoundqualitycontrolpartusesanattenuatedtonecircuitcontrolledseparatelyforhighandlowsounds.Thespecificcomponentsareasfollows:R02,R03,C02,C01,W02formabasscontrolcircuit;C03,C04,W03formatreblecontrolcircuit;R04istheisolationresistance;W01isthevolumecontroller,whichadjuststhevolumeoftheamplifier;C05isanisolationcapacitortopreventthedownstreamLM1875DCpotentialelementfromaffectingtheprevioustonecircuit.TheamplifyingcircuitmainlyadoptsLM1875,whichiscomposedof1875,R08,R09,C066,etc.ThemagnificationofthecircuitisdeterminedbytheratioofR08toR09;C06isusedtostabilizethedriftoftheLM1875s4thpinDCzeropotential,butithasacertainimpactonthesoundquality;C07andR10functiontopreventtheamplifierfromgeneratinglow-frequencyself-excitation.InAddtion,theloadimpedanceofthisamplifieris416.Figure2.LM1875CircuitWhataboutthepowersupplycircuitofthepoweramplifier?Pleasetakealookatthepicturebelow.Inordertoensurethesoundqualityofthepoweramplifierboard,weneedtopayattentiontothefollowingwhendesigningthecircuit:Theoutputpowerofthepowertransformershallnotbelessthan80W;Theoutputvoltageis2*25V;Thefiltercapacitorusestwo4700UF/25Velectrolyticcapacitorsinparallel;Positiveandnegativepowersuppliesshare44700UF/25Vcapacitors;Thetwo104basecapacitorsarehigh-frequencyfiltercapacitors;Onlyiftheaboverequirementsaremet,theamplifiercanmaintainbettersoundquality.Figure3.LM1875CircuitIVLM1875CircuitAssemblyandDebuggingThisblogwillintroducethenecessarytoolsforcircuitassembly,howtoprepareforsoldering,andfinallyhowtodebugthecircuit.Ofcourse,ifyoustillfeellikeyouarestillcannotgetenough,intheendyoucanevenfollowourtipstotryanextrainterestingexperimentwiththiscircuit.ToolsThatYouNeedA20Welectricsolderingiron,preferablywithadjustabletemperature;Amultimeter;Apairofneedlenosepliers;Ascrewdriver;Somesolderwireandpineperfume.HowtoPrepareforWeldingWeldingsequence:①Weldingjumpers;②Weldingresistance;③Weldingcapacitor;④Weldedrectifiertube;⑤Weldingpotentiometer;⑥WeldLM1875.NotesFixtheLM1875withscrewsontheheatsinkbeforeweldingLM1875,otherwisethescrewswillbedifficulttodriveinwhentheheatsinkisinstalledattheend;ThepartofLM1875incontactwiththeheatsinkmustbecoatedwithasmallamountofheatdissipationgreasetofacilitateheatdissipation;Payattentiontotheweldingqualitywhenwelding.Forbeginners,youcanpracticeafewmoretimesontheoldcircuitboard,andthenformallysolder.HowtoDebugCorrectlyThedebuggingofthispoweramplifierboardisverysimple.Afterthecircuitboardissolderedwithelectroniccomponents,wemustcarefullycheckthecircuitboardforsolderingerrors.Specialattentionshouldbepaidtoelectronicpartswithpolarity,suchaselectrolyticcapacitorsandbridgerectifiers.Oncetheweldingisreversed,thereisariskofburningthecomponents.Whenthetransformerisconnected,theoutputterminaloftheamplifierisnotconnectedtothespeaker,butconnectedtoamultimeter(preferablydigitaldisplay,andthemultimeterissettoDC*2V).Inaddition,payattentiontothereadingofthemultimeterwhenpoweringonthepoweramplifierboard.Undernormalcircumstances,thereadingshouldbewithin30mV,otherwiseweshouldimmediatelycutoffthepowertocheckthecircuitboard.Ifthereadingoftheelectricmeteriswithinthenormalrange,itindicatesthatthefunctionofthepoweramplifierboardisbasicallynormal.Atthistime,weconnectedthespeaker,theninputthemusicsignal,andthenpoweronthetestmachine.Underthecorrectproceduresandspecifications,turnthevolumepotentiometer,thevolumeshouldchange,andturnthehighandlowknobs,thetoneofthespeakerwillchange.Figure4.LM1875ExperimentWorthTryingFirst,wewillshort-circuitC6andmeasuretheDCpotentialattheoutputofLM1875withamultimetertoseeifitiswithin30MV.Then,connectthespeakerandtestfortwohours.UseamultimetertomeasuretheDCpotentialattheoutputoftheLM1875toseeiftheDCpotentialiswithin30MV.IftheDCpotentialiswithin30MV,thecapacitorC6canbeomitted.Inthiscase,theamplifierboardbecomesapureDCpoweramplifier.VIntheEndSofar,thepoweramplifierboardhasbeensuccessfullyinstalledandadjusted.Lookingatthispieceofworkthatyoucanbeproudofandenjoyingthewonderfulmusic,areyousatisfied?IDescriptionThisblogintroducesthedesignofalithiumbatterybackuppowercontrolboardbasedonLM393,whichissimple,stable,reliable,andlow-cost.Itcandirectlyoutputthemainsvoltagewhenthereismainspower,andcontinuouslymonitorthemainsvoltage.Notonlycanthisdesignautomaticallyturnontheinverterwithin10msafterthemainspowerisoff,butitalsohasapowermanagementfunction:whentheinternallithiumbatteryvoltageislowerthanthesetvalue,itwillautomaticallycharge.ThisVediointroducesHowDoesLM393WorksCatalogIDescriptionIIDesignandWorkingPrinciple2.1Design2.2WorkingPrincipleIIITestIVConclsionOrdering&QuantityIIDesignandWorkingPrincipleThedetailsofLM393basedlithiumbatterybackupcircuitareasfollows:2.1Design2.1.1MainsPowerFailureWhenthereisnomainspowerinput,thecontrolpanelwillturnontheinverterandoutput220VACwithin10msofthemainspowerfailure.2.1.2ChargingManagementFigure1.FunctionDiagramWhenthereismainsinput,thecontrolboardfirstshutsdowntheinverteroutputandswitchestothemainsoutput;thenentersthechargingmanagementstate(duetothefeatureofthelithiumbatteryprotectionboard,theprotectionboardstopschargingafteroverchargeprotection.WhenthebatteryvoltageWhenitdropstotheoverchargerecoveryvalueorbelow,itwillautomaticallyresumecharging.Whenthereismainsinputforalongtime,thelithiumbatterychargerwillberepeatedlycharged,whichwillaffectthelifeofthelithiumbattery).Whenthelithiumbatteryisfullycharged,itwillstopcharging.Whenitdropstoacertainlevel(thisparameterislowerthantheoverchargerecoveryvalueofthelithiumbatteryprotectionboard,thespecificparametervalueisadjustable)andthenresumecharginguntilitisfullycharged,andrepeattheaboveprocess.2.2WorkingPrincipleAccordingtothedesignrequirements,theprincipledesignofthiscontrolboardisdividedintotwoparts:lithiumbatteryvoltagedetectionandcontrol,andmainsvoltagedetectionandcontrol.ThemainvoltagecomparisonpartofthecontrolboardusesthedualvoltagecomparatorintegratedchipLM393.LM393integrates2independentcomparators,itsoperatingpowersupplyvoltagerangeiswide,itcanworkfor2~36Vwhensinglepowerinput,and1~18Vwhendualpowerinput.Inaddition,itscurrentconsumptionissmall,only0.8mA.AndwhatisthepinoutofLM393?WecantakealookatFigure2below:Pins3,5arethenon-invertinginputterminalsofthetwocomparatorsrespectively;Pins2,6aretheinvertinginputterminalsofthetwocomparatorsrespectively;Pins1,7arethecorrespondingoutputterminalsofthetwocomparatorsrespectively.Figure2.LM393PinoutWhenusedasabasiccomparisoncircuit,ifthevoltageatthenon-invertinginputterminalisgreaterthanthevoltageattheinvertinginputterminal,thecorrespondingoutputterminaloutputsahighlevel,andviceversa.Forexample,whenU5U6,U7outputshighlevel;whenU5U6,U7outputslowlevel.2.2.1LithiumBatteryVoltageDetectionandControlLithiumbatteryvoltagedetectioncontrolisshowninFigure3.(1)PowerSupplyThepowersupplyofthecontrolpartistakenfromthelithiumbatteryofthebackuppowersupply,andthevoltageofthecontrolboardis12VDC.Becausethelithiumbatteryinthisdesignis48V,itsvoltagerangeis32Vto54.6V,whichishigherthanthelargeinputvoltagerequiredbythestabilizerblock7812.Therefore,inordertoprotectthevoltageregulatorblock7812,weneedtoconnecta20Vvoltageregulatortubeinseriesattheinputtostepdown.Here,diodeD5actsasreversevoltageprotection(2)VoltageComparisonThepowermanagementadoptsthecomparatorLM393,thesamplingvoltageofthelithiumbatteryisdividedbyresistorsR11andR12,andtheninputtothenon-invertinginputofLM393.Thereferencevoltagedivides12VthroughtheresistorR4andthepotentiometer,andthenenterstheinvertinginputofLM393.WhenthesamplingvoltageU1ishigherthanthereferencevoltageU2,theoutputterminalcorrespondingtoLM393outputsahighlevel,thetransistor9012isturnedoff,therelaydoesnotoperate,andtheinverterstopsworking.WhenthesamplingvoltageU1islowerthanthereferencevoltageU2,theoutputterminalcorrespondingtoLM393outputsalowlevel,thetransistor9012isturnedon,therelayacts,andtheinverteristurnedon.ThereferencevoltagecanbeadjustedaccordingtotheactualparametersthroughthepotentiometerR5.Figure3.LM393LithiumBatteryVoltageDetectionandControl(3)HysteresisComparatorCircuitInasingle-limitcomparator,iftheinputsignalUinhasaslightinterferencenearthethreshold,theoutputvoltagewillproducecorrespondingjitter(fluctuation).Forexample,inthedesignoflithiumbatteryvoltagedetection,ifthesamplingvoltageofthelithiumbatteryfluctuatesnearthetargetvoltage(seeFigure3),thevoltageofU1ishigherthanthevoltageofU2,andtheoutputofthecomparatorshouldoutputahighlevel.However,iftheU1voltageorU2voltagefluctuatesslightlyatthistime,thetransistor9012islikelytobeturnedonandofffrequentlyatthistime,andthecontroloutputwillbeveryunstable.Thenhowtoovercomethisshortcoming?Wecanintroducepositivefeedbackinthedesign(thatis,thewayofhardwaretoachievereturndifference).Ifweneedtofixatrippointatacertainreferencevoltagevalue,wecaninsertanon-linearelement(suchasacrystaldiode)inthepositivefeedbackcircuit.Byusingtheunidirectionalconductivityofthediode(inFigure2,D10diode1N4148),theaboverequirementscanbeachieved.2.2.2MainsVoltageDetectionandControlThedescriptionofthemainsvoltagedetectioncontrolpartisshowninFigure4.(1)PowerSupplyPartThepowersupplypartusesthesamepowersupplyDC12Vasthelithiumbatteryvoltagedetectionandcontrolpart.(2)MainsVoltageDetectionTakingintoaccountthecostofthemainsvoltagedetectionpart,thisdesignabandonsthetraditionaltransformerorvoltagetransformerdetectionmethod,andusestwooptocouplerchipsPC817todetectthemains.PC817isacommonlyusedlinearoptocoupler,whichisoftenusedinfunctionalcircuitsthatrequiremoreprecision.Whenanelectricalsignalisappliedtotheinputend,thelightemitteremitslightandilluminatesthelightreceiver.Thelightreceiveristurnedonafterreceivingthelight,andgeneratesaphotocurrentoutputfromtheoutputend,thusrealizingtheelectricity-optical-electricityconversion.Thisconversionisoftenappliedtovariouscivilindustrialproductssuchasswitchingpowersupplies,UPS,adapters,etc.Figure4.LM393MainsVoltageDetectionandControlTakeAC220Vasanexample.Inordertoprotecttheoptocoupler,weusea1Mresistorinthedesigntolimitthecurrentoftheoptocoupleremitter.TheoptocouplerchipsU1andU2arerespectivelyturnedonundertheactionofalternatingcurrent,andcooperatewiththecapacitorC6toensurethatthevoltageofthenon-invertinginputterminalU3isgreaterthantheinvertinginputterminalU4undertheconditionofnormalmainsinput.Theoptocouplerchipusedinthisdesigncanalsobeusedforelectricalisolationbetweenthecontrolboardandthemains.Whenthereismainspower:LM393snon-invertinginputterminalU3voltageisDC12VInvertinginputterminalU4voltageis9V(R2,R10dividedvoltage)ThecorrespondingoutputterminalishighThetransistor9014isturnedonTherelayoperatesThenormallyclosedpointisopenThereisoutputbetweenmainsvoltageWhenthereisnomainspower:Thevoltageatthenon-invertinginputterminalU3ofLM393isDC0VThevoltageattheinvertinginputterminalU4is9VThecorrespondingoutputterminalislowlevelThetransistor9014iscutoffTherelaydoesnotoperateThenormallyclosedpointisclosedTheinverteroutputs220V.IIITestAftertesting,thiscontrolcircuitmeetsthedesignrequirements:whenthereismainspowersupply,itoutputsmainsvoltage,andautomaticallyconvertstobackuppowersupplywithin10msinthecaseofmainspowerfailure,andhasgoodchargingmanagementfunctions,asshowninFigure5andFigure6.Figure5.LithiumBatteryVoltageDetectionWaveformFigure6.MainsVoltageDetectionWaveformInpracticalapplications,MOStubesandtriacscanalsobeusedtoreplacetherelaysinthevoltagedetectionandcontrolpartofthelithiumbatteryandtherelaysinthemainsvoltagedetectionandcontrolparttoachievethecontroloutput.IVConclsionThiscontrolboardisdesignedaccordingtothecharacteristicsofthelithiumbatterybackuppowersupplythatisgraduallypopularizedatpresent.Ithastheadvantagesofstronganti-interferenceandlowcost,andhasstrongmarketpromotionvalue.Insubsequentdesigns,wecanalsoaddprotectionfunctionssuchasbatteryunder-voltageprotection,short-circuitprotection,overloadprotection,over-voltageprotection,andover-temperatureprotectionaccordingtouserrequirementstocontinuouslyimprovetheproduct.Afterreadingtheblog,haveyoubetterunderstandLM393?Finally,ifyouhaveanyquestionsaboutLM393,pleasedonothesitatetoleaveamessageinthecommentsectionbelow!

LMG1020

IntroductionInordertosolvetheproblemoftransientdistortion,thetypicalapplicationcircuitofLM3886poweramplifierischangedtothecurrentnegativefeedbacktype.Thecurrentsampleflowingthroughthespeakervoicecoilisfedbacktothepoweramplifierinputterminalviaresistance,andtheloudspeakersystemisalsoincludedinthefeedbacksystem.CatalogIntroductionCatalogITypicalpoweramplifiercircuitIIImprovedPowerAmplifierCircuitOrdering&QuantityITypicalpoweramplifiercircuitThepoweramplifiercircuitmadeofLM3886consistsoftwoparts:pre-amplifierandpoweramplifier.ThepreamplifierconsistsofanintegratedoperationalamplifierNE5534,whichprovidesavoltagegainofabout5times.ThepoweramplifieriscomposedofLM3886,whichprovidesavoltagegainofabout10times.Therefore,thefullpoweroutputcanbeachievedbyinputtingabout0.5Vsignalattheinputend.Figure1onlyshowstheLM3886dualpowersupplycircuit,whichcanalsoworkinasinglepowersupply.Consideringfromtheaspectofsoundquality,theaudioamplifiercircuitgenerallydoesnotusesinglepowersupply,butdualpowersupply.Figure1.typicalpoweramplifiercircuitThetypicalapplicationcircuitofLM3886adoptsthetraditionalnegativevoltagefeedbackmode.Negativevoltagefeedbackcanimprovethefrequencycharacteristicsofpoweramplifierandreducenonlineardistortion,butthesoundislackofstrength.Asthevolumeincreases,thelowfrequencywillbecometight,dryandhard,andthedistortionwillincrease.Atthesametime,thehighfrequencybecomessharpandharsh,andthemusicanditsdefinitionaregreatlyreduced.Thisistheso-calledTransientIntermodulationDistortion.Thetransientintermodulationdistortionismainlycausedbytheintroductionofdeepnegativefeedback.Voltagetypenegativefeedbackiseffectivetoimprovethenonlineardistortionofpoweramplifier,butitcannottakeintoaccountthetransientdistortionatthesametime.IIImprovedPowerAmplifierCircuitTheimprovedcircuitisshowninFigure2.Thelow-frequencyspectralgainofpoweramplifierisdeterminedbytheratioofR3andR4.C3andR5determinethehigh-frequencygainofpoweramplifier.DuetothelargecapacitancereactanceofC3atlowfrequency,thecurrentfeedbackisterminatedatlowfrequency,whilethehighfrequencyisimprovedbycurrentnegativefeedback.Theresultisthatthetotalbandwidthisimprovedandthetransientdistortionisgreatlyreduced.Theselectionoffeedbackcomponentsshouldbebasedontheimpedanceandinductanceoftheloudspeaker,sothatthelow-frequencygainis2-3timesofthehigh-frequencygain.Formerpoweramplifiersoftendesignedthefrequencycharacteristicstobeflat,whichdidnotachievegoodsoundeffects.Inordertoimprovethesoundeffectofthepoweramplifier,weshouldusethenegativefeedbackcircuittoconsciouslyincreasethelowfrequencygaintoachievethebesteffect,whichalsomeetstherequirementsofthelargedynamicsoundeffectoftodayshometheater.Figure2.schematicdiagramofpoweramplifiercircuitThesoundeffectofthismachineisexcellent.Thelowfrequencyextensionisincreasedanditisflexible.Thehighfrequencyisclearandsmooth.Theresolutionisgreatlyimproved,andthemetallicsoundiscompletelydisappeared.Evenifthevolumewasdoubled,nosignificantdistortionwasheard.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)0to70NumberofTerminals11NumberofFunctions1BrandNameT