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IDescriptionThisblogusesLM386integratedblockasthecoredevicetomakeasimplesoundamplifier.Itsproductioncostisrelativelylow.Thisblogissuitableforbeginnerstolearnaboutpowertubes,integratedoperationalamplifiers,speakers,languagechipsandothercomponents.Sowecanmastertheprinciples,characteristicsandusageofthebasicamplifiercircuitandpoweramplifiercircuit.Figure1.LM386CatalogIDescriptionIIIntroductiontoLM3862.1Features2.2InternalStructureIIIWorkingPrincipleofLM386SoundAmplifierIVLM386SoundAmplifierDebuggingVConclusionFAQOrdering&QuantityIIIntroductiontoLM3862.1FeaturesLM386isakindofaudiointegratedamplifier.Ithastheadvantagesoflowpowerconsumption,adjustableinternalchaingainadjustment,largepowersupplyvoltagerange,fewexternalcomponentsandlowtotalharmonicdistortion.Therefore,LM386iswidelyusedinrecordersandradios,mainlyinlow-voltageconsumerproducts.LM386featuresare:BatteryOperationMinimumExternalPartsWideSupplyVoltageRange:4V12Vor5V18VLowQuiescentCurrentDrain:4mAVoltageGainsfrom20to200Ground-ReferencedInputSelf-CenteringOutputQuiescentVoltageLowDistortion:0.2%(AV=20,VS=6V,RL=8,PO=125mW,f=1kHz)Availablein8-PinMSOPPackageBasedonthecharacteristicsshownabove,lm386componentsarewidelyusedincommunicationequipment,smallradios,andwalkie-talkiecircuits.Itisalsocalleduniversalpoweramplifiercircuitbythemajorityofelectronicenthusiasts.2.2InternalStructureLM386adopts8-pindualin-linepackage.SeeFigure2forthepinarrangementdiagram.Figure2.LM386PinArrangementPin6isconnectedtothepositivepoleofthepowersupply;Pin4aregrounded;Pin2invertinginputterminal;Pin3non-invertinginputterminal;Pin5istheoutputterminal;Pins1,7,and8areusedtoimprovetheperformanceofthecircuit.Theexternalcomponentends,andtheinternalcircuitisathree-stageamplifiercircuit:The1ststageconsistsofVT1~VT6toformadifferentialamplifiercircuit,The2ndstageiscomposedofVT7voltageamplifiercircuit,The3rdstageiscomposedofVT8~VT10toformacomplementarysymmetricalOTLoutputcircuitthatcaneliminatecrossoverdistortion.R5,R6,andR7formanegativefeedbacknetwork.IIIWorkingPrincipleofLM386SoundAmplifierThecoreoftheLM386soundamplifieristheLM386poweramplifierintegratedcircuit.AsshowninFigure3.TheelectretmicrophoneB1convertssoundsignalsintoelectricalsignals.Thissignalisveryweak,howtoamplifyit?WecanaddthecouplingcapacitorC1tothebaseofVT1,andVT1formsacommonemitteramplifiercircuittoamplifythesignal.Also,thesignalisoutputfromthecollectorofVT1,andaddedtotheinvertinginputterminalofLM386viacouplingcapacitorC2topin2andpin3isgrounded.AfterthesignalisamplifiedbytheinternalthreestagesofLM386,thesignalisoutputfrompin5,andthenpassesthroughthecouplingcapacitor.C3issenttothespeakers.Aftergoingthroughtheseprocesses,itcanmakeasound.Figure3.LM386SoundAmplifierFigure4.LM386AudioAmplifierCircuitThenhowtoadjustthesignalmagnificationofLM386?Here,wecanconnectanadjustableresistorR5andcapacitorC6topin1andpin8toformaseriesRCnetwork.WhenR5=0,thevoltagemagnificationis200.Pin7isconnectedtocapacitorC5topreventLM386fromgeneratingself-excitation.Inaddition,pin5isgroundedthroughR4andC4tomakethespeakersoundsofter.IVLM386SoundAmplifierDebuggingAfterthecircuitisassembled,weshouldcarefullycheckforerrorsorfalsesoldering.Ifthereisnoabnormalityaftertheinspection,turnonthe6Vpowersupplyfordebugging:Step1:Dontpickupthemicrophonefirst.Whenthereisnoinputsignal,testthequiescentcurrentofthewholemachine,whichisabout7mA.Step2:TestthestaticvoltagevalueofeachpinofLM386,asshowninFigure2.Step3:Afterthevoltageandcurrentarenormal,placetheRPvolumeregulatorinthemiddleandtouchthebaseofVT1withascrewdriver.Thespeakerwillemitaclickclicksound,indicatingthatthecircuitisnormal.Step4:ConnectthemicrophoneB1,andthenfine-tunetheRP.Ifnothinggoeswrong,speakintothemicrophone,thespeakershouldhaveamplifiedsound.Ifthereisnosound,checkwhetherthemicrophonecableisconnectedincorrectlyorthequalityofthemicrophoneisdefective.Step5:Whenusingasoundamplifier,donotplacethemicrophoneandspeakertooclosetogether.Iftheyareunfortunatelytooclose,thespeakerswillmakeaharshsound.Therefore,itisbesttouseshieldedwireforthemicrophonelead-out.Figure5.LM386VConclusionThroughthedesignofthisblog,wehaveanessentialunderstandingoftheworkingprincipleofLM386.Wehavemasteredthepinfunction,internalstructurecircuitandworkingprincipleofLM386.Inaddition,thesoundamplifiermadebyLM386hasthecharacteristicsofsimplecircuit,convenientdebugging,andcompletefunctions.Afterreadingthisblog,haveyoubetterunderstandLM386?FAQHowdoesanLM386work?TheLm386integratedchipisalowpoweraudiofrequencyamplifier,whichuseslowlevelpowersupplylikebatteriesinelectroniccircuits.Itisdesignedas8pinminiDIPpackage.Thisprovidesvoltageamplificationof20.Byusingexternalpartsvoltagegaincanberaisedupto200.Islm386anopamp?TheLM386isatypeofoperationalamplifier(Op-Amp)....Inanamplifiercircuit,theLM386takesanaudioinputsignalandincreasesitspotentialanywherefrom20to200times.Thatamplificationiswhatsknownasthevoltagegain.Whatislm386IC?TheLM386isanintegratedcircuitcontainingalowvoltageaudiopoweramplifier.Itissuitableforbattery-powereddevicessuchasradios,guitaramplifiers,andhobbyelectronicsprojects.Howdoyoucalculatelm386gain?VoltageGainAnalysis:Withoutanyexternalcomponents,ithasagainofGv=2x15K/(150+1350)=20(26dB).Withacapacitor(orshortcutting)betweenpins1and8,ithasagainofGv=2x15K/150=200(46dB).WhichICisusedinaudioamplifier?TheICLM386isalow-poweraudioamplifier,anditutilizeslowpowersupplylikebatteriesinelectricalandelectroniccircuits.ThisICisavailableinthepackageofmini8-pinDIP.WhataresomeprojectsthatusetheLM386audioamplifiercircuit?LM386isanintegratedclassABampandisgoodforbeginnerssmallaudioamplifierapplicationsforexampleinaRFreceiver,smallStereosystem,cheaplowvoltageamplifieretcdrawbacksisthatitcannothandlemuchpowerandhencecreatesdistortionwhenyoucrankupthevolumetoomuch..SootherICsareusedinpractical.HowtomakeanLM386audioamplifiercircuit?

IDescriptionThisblogusesLM386integratedblockasthecoredevicetomakeasimplesoundamplifier.Itsproductioncostisrelativelylow.Thisblogissuitableforbeginnerstolearnaboutpowertubes,integratedoperationalamplifiers,speakers,languagechipsandothercomponents.Sowecanmastertheprinciples,characteristicsandusageofthebasicamplifiercircuitandpoweramplifiercircuit.Figure1.LM386CatalogIDescriptionIIIntroductiontoLM3862.1Features2.2InternalStructureIIIWorkingPrincipleofLM386SoundAmplifierIVLM386SoundAmplifierDebuggingVConclusionFAQOrdering&QuantityIIIntroductiontoLM3862.1FeaturesLM386isakindofaudiointegratedamplifier.Ithastheadvantagesoflowpowerconsumption,adjustableinternalchaingainadjustment,largepowersupplyvoltagerange,fewexternalcomponentsandlowtotalharmonicdistortion.Therefore,LM386iswidelyusedinrecordersandradios,mainlyinlow-voltageconsumerproducts.LM386featuresare:BatteryOperationMinimumExternalPartsWideSupplyVoltageRange:4V12Vor5V18VLowQuiescentCurrentDrain:4mAVoltageGainsfrom20to200Ground-ReferencedInputSelf-CenteringOutputQuiescentVoltageLowDistortion:0.2%(AV=20,VS=6V,RL=8,PO=125mW,f=1kHz)Availablein8-PinMSOPPackageBasedonthecharacteristicsshownabove,lm386componentsarewidelyusedincommunicationequipment,smallradios,andwalkie-talkiecircuits.Itisalsocalleduniversalpoweramplifiercircuitbythemajorityofelectronicenthusiasts.2.2InternalStructureLM386adopts8-pindualin-linepackage.SeeFigure2forthepinarrangementdiagram.Figure2.LM386PinArrangementPin6isconnectedtothepositivepoleofthepowersupply;Pin4aregrounded;Pin2invertinginputterminal;Pin3non-invertinginputterminal;Pin5istheoutputterminal;Pins1,7,and8areusedtoimprovetheperformanceofthecircuit.Theexternalcomponentends,andtheinternalcircuitisathree-stageamplifiercircuit:The1ststageconsistsofVT1~VT6toformadifferentialamplifiercircuit,The2ndstageiscomposedofVT7voltageamplifiercircuit,The3rdstageiscomposedofVT8~VT10toformacomplementarysymmetricalOTLoutputcircuitthatcaneliminatecrossoverdistortion.R5,R6,andR7formanegativefeedbacknetwork.IIIWorkingPrincipleofLM386SoundAmplifierThecoreoftheLM386soundamplifieristheLM386poweramplifierintegratedcircuit.AsshowninFigure3.TheelectretmicrophoneB1convertssoundsignalsintoelectricalsignals.Thissignalisveryweak,howtoamplifyit?WecanaddthecouplingcapacitorC1tothebaseofVT1,andVT1formsacommonemitteramplifiercircuittoamplifythesignal.Also,thesignalisoutputfromthecollectorofVT1,andaddedtotheinvertinginputterminalofLM386viacouplingcapacitorC2topin2andpin3isgrounded.AfterthesignalisamplifiedbytheinternalthreestagesofLM386,thesignalisoutputfrompin5,andthenpassesthroughthecouplingcapacitor.C3issenttothespeakers.Aftergoingthroughtheseprocesses,itcanmakeasound.Figure3.LM386SoundAmplifierFigure4.LM386AudioAmplifierCircuitThenhowtoadjustthesignalmagnificationofLM386?Here,wecanconnectanadjustableresistorR5andcapacitorC6topin1andpin8toformaseriesRCnetwork.WhenR5=0,thevoltagemagnificationis200.Pin7isconnectedtocapacitorC5topreventLM386fromgeneratingself-excitation.Inaddition,pin5isgroundedthroughR4andC4tomakethespeakersoundsofter.IVLM386SoundAmplifierDebuggingAfterthecircuitisassembled,weshouldcarefullycheckforerrorsorfalsesoldering.Ifthereisnoabnormalityaftertheinspection,turnonthe6Vpowersupplyfordebugging:Step1:Dontpickupthemicrophonefirst.Whenthereisnoinputsignal,testthequiescentcurrentofthewholemachine,whichisabout7mA.Step2:TestthestaticvoltagevalueofeachpinofLM386,asshowninFigure2.Step3:Afterthevoltageandcurrentarenormal,placetheRPvolumeregulatorinthemiddleandtouchthebaseofVT1withascrewdriver.Thespeakerwillemitaclickclicksound,indicatingthatthecircuitisnormal.Step4:ConnectthemicrophoneB1,andthenfine-tunetheRP.Ifnothinggoeswrong,speakintothemicrophone,thespeakershouldhaveamplifiedsound.Ifthereisnosound,checkwhetherthemicrophonecableisconnectedincorrectlyorthequalityofthemicrophoneisdefective.Step5:Whenusingasoundamplifier,donotplacethemicrophoneandspeakertooclosetogether.Iftheyareunfortunatelytooclose,thespeakerswillmakeaharshsound.Therefore,itisbesttouseshieldedwireforthemicrophonelead-out.Figure5.LM386VConclusionThroughthedesignofthisblog,wehaveanessentialunderstandingoftheworkingprincipleofLM386.Wehavemasteredthepinfunction,internalstructurecircuitandworkingprincipleofLM386.Inaddition,thesoundamplifiermadebyLM386hasthecharacteristicsofsimplecircuit,convenientdebugging,andcompletefunctions.Afterreadingthisblog,haveyoubetterunderstandLM386?FAQHowdoesanLM386work?TheLm386integratedchipisalowpoweraudiofrequencyamplifier,whichuseslowlevelpowersupplylikebatteriesinelectroniccircuits.Itisdesignedas8pinminiDIPpackage.Thisprovidesvoltageamplificationof20.Byusingexternalpartsvoltagegaincanberaisedupto200.Islm386anopamp?TheLM386isatypeofoperationalamplifier(Op-Amp)....Inanamplifiercircuit,theLM386takesanaudioinputsignalandincreasesitspotentialanywherefrom20to200times.Thatamplificationiswhatsknownasthevoltagegain.Whatislm386IC?TheLM386isanintegratedcircuitcontainingalowvoltageaudiopoweramplifier.Itissuitableforbattery-powereddevicessuchasradios,guitaramplifiers,andhobbyelectronicsprojects.Howdoyoucalculatelm386gain?VoltageGainAnalysis:Withoutanyexternalcomponents,ithasagainofGv=2x15K/(150+1350)=20(26dB).Withacapacitor(orshortcutting)betweenpins1and8,ithasagainofGv=2x15K/150=200(46dB).WhichICisusedinaudioamplifier?TheICLM386isalow-poweraudioamplifier,anditutilizeslowpowersupplylikebatteriesinelectricalandelectroniccircuits.ThisICisavailableinthepackageofmini8-pinDIP.WhataresomeprojectsthatusetheLM386audioamplifiercircuit?LM386isanintegratedclassABampandisgoodforbeginnerssmallaudioamplifierapplicationsforexampleinaRFreceiver,smallStereosystem,cheaplowvoltageamplifieretcdrawbacksisthatitcannothandlemuchpowerandhencecreatesdistortionwhenyoucrankupthevolumetoomuch..SootherICsareusedinpractical.HowtomakeanLM386audioamplifiercircuit?

IntroductionTheCD4066isaquadbilateralswitchwhichcanbeappliedforswitchingofanalogsignalsanddigitalsignals.Itconsistsoffourindependentanalogswitches,eachwiththreeterminals:input,outputandcontrol.Whenthecontrolterminalisappliedwithhighpowerlevel,theswitchison.Whenthecontrolterminalisaddedwithlowpowerlevel,theswitchisclosed.Theinputterminalandoutputterminalcanbeusedinterchangeably.Thisconfigurationeliminatesthevariationoftheswitch-transistorthresholdvoltagewithinputsignaland,thus,keepstheon-stateresistancelowoverthefulloperating-signalrange.Theadvantagesoversingle-channelswitchesincludepeakinput-signalvoltageswingsequaltothefullsupplyvoltageandmoreconstanton-stateimpedanceovertheinput-signalrange.ThisarticleintroducestwoapplicationexamplesofCD4066analogswitch.CatalogIntroductionCatalogITrack-and-HoldCircuitofSignalIIInterchangingDisplayCircuitofFourWaysofElectronicSignalFAQOrdering&QuantityITrack-and-HoldCircuitofSignalFigure1.Track-and-HoldCircuitofSignalTheanalogsignalUiisfromthein-phaseinputoftheoperationalamplifier.Whenthecontrolterminaloftheanalogswitchisathighlevel,theanalogswitchison,andthecapacitorCischargedtoUi.Thisprocessiscalledthesamplingoftheinputsignal.Whenthesamplingisover,thecontrolterminaloftheanalogswitchislowlevelandtheanalogswitchisoff.Becausetheresistanceisashighas100Mwhentheanalogswitchisoff,andtheinputimpedanceofoperationalamplifierA2isalsoveryhigh,thesamplingsignalcanbemaintainedonthecapacitorC.IIInterchangingDisplayCircuitofFourWaysofElectronicSignalAgeneralsinglelineoscilloscopecanonlydisplayonecontinuoussignal.Butthisdevicecandisplayfourcontinuoussignalssimultaneouslyinasinglelineoscilloscope.Itisveryconvenienttocomparethetimerelationofdifferentsignals.Figure2.InterchangingDisplayCircuitofFourWaysofElectronicSignalFigure2isthecircuitdiagramofthedevice.ItusesaCD4017counterandoscillatortoformafour-beatcircuittocontrolthefouranalogswitchesintwoCD4066.AdjustableDClevelandoneinputsignalareaddedrespectivelyoneachpairofanalogswitches.Whenthecontrolendoftheanalogswitchishighlevel1,theanalogswitchison.TheDClevelandinputsignalaresenttothey-axisinputendoftheoscilloscope.BecausethefoursignalscorrespondtodifferentDClevels,thefoursignalsdisplayseparatelyontheoscilloscope.AlthoughthefourpairsofanalogswitchesarecontrolledbythecountersQ0,Q1,Q2,Q3outputterminal,theflickerofthewaveformissmallduetothehighoscillationfrequencyoftheoscillator.FAQWhatisCD4066?TheCD4066isaQuadBilateralSwitchIC,thatis,ithasfourswitcheswhichcanbecontrolledindividualusingacontrolpin.Theseswitchescanconductinboththedirectionsmakingitbilateral,itiscommonlyusedformultiplexinganalogordigitalsignals.HowtouseCD4066?TheCD4066ICconsistsoffourswitches.Itcanswitchanalogsignalsthroughdigitalcontrol.Ananalogsignalisappliedattheinputoftheswitch.IfaHIGHor1valueisfedintothecontrolinput,theanalogsignalwillbepassedfrominputtotheoutputofaswitch.HowCD4066work?The4066reallyfunctionsasananalogswitch.The4066isanICcomposedofswitcheswhicharedesignedtoswitchanalogsignalsviadigitalcontrol....The4066isaquadbilateralswitchcircuit,meaningthatiscomposedof4switches.Eachswitchhasasingleinputandasingleoutputterminal.WhataretheapplicationsofCD4066?TheCD4066isabi-directionalanalogswitchingICsimilartoCD4016,itiscommonlyusedinmultiplexingapplications;itcanalsobeusedtoisolatesignals.Theswitchisbilateralandhencecanbeusedforbothdigitalandanalogsignals.WhatsthedifferencebetweenCD4016andCD4066?ThemajordifferencebetweenbothisthatCD4066hasverylowinternalresistance,accordingtothedatasheetitcanonly5ofon-stateresistanceascomparedwith200ofCD4016IC.IDescriptionIndailylife,calendarclocksareusedinvariousplaces.Suchasshoppingmalls,supermarkets,offices,homes,schools,etc.Comparedwiththetraditionalmechanicalclock,thedigitalcalendarclockhasaseriesofadvantages.Suchashighprecision,intuitivedisplay,andlonglife.ThisblogintroducesacalendarclockdesignedwithaDS1302rtcchip.DS1302RTCwithArduinoTutorialCatalogIDescriptionIISystemHardwareDesign2.1OverallStructure2.2DS1302ClockModule2.3LCD1602LCDModuleIIISystemSoftwareDesign3.1DesignofDS1302ClockSubprogram3.2LCD1602LiquidCrystalDisplaySubprogramDesignIVConclusionFAQOrdering&QuantityIISystemHardwareDesign2.1OverallStructureTakeAT89C51single-chipmicrocomputerasthemaincontroller,anduseDS1302clockchiptodesigncalendarclock.ItsoverallstructureisshowninFigure1.Figure1.OverallStructureofSystemThedesignedcalendarclockmustnotonlydisplayhours,minutesandseconds,butalsodisplayyears,months,daysandweeks.ThecoreofthesystemistheAT89C51microcontroller.Throughthesingle-chipcomputercontrolDS1302displaycalendarandtime.AndtheoutputresultisdisplayedonLCD1602liquidcrystalscreen.2.2DS1302ClockModuleTheDS1302clockchiphasthecharacteristicsoflowpowerconsumptionandhighperformance.Itcancommunicatewiththemicrocontrollerthroughasimplesynchronousserialmode,andonlyrequiresthreeI/Olines.Namelyreset(RST),I/Odatalineandserialclock(SCLK)2.2.1DS1302PinsandStructureFigure2showstheexternalpinsandfunctionsofDS1302.Figure2.DS1302PinoutVCC2-mainpowersupplypin;X1,X2-32.768kHzcrystaloscillatorpin;GND-ground;VCC1-batterypin;SCLK-serialclock;I/O-datainput/output;RST-reset.TheinternalstructureofDS1302isshowninFigure3,whichismainlycomposedofthefollowingparts:real-timeclock,datamemoryRAM,oscillatorcircuitandfrequencydivider,inputshiftregister,commandandcontrollogicandsoon.2.2.2DS1302RegistersandcontrolcommandsTheDS1302clockchiphas7registersrelatedtothecalendarclock,asshowninTable1.ThecommunicationsignalbetweenDS1302andsingle-chipmicrocomputerisrealizedthroughsimplesynchronousserialcommunication.AccordingtotheworkingtimingrequirementsofDS1302,whetherthesingle-chipmicrocomputerperformsreadoperationcommunicationfromDS1302orthesingle-chipcomputerperformswriteoperationcommunicationtoDS1302,eachcommunicationisinitiatedbythesingle-chipcomputerfirst.Inotherwords,beforeexecutingthecorrespondingreadorwriteoperation,themicrocontrollermustwriteabyteofcommandwordtoDS1302.Theeight-bitdataofthebytecommandwordisshowninFigure4.Figure4.CommandwordstructureofDS13022.3LCD1602LCDModuleTheLCD1602screencandisplaytwolinesofcharacters,16charactersperline,foratotalof32characters.Thereisan80*8-bitdisplaydatamemoryDDRAMbufferinLCD1602.SeeTable2forthecorrespondencebetweencharacterdisplaybitsandDDRAMaddress.TheaddressonthefirstlineofDDRAMstartsat00Handendsat27H.Theaddressesonthesecondlinestartat40Handendat67H,with40addressesperline.AndLCD1602displays16charactersperline.Therefore,whenwritingaprogram,selectthefirst16addressesofDDRAM.Itisimportanttonotethatthesecondlineaddressstartsfrom40H.IfyouwanttodisplayacharacterinacertainrowandcertaincolumnoftheLCD1602screen,writetheASCIIcodecorrespondingtothischaracterintothecorrespondingDDRAMaddressofacertainrowandcertaincolumn.Atthistime,youwillfindthatthecharactercannotbedisplayednormallyontheLCDscreen.Thereasonisthat80Hmustbeaddedtotheaddress.Forexample,todisplaythesymbolVinthesecondrowandsecondcolumnofthevoltageunitvolts,firstadd80HtothecorrespondingDDRAMaddress41Hinthesecondrowandsecondcolumn,thatis,C1H.ThenwritetheASCIIcode0x56correspondingtotheVcharacterintheC1Haddress.Onlythencanitbedisplayednormally.Thedisplayofothercharacterscanbededucedbyanalogyandwillnotberepeatedhere.IIISystemSoftwareDesignThesoftwareprogrammainlycompletesthefunctionsofdatareading,conversionandliquidcrystaldisplayofthecalendarclock.3.1DesignofDS1302ClockSubprogramsbitRST=P1^0;//DS1302resetportisdefinedinP1.0pinsbitSCLK=P1^1;//TheDS1302clockoutputportisdefinedontheP1.1pinsbitDATA=P1^2;//TheDS1302dataoutputportisdefinedontheP1.2pin(1)Theprogramthatthesingle-chipmicrocomputerwritesabyteofdatatoDS1302voidwright1302(unsignedchardate){Unsigneedchari;SCLK=0;//BepreparedfortherisingedgetowritedataDelaynus(2);for(i=0;i8;i++)//Writeeight-bitdatacontinuously{DATA=date0x01;//Writethebit0dataofdateintoDS1302Delaynus(2);SCLK=1;//WritedataonrisingedgeDelaynus(2);SCLK=0;//date=1;//moveoneplacetotheright}}(2)Theprogramforthesingle-chipmicrocomputertoreadabyteofdatafromDS1302unsignedcharreadd1302(void){Unsignedchari,date;Delaynus(2);for(i=0;i8;i++)//Continuouslyreadeight-bitdata{Date=1;//shiftonebittotherightif(DATA==1)//Ifthedatareadoutis1date|=0x80;//Takeout1andwriteitinthehighestbitofdateSCLK=1;//SetSCLKtoahighlevel,readoutforthefallingedgeDelaynus(2);SCLK=0;//PulldownSCLKtoformthefallingedgeofthepulseDelaynus(2);}returndate;//Returnthereaddata}3.2LCD1602LiquidCrystalDisplaySubprogramDesignThedriverprogramofLCD1602LCDscreenisrelativelycomplicatedtocompile,sowemustfigureouttheusageandmeaningofeachoperationinstructionof1602.Mainlyincludethefollowing:DisplaymodesettingDisplayswitchcontrolInputmodecontrolReaddatafromDDRAMWritedatatoDDRAMClearscreen,cursorhomesettingDataaddresspointersettingLCDscurrentbusyworksign...Partofthecodedesignisasfollows:voidLcd_initial()//InitializeLCD{E=0;Lcd_writecmd(0x38);//16*2display,5*7dotmatrixMsdelay(1);Lcd_writecmd(0x08);//displayoffMsdelay(2);Lcd_writecmd(0x01);//displayclearscreenMsdelay(2);Lcd_writecmd(0x06);//Setthecursor,afterreadingandwritingacharacter,thecursorincreasesby1Msdelay(1);Lcd_writecmd(0x0c);//displayison,nocursorisdisplayedMsdelay(1);}Figure5.HardwarepowersupplydiagramofDS1302calendarclockIntheMedwinV3.0developmentenvironment,useC51languagetocompilethesystemprogram,compileanddebug.AndloadtheHEXhexadecimalfilegeneratedbycompilingintotheMCUchip.StartthesimulationandyoucanseethesimulationrunningeffectoftheDS1302calendarclockdesignsystembasedon1602LCDdisplay.Forexample,thecurrenttimeis11:42:25onMay28,2019,andthesimulationresultisshowninFigure6.Figure6.SimulationresultsofcalendarclockItcanbeseenfromFigure6thatthecurrentdateandtimecanbedisplayedontheLCDscreeninrealtimeandaccurately.IVConclusionCalendarclocksareeverywhereinourlives.ThistexttakesAT89C51single-chipmicrocomputerasthemaincontroller,andusesDS1302real-timeclockchiptodesignthecalendarclocksystem.Inaddition,thehardwarecircuitwasdesignedintheProteussimulationsoftware,andthecorrespondingC51programwaswrittenintheMedwinV3.0developmentenvironment.Thejointuseofthesetwosoftwares,ProteusandMedWinV3.0,greatlyimprovestheefficiencyofsingle-chipsystemdesign,reducescosts,andshortensthedevelopmentcycle.FAQWhatisDS1302?DS1302isatickle-chargetimekeepingchipwhichcontainsareal-timeclock/calendarand31bytesofstaticRAM.DS1302usesserialcommunicationtointeractwithmicrocontrollers.Also,itautomaticallyadjustthedateforthemonthwithfewerdays.WhatdoesanRTCdo?Areal-timeclock(RTC)isacomputerclock(mostoftenintheformofanintegratedcircuit)thatkeepstrackofthecurrenttime.Althoughthetermoftenreferstothedevicesinpersonalcomputers,serversandembeddedsystems,RTCsarepresentinalmostanyelectronicdevicewhichneedstokeepaccuratetime.HowdoyouuseRTC?WiringItUp.5VisusedtopowertotheRTCchipwhenyouwanttoqueryitforthetime.Ifthereisno5Vsignal,thechipgoestosleepusingthecoincellforbackup.ConnectGNDtocommonpower/dataground.ConnecttheSCLpintotheI2CclockSCLpinonyourArduino....ConnecttheSDApintotheI2CdataSDApinonyourArduino.

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DescriptionDS1302isalow-powerreal-timeclockchipwithtricklecurrentchargingcapability.Itcantimetheyear,month,day,week,hour,minute,andsecond.ThisVideoIntroducesDS1302ArduinoRealtimeClockCatalogDescriptionDS1302PinoutDS1302DocumentsandMediaDS1302CADModelsDS1302ParametersDS1302FeaturesDS1302AdvantageDS1302ApplicationsDS1302TypicalOperatingCircuitDS1302EnvironmentalandExportClassificationsDS1302BlockDiagramHowtoUseDS1302DS1302RTCModuleDS1302CommandByteFAQOrdering&QuantityDS1302PinoutThefigurebelowshowsthepinarrangementofDS1302.Amongthem,Vcc2isthemainpowersupply,andVCC1isthebackuppowersupply.Thecontinuousoperationoftheclockcanbemaintainedevenwhenthemainpowerisoff.DS1302ispoweredbythelargerofVcc1orVcc2.WhenVcc2isgreaterthanVcc1+0.2V,Vcc2suppliespowertoDS1302.WhenVcc2islessthanVcc1,DS1302ispoweredbyVcc1.X1andX2aretheoscillationsourcesandanexternal32.768kHzcrystaloscillator.RSTisthereset/chipselectline.AlldatatransfersarestartedbydrivingtheRSTinputtohigh.RSTinputhastwofunctions:First,RSTturnsonthecontrollogic,allowingtheaddress/commandsequencetobesenttotheshiftregister;second,RSTprovidesamethodtoterminatesingle-byteormulti-bytedatatransmission.WhenRSTishigh,alldatatransfersareinitialized,allowingoperationsonDS1302.IfRSTissettoalowlevelduringthetransfer,thedatatransferwillbeterminatedandtheI/Opinwillbecomehighimpedance.Duringpower-onoperation,RSTmustremainlowbeforeVcc2.0V.OnlywhenSCLKislow,canRSTbesethigh.I/Oisaserialdatainputandoutputterminal(two-way),whichwillbedescribedindetaillater.SCLKistheclockinputterminal.PinNumberPinNameDescription1VCC2PrimaryPower-SupplyPininDualSupplyConfiguration.VCC1isconnectedtoabackupsourcetomaintainthetimeanddateintheabsenceofprimarypower.TheDS1302operatesfromthelargerofVCC1orVCC2.WhenVCC2isgreaterthanVCC1+0.2V,VCC2powerstheDS1302.WhenVCC2islessthanVCC1,VCC1powerstheDS1302.2X1ConnectionsforStandard32.768kHzQuartzCrystal.Theinternaloscillatorisdesignedforoperationwithacrystalhavingaspecifiedloadcapacitanceof6pF.Formoreinformationoncrystalselectionandcrystallayoutconsiderations,refertoApplicationNote58:CrystalConsiderationsforDallasReal-TimeClocks.TheDS1302canalsobedrivenbyanexternal32.768kHzoscillator.Inthisconfiguration,theX1pinisconnectedtotheexternaloscillatorsignalandtheX2pinisfloated.3X24GNDGround5CEInput.CEsignalmustbeassertedhighduringareadorawrite.Thispinhasaninternal40kΩ(typ)pulldownresistortoground.Note:PreviousdatasheetrevisionsreferredtoCEasRST.Thefunctionalityofthepinhasnotchanged.6I/OInput/Push-PullOutput.TheI/Opinisthebidirectionaldatapinforthe3-wireinterface.Thispinhasaninternal40kΩ(typ)pulldownresistortoground.7SCLKInput.SCLKisusedtosynchronizedatamovementontheserialinterface.Thispinhasaninternal40kΩ(typ)pulldownresistortoground.8VCC1Low-PowerOperationinSingleSupplyandBattery-OperatedSystemsandLowPowerBatteryBackup.Insystemsusingthetricklecharger,therechargeableenergysourceisconnectedtothispin.ULrecognizedtoensureagainstreversechargingcurrentwhenusedwithalithiumbattery.DS1302DocumentsandMediaDatasheetsDS1302OtherRelatedDocumentsTipsforWritingBulletproofReal-TimeClockControlCodeMfgApplicationNotesEstimatingSuperCapacitorBackupTimeonTrickle-ChargerReal-TimeClocksSelectingaBackupSourceforReal-TimeClocksOscillatorDesignConsiderationsforLow-CurrentApplicationsStateMachineLogicinBinary-CodedDecimal(BCD)-FormattedReal-TimeClocksEnvironmentalInformationHalogenCertificateRedPhosphorousCertificateMaterialDeclarationDS1302PCNObsolescence/EOLMultDevOBS15/Jul/2015HTMLDatasheetDS1302EDA/CADModelsDS1302bySnapEDADS1302byUltraLibrarianDS1302CADModelsDS1302SymbolDS1302FootprintDS1302ParametersBaseProductNumberDS1302BatteryBackupSwitchingBackupSwitchingCategoryIntegratedCircuits(ICs)Clock/Timing-RealTimeClocksCurrent-Timekeeping(Max)0.3A~1A@2V~5VDateFormatYY-MM-DD-ddFeaturesLeapYear,NVSRAM,Trickle-ChargerFunctionCalendar,Clock,NVTimekeepingRAM,TrickleChargerInterface3-WireSerialManufacturerMaximIntegratedMaximumOperatingTemperature+70CMinimumOperatingTemperature0CMountingStyleThroughHoleOperatingTemperature0C~70CPackageTubePackage/Case8-DIP(0.300,7.62mm)PackagingTubePartStatusObsoleteProductCategoryRealTimeClockRoHSNRTCBusInterfaceSerialRTCMemorySize31BSubcategoryClockTimerICsSupplierDevicePackage8-PDIPSupplyVoltage-Max5.5VSupplyVoltage-Min2VTimeFormatHH:MM:SS(12/24hr)TypeClock/CalendarVoltage-Supply,Battery2V~5.5VDS1302FeaturesCompletelyManagesAllTimekeepingFunctionsoReal-TimeClockCountsSeconds,Minutes,Hours,DateoftheMonth,Month,DayoftheWeek,andYearwithLeap-YearCompensationValidUpto2100o31x8Battery-BackedGeneral-PurposeRAMSimpleSerialPortInterfacestoMostMicrocontrollersoSimple3-WireInterfaceoTTL-Compatible(VCC=5V)oSingle-ByteorMultiple-Byte(BurstMode)DataTransferforReadorWriteofClockorRAMDataLowPowerOperationExtendsBatteryBackupRunTimeo2.0Vto5.5VFullOperationoUsesLessThan300nAat2.0V8-PinDIPand8-PinSOMinimizesRequiredSpaceOptionalIndustrialTemperatureRange:-40Cto+85CSupportsOperationinaWideRangeofApplicationsUnderwritersLaboratories(UL)RecognizedDS1302AdvantageTheDS1302trickle-chargetimekeepingchipcontainsareal-timeclock/calendarand31bytesofstaticRAM.Itcommunicateswithamicroprocessorviaasimpleserialinterface.Thereal-timeclock/calendarprovidesseconds,minutes,hours,day,date,month,andyearinformation.Theendofthemonthdateisautomaticallyadjustedformonthswithfewerthan31days,includingcorrectionsforleapyear.Theclockoperatesineitherthe24-houror12-hourformatwithanAM/PMindicator.InterfacingtheDS1302withamicroprocessorissimplifiedbyusingsynchronousserialcommunication.Onlythreewiresarerequiredtocommunicatewiththeclock/RAM:CE,I/O(dataline),andSCLK(serialclock).Datacanbetransferredtoandfromtheclock/RAM1byteatatimeorinaburstofupto31bytes.TheDS1302isdesignedtooperateonverylowpowerandretaindataandclockinformationonlessthan1W.TheDS1302isthesuccessortotheDS1202.InadditiontothebasictimekeepingfunctionsoftheDS1202,theDS1302hastheadditionalfeaturesofdualpowerpinsforprimaryandbackuppowersupplies,programmabletricklechargerforVCC1,andsevenadditionalbytesofscratchpadmemory.DS1302ApplicationsTheapplicationsofDS1302includeincorporateddigitalclocks/timersofvariousmodulesinourreallives.OtherequivalentsICsofRTCare:DS1307,DS3231,DS3232DS1302TypicalOperatingCircuitDS1302EnvironmentalandExportClassificationsAttributeDescriptionRoHSStatusRoHSnon-compliantMoistureSensitivityLevel(MSL)1(Unlimited)HowtoUseDS1302AtypicaloperatingcircuitforDS1302isgivenbelow.DS1302havetwopowerinput,oneisfromcellandotherisfromcontroller.Acrystaloscillatorof32.768kHzisusedtogeneraterequiredfrequency.ForinterfacingDataline,ResetPinandSerial-clockpinsofDS1302areconnectedwiththemicro-controller.DS1302BlockDiagramDS1302RTCModuleDS1302isatickle-chargetimekeepingchipwhichcontainsareal-timeclock/calendarand31bytesofstaticRAM.DS1302usesserialcommunicationtointeractwithmicrocontrollers.Also,itautomaticallyadjustthedateforthemonthwithfewerdays.Clockoperatesin24hror12hrformatwithanAM/PMindicator.DS1302chipisalsocommonlyusedasDS1302RTCmodulewhichcomeswitha32kHzcrystalandon-boardbatterybackupallinasmallSIPmodulethatiscompatiblewithabreadboard.DS1302moduleareusedbymakerswithArduino,RaspberryPiandotherMicro-controllers.ADS1302RTCmodulepinoutisshowninbelowimage.DS1302CommandByteAcommandbyteinitiateseachdatatransfer.TheMSB(bit7)mustbealogic1.Ifitis0,writestotheDS1302willbedisabled.Bit6specifiesclock/calendardataiflogic0orRAMdataiflogic1.Bits1to5specifythedesignatedregisterstobeinputoroutput,andtheLSB(bit0)specifiesawriteoperation(input)iflogic0orreadoperation(output)iflogic1.ThecommandbyteisalwaysinputstartingwiththeLSB(bit0).DS1302RegisterDS1302has12registers,ofwhich7registersarerelatedtocalendarandclock.ThestoreddatabitsareintheformofBCDcodes.Thecalendar,timeregistersandtheircontrolwordsareshowninTable1.Inaddition,DS1302alsohasyearregister,controlregister,chargingregister,clockburstregister,andRAM-relatedregisters.Theclockburstregistercanreadandwritethecontentsofallregistersexceptthechargingregisterinsequenceatonetime.TheDS1302andRAM-relatedregistersaredividedintotwocategories:OneisasingleRAMunit,with31intotal.Eachunitisconfiguredasan8-bitbyte,anditscommandcontrolwordisC0H~FDH.Amongthem,oddnumbersarereadoperations,andevennumbersarewriteoperations;theothertypeisRAMregistersinburstmode.Inthismode,all31bytesofRAMcanbereadandwrittenatonce,andthecommandcontrolwordsareFEH(write)andFFH(read).FAQWhatisDS1302?DS1302isatickle-chargetimekeepingchipwhichcontainsareal-timeclock/calendarand31bytesofstaticRAM.DS1302usesserialcommunicationtointeractwithmicrocontrollers.Also,itautomaticallyadjustthedateforthemonthwithfewerdays.WhatdoesanRTCdo?Areal-timeclock(RTC)isacomputerclock(mostoftenintheformofanintegratedcircuit)thatkeepstrackofthecurrenttime.Althoughthetermoftenreferstothedevicesinpersonalcomputers,serversandembeddedsystems,RTCsarepresentinalmostanyelectronicdevicewhichneedstokeepaccuratetime.HowdoyouuseRTC?WiringItUp.5VisusedtopowertotheRTCchipwhenyouwanttoqueryitforthetime.Ifthereisno5Vsignal,thechipgoestosleepusingthecoincellforbackup.ConnectGNDtocommonpower/dataground.ConnecttheSCLpintotheI2CclockSCLpinonyourArduino....ConnecttheSDApintotheI2CdataSDApinonyourArduino.DescriptionTheTDA2822isadual-channel,single-chippoweramplifierintegratedcircuitdevelopedbyStMICROelectronics.Itiscommonlyusedasanaudioamplifierinportablecassetteplayers,cassetterecorders,andmultimediaactivespeakers.Ithasthecharacteristicsofsimplecircuit,goodsoundquality,widevoltagerangeandsoon.Itcanworkinthecircuitformofstereosoundandbridgeamplification(BTL).HowtoMakeaStereoAmplifierUsingICTDA2822?CatalogDescriptionTDA2822PinoutTDA2822CADModelTDA2822ParameterTDA2822ApplicationsTDA2822FeaturesTDA2822AdvantagesWheretouseTDA2822AmplifierICHowtouseTDA2822AmplifierTDA2822SchematicDiagramTDA2822DocumentsandMediaTDA2822EnvironmentalandExportClassificationsTDA2822CircuitOrdering&QuantityTDA2822PinoutPinNumberPinNameDescription1,3OutputProvidestheamplifiedAudiooutput5,8InvertingInput(IN-)TheInvertingPinofanamplifierisnormallygrounded6,7Non-InvertingInput(IN+)TheNon-Invertingpinisprovidedwiththeaudiosignal4Vcc-Connectedtothenegativesupplyrail2Vcc+ConnectedtoPositiveSupplyRailTDA2822CADModelTDA2822SymbolTDA2822FootprintTDA2822ParameterAudio-LoadImpedance8OhmsBaseProductNumberTDA2822BrandSTMicroelectronicsCategoryIntegratedCircuits(ICs)Linear-Amplifiers-AudioClassClass-ABDescription/FunctionHeadphone/SpeakerFactoryPackQuantity25Features-Gain39dBHeight4.59mmIb-InputBiasCurrent0.1uAInputTypeSingleLength20mmManufacturer:STMicroelectronicsMaxOutputPowerxChannels@Load3.2Wx1@8Ohm;1.7Wx2@4OhmMaximumOperatingTemperature:+150CMfrSTMicroelectronicsMinimumOperatingTemperature-40CMountingStyleThroughHoleNumberofChannels2ChannelOperatingSupplyCurrent12mAOperatingSupplyVoltage5V,9V,12VOperatingTemperature-40C~150C(TJ)OutputCurrent1500mAOutputPower3.2WOutputSignalTypeDifferential,SingleOutputType1-Channel(Mono)or2-Channel(Stereo)PackageTubePackage/Case16-DIP(0.300,7.62mm)Package/CasePDIP-16PackagingTubePartStatusObsoletePd-PowerDissipation4000mWProductAudioAmplifiersPSRR-PowerSupplyRejectionRatio40dBSeriesTDA2822SubcategoryAudioICsSupplierDevicePackage16-PowerDIPSupplyTypeSingleSupplyVoltageMax15VSupplyVoltageMin3VTHDplusNoise0.2%TypeClassABType1-ChannelMonoor2-ChannelStereoUnitWeight0.057419ozVoltageSupply3V~15VWidth7.1mmTDA2822ApplicationsAMandFMRadioamplifiersPortablemusicplayersLowPowerAudioamplifiersWienbridgeoscillatorPowerAmplifiersAudioboostersTDA2822FeaturesDualAmplifiersinoneDIP-8similarforLM368.Givepowerwattsat1W+1Wat4ohmsspeakers.Itisenough.WearehappyListeninginourcorner.Startvoltagesupplyof1.8Vto15V.Thewidealot.Saveenergywithonly6mA,Min.Thebandwidthexpansionratesat40dB120kHz.CheapandeasytouseTDA2822AdvantagesTDA2822isalowpowerstereoOpAmplifierusedinWalkmanplayersandHearingaids.Itcangive250mWoutput.TDA2822isanidealOpampforlowoutputapplications.Itisagoodchoiceasapreamplifierinstereohighpoweramplifiercircuits.Ithastwoinputsandtwooutputswhichcandeliver250milliwattsoutputpower.TheamplifiercircuitwithintheICiswellsetfornoisefreeoperation.Outputscanbedirectlycoupledtothespeakersthroughthedecouplingcapacitors.WheretouseTDA2822AmplifierICTheTDA2822isaDualAudioAmplifierIC,meaningithastwoOp-Ampsinsideitspackage,andtheyarecommonlyusedforaudioamplificationbecauseoftheirwidebandwidthgain.Thetwooutputscandeliver250milliwattsoutputpower.ThisICcanbeusedinportableaudiosystems,preamplifiers,hearingaidminiradio,headphoneamplifier,etc.SoifyouarelookingforadualpackageOperationalamplifierICwithhigh-gain,andwidebandwidthforaudioamplification,thenthisICmightbetherightchoiceforyou.HowtouseTDA2822AmplifierAnapplicationcircuitfromTDA2822datasheetisgivenbelowTheleftloadisconnectedtooutputpin1oftheICthroughelectrolyticcapacitorC4,andtherightloadisconnectedtooutputpin3throughelectrolyticcapacitorC5.TheInvertingInputPins(5and8)areconnectedtothegroundviaelectrolyticcapacitors.Non-InvertingInputPins(7and6)areconnectedtoinput1andinput2.Pin2isconnectedtoDCsupplyandpin4isconnectedtoground.ElectrolyticcapacitorC3connectedacrossVCCandground,workasafiltercapacitor.TDA2822SchematicDiagramTDA2822DocumentsandMediaDatasheetsTDA2822DesignResourcesDevelopmentToolSelectorHTMLDatasheetTDA2822TDA2822EnvironmentalandExportClassificationsAttributeDescriptionRoHSStatusROHS3CompliantMoistureSensitivityLevel(MSL)1(Unlimited)TDA2822CircuitTDA2822TestCircuit(Stereo)TDA2822TestCircuit(Bridge)TDA2822TypicalApplicationinPortablePlayersTDA2822LowCostApplicationinPortablePlayersTDA28223VStereoCassettePlayerwithMototSpeedControlI.Description74LS138isa3-lineto8-linedecoder/demultiplexer.Thechipisdesignedtobeusedinhigh-performancememory-decodingordata-routingapplications,requiringveryshortpropagationdelaytimes.Inhighperformancememorysystemsthesedecoderscanbeusedtominimizetheeffectsofsystemdecoding.Thethreeenablepinsofchip(inwhichTwoactive-lowandoneactive-high)reducetheneedforexternalgatesorinverterswhenexpanding.CatalogI.DescriptionII.DigitalVoltmeterCircuitFAQOrdering&QuantityII.DigitalVoltmeterCircuitWeuseAD574andAT89C2051toformahighprecisiondigitalvoltmeter.TheschematicdiagramisshowninFigure1.AD574isa12-bitsuccessivecomparisonA/Dconverterwith12datalinesintotal.P1ofAT89C2051isdirectlyconnectedtothehigh8-bitdatalineofAD574.Thelow4-bitdatalineofAD574isdirectlyconnectedwiththeupperhalf4-bitp1.4-p1.7ofsingle-chipmicrocomputer.Datareadingisbasedonthecontrollineofsinglechipmicrocomputer.P3.5isconnectedtoAD574byteshortperiodcontrolline(A0).P3.4isconnectedtoreadconversiondatacontrolpin.AndP3.7isdirectlyconnectedwiththeterminalofindicatingworkingstatus(STS).Suchstructuredeterminesthatitcanonlybe8-bitoutput,sothedatamodeselectionendcanbedirectlygrounded.AT89C2051hasonly15I/Oportwires,11ofwhichareusedabove,andonly4ofthemareleft.Theoutputdataisoutputthroughtheserialportofthesingle-chipmicrocomputer,andanexternal74LS164(serialinandparallelout)decoderisconnectedforexpansion.Atthesametime,thedatadisplayedis4bits,andtheremaining2portlinesstillcannotmeettherequirements.A74LS138decoderisneededtogatetheaddressofthedisplayLED.Hereweusetheinputmodeof10Vrange.Pin13ofAD574istheinputterminalofthemeasuredvoltage.BecauseonlyoneAD574conversionchipisused,theCSterminalcanbedirectlygrounded.Theconverteruses12Vpowersupplyvoltageandtheworkingvoltageis+5V.74LS164isaserialinputandparalleloutputdecoder.TheBCDserialcodeoutputbyAT89C2051throughtheserialportisdecodedby74LS164andoutputasaseven-segmentBCDcode,whichisdirectlyconnectedtoa-goftheLED,andthedatalinesofthefourLEDsareconnectedonebyone.LEDdigitaltubeusescommonanodetype.Theaddresscodeoutputby74LS138isconnectedtothecommonterminalofLEDviaatransistor2SA1015(PNP).Thedisplayofthefour-digitLEDistime-sharingstrobethroughtheaddressline,whichisourcommonlyuseddynamicscanningdisplaymethod.Itisworthmentioningthatinthedynamicscanningdisplaymode,thefrequencyofdynamicscanninghascertainrequirements.Ifthefrequencyistoolow,theLEDwillflicker.Ifthefrequencyistoohigh,thelightingtimeofeachLEDistooshort,andthebrightnessoftheLEDistoolow.Itcantbeseenclearlywithnakedeye.Soitisgenerallyappropriatetotakeabout10ms.Thisrequiresthatwhenwritingaprogram,acertainLEDshouldbeonandkeptforacertainperiodoftime.Theprogramoftenusesthecalldelaysubroutine.FAQWhatisthedifferencebetween74hc138and74LS138?Bothhavethesamefunction.74HC138ismadeofhigh-speedCMOSprocess,withlowpowerconsumption,highoutput,lowlevelandwiderange.74LS138adoptstheearlybipolarprocess,anditsdrivingcapabilityisrelativelylarger.Whatisthefunctionaldifferencebetween74ls138decoderand74ls148?74ls138isa3-8wiredecoder/multiplexer,74ls148isan8-3wireoctalpriorityencoder.Oneisdecodingandtheotherisencoding.OppositeeffectWhatsthedifferencebetween74LS138Dand74LS138N?Thosetwoarethesamechip,DisSOPpackage,NisDIPpackage.Whataretheoutputcharacteristicsof74LS138decoder?UnderthepremisethattheenableterminalsS1(activehigh),S2(activelow),andS3(activelow)arevalidatthesametime,onlyoneoutputterminalislowatatime(therestarehigh);Iftheenableterminalisinvalid,theoutputisallhighlevel.Whatdothelettersandnumbersin74ls138standfor?74ls138isa3-8-linedecoder.Thenumber74representsthe74seriesofthe54/74series,andthe74serieshasanoperatingtemperatureof0degreesto70degrees.LSisaseries,representingthelow-powerSchottkyseries.138isthevarietycode.Whatstheworkingprincipleof74ls138?74LS138workingprinciple①Whenonestrobeterminal(E1)ishighlevel,andtheothertwostrobeterminals(E2)and(E3)arelowlevel,attheoutputterminalscorrespondingtoY0toY7,thebinarycodeofaddressterminals(A0,A1,A2)canbedecodedatlowlevel.Forexample:whenA2A1A0=110,theY6outputterminaloutputsalow-levelsignal.②UsingE1,E2andE3,itcanbecascadedtoexpandintoa24-linedecoder;ifanexternalinverterisconnected,itcanalsobecascadedtoexpandintoa32-linedecoder.③Ifoneofthestrobeterminalsisusedasadatainputterminal,74LS138canalsobeusedasadatadistributor.④Itcanbeusedin8086decodingcircuittoexpandmemory.

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Introduction74LS138isa3-lineto8-linedecoder/demultiplexer.Thechipisdesignedtobeusedinhigh-performancememory-decodingordata-routingapplications,requiringveryshortpropagationdelaytimes.Inhighperformancememorysystemsthesedecoderscanbeusedtominimizetheeffectsofsystemdecoding.Thethreeenablepinsofchip(inwhichTwoactive-lowandoneactive-high)reducetheneedforexternalgatesorinverterswhenexpanding.CatalogIntroductionIFullAdderCircuitIIResponderCircuitIIILogicFunctionIVFullSubtractorCircuitVThree-inputMajorityVotingFAQOrdering&QuantityIFullAdderCircuitThefulladderhas3inputterminals:An,Bn,Cn-1;2outputterminals:Sn,Cn.The74LS1383-lineto8-linedecoderhas3datainputterminals:A,B,C;3enableterminalsand8outputterminals.Here,the3datainputterminalsofthe3-lineto8-linedecodercanberegardedasthe3inputterminalsofthefulladder.Thatis,theinputsA,B,andCofthe3-lineto8-linedecodercorrespondtotheinputsAn,Bn,andCn-1ofthefulladderrespectively.Setthe3enableterminalsofthe3-lineto8-linedecodertotheeffectiveleveltomaintainnormaloperation.Thekeypointhereistodealwiththerelationshipbetweenthe8outputterminalsofthe3-lineto8-linedecoderandthe2outputsofthefulladder.UsetheoutputOUT(1,2,4,7)ofthe3-lineto8-linedecoderasa4-inputorgateinput,andthegateoutputasthesumoftheadder.UsetheoutputOUT(3,5,6,7)ofthe3-lineto8-linedecoderasa4-inputorgateinput,thegateoutputisusedasthecarryoutputoftheadder.Whentheinputoftheadderis:a=1,b=0,ci=1,theinputofthecorresponding3-lineto8-linedecoderisA=1,B=0,C=1.Theoutputofthedecoderisout(5)=1andtherestis0.Accordingtotheconnectionrelationshipdesignedabove,S=0,CO=1,whichsatisfiesthefunctionoffulladder.Figure1.FullAdderCircuitIIResponderCircuitFigure2.ResponderCircuitIIILogicFunctionF=ABC+ABC+ABC=111+110+101=Y7+Y6+Y5Accordingtotheruleof74LS138,Aisthelowbit(LSB)andDisthehighbit(MSB).The74LS138decodingoutputislowleveleffective.With74LS10NANDgate,theactuallogicisinputlowleveleffectiveorgate.Figure3.CircuitofLogicFunctionIVFullSubtractorCircuitFigure4.FullSubtractorCircuitVThree-inputMajorityVotingThedeviceconsistsofa3-lineto8-linedecoder(74LS138)andtwo4-inputNANDgates(74LS20).Therearethreebuttonsforuser.Pressthebuttontoagree,nottopressmeanstoreject.Whennoonepressesthebutton,orwhenonlyonepersonpressesthebutton,forexample,S1ispressed,butS2andS0arenotpressed.Theredlightison,thegreenlightisoff,andthebuzzerissilent,indicatingveto.Whentwoormorepeoplepressthebutton,forexample,ifS1andS2arepressed,theredlightwillbeoff,thegreenlightwillbeon,andthebuzzerwillsoundtoindicateapass.Use74LS138decoderandfour-inputNANDgate74LS20torealizethislogicfunction.Figure5.CircuitofThree-inputMajorityVotingFAQWhatisthedifferencebetween74hc138and74LS138?Bothhavethesamefunction.74HC138ismadeofhigh-speedCMOSprocess,withlowpowerconsumption,highoutput,lowlevelandwiderange.74LS138adoptstheearlybipolarprocess,anditsdrivingcapabilityisrelativelylarger.Whatisthefunctionaldifferencebetween74ls138decoderand74ls148?74ls138isa3-8wiredecoder/multiplexer,74ls148isan8-3wireoctalpriorityencoder.Oneisdecodingandtheotherisencoding.OppositeeffectWhatsthedifferencebetween74LS138Dand74LS138N?Thosetwoarethesamechip,DisSOPpackage,NisDIPpackage.Whataretheoutputcharacteristicsof74LS138decoder?UnderthepremisethattheenableterminalsS1(activehigh),S2(activelow),andS3(activelow)arevalidatthesametime,onlyoneoutputterminalislowatatime(therestarehigh);Iftheenableterminalisinvalid,theoutputisallhighlevel.Whatdothelettersandnumbersin74ls138standfor?74ls138isa3-8-linedecoder.Thenumber74representsthe74seriesofthe54/74series,andthe74serieshasanoperatingtemperatureof0degreesto70degrees.LSisaseries,representingthelow-powerSchottkyseries.138isthevarietycode.Whatstheworkingprincipleof74ls138?74LS138workingprinciple①Whenonestrobeterminal(E1)ishighlevel,andtheothertwostrobeterminals(E2)and(E3)arelowlevel,attheoutputterminalscorrespondingtoY0toY7,thebinarycodeofaddressterminals(A0,A1,A2)canbedecodedatlowlevel.Forexample:whenA2A1A0=110,theY6outputterminaloutputsalow-levelsignal.②UsingE1,E2andE3,itcanbecascadedtoexpandintoa24-linedecoder;ifanexternalinverterisconnected,itcanalsobecascadedtoexpandintoa32-linedecoder.③Ifoneofthestrobeterminalsisusedasadatainputterminal,74LS138canalsobeusedasadatadistributor.④Itcanbeusedin8086decodingcircuittoexpandmemory.Description74LS138isa3-lineto8-linedecoder/demultiplexer.Thechipisdesignedtobeusedinhigh-performancememory-decodingordata-routingapplications,requiringveryshortpropagationdelaytimes.Inhighperformancememorysystemsthesedecoderscanbeusedtominimizetheeffectsofsystemdecoding.Thethreeenablepinsofchip(inwhichTwoactive-lowandoneactive-high)reducetheneedforexternalgatesorinverterswhenexpanding.A24-linedecodercanbeimplementedwithnoexternalinverters,anda32-linedecoderrequiresonlyoneinverter.74LS138isusedinde-multiplexingapplicationsbyusingenablepinasdatainputpin.Alsothechipinputsareclampedwithhigh-performanceSchottkydiodestosuppressline-ringingandsimplifysystemdesign.CatalogDescriptionCatalogCADModelsFeaturesApplicationPinoutLogicDiagramPackageParametersProductComplianceComponentDatasheetProductManufacturerFAQOrdering&QuantityCADModels74LS138Symbol74LS138FootprintFeaturesDesignedSpecificallyforHigh-Speed:MemoryDecodersDataTransmissionSystems3EnableInputstoSimplifyCascadingand/orDataReceptionSchottky-ClampedforHighPerformanceApplicationLinedecodersServersDigitalsystemsLineDe-multiplexingTelecomcircuitsMemorycircuitsPinoutPinFunctionPinNameDescription1A0Addressinputpin2A1Addressinputpin3A2Addressinputpin4E1Enableinput(activeLOW)5E2Enableinput(activeLOW)6E3Enableinput(activeHIGH)7O7Outputpin78GNDGround9O6Outputpin610O5Outputpin511O4Outputpin412O3Outputpin313O2Outputpin214O1Outputpin115O0Outputpin016VCCPowersupplypinLogicDiagramPackageParametersFunctionDecoder,DemultiplexerTechnologyFamilyLSVCC(Min)(V)4.75VCC(Max)(V)5.25Channels(#)1Voltage(Nom)(V)5F@nomvoltage(Max)(MHz)35ICC@nomvoltage(Max)(mA)10tpd@nomVoltage(Max)(ns)41Configuration3:8ProducttypeStandardIOL(Max)(mA)8IOH(Max)(mA)-0.4RatingCatalogOperatingtemperaturerange(C)0to70Bits(#)8Digitalinputleakage(Max)(uA)5ESDCDM(kV)0.75ESDHBM(kV)2ProductComplianceECCNEAR99USHTS8542390001ComponentDatasheetDatasheet74LS138DatasheetProductManufacturerTexasInstrumentsInc.(TI)isanAmericantechnologycompanythatdesignsandmanufacturessemiconductorsandvariousintegratedcircuits,whichitsellstoelectronicsdesignersandmanufacturersglobally.ItsheadquartersareinDallas,Texas,UnitedStates.TIisoneofthetoptensemiconductorcompaniesworldwide,basedonsalesvolume.TexasInstrumentssfocusisondevelopinganalogchipsandembeddedprocessors,whichaccountsformorethan80%oftheirrevenue.TIalsoproducesTIdigitallightprocessing(DLP)technologyandeducationtechnologyproductsincludingcalculators,microcontrollersandmulti-coreprocessors.Todate,TIhasmorethan43,000patentsworldwide.FAQWhatisthedifferencebetween74hc138and74LS138?Bothhavethesamefunction.74HC138ismadeofhigh-speedCMOSprocess,withlowpowerconsumption,highoutput,lowlevelandwiderange.74LS138adoptstheearlybipolarprocess,anditsdrivingcapabilityisrelativelylarger.Whatisthefunctionaldifferencebetween74ls138decoderand74ls148?74ls138isa3-8wiredecoder/multiplexer,74ls148isan8-3wireoctalpriorityencoder.Oneisdecodingandtheotherisencoding.OppositeeffectWhatsthedifferencebetween74LS138Dand74LS138N?Thosetwoarethesamechip,DisSOPpackage,NisDIPpackage.Whataretheoutputcharacteristicsof74LS138decoder?UnderthepremisethattheenableterminalsS1(activehigh),S2(activelow),andS3(activelow)arevalidatthesametime,onlyoneoutputterminalislowatatime(therestarehigh);Iftheenableterminalisinvalid,theoutputisallhighlevel.Whatdothelettersandnumbersin74ls138standfor?74ls138isa3-8-linedecoder.Thenumber74representsthe74seriesofthe54/74series,andthe74serieshasanoperatingtemperatureof0degreesto70degrees.LSisaseries,representingthelow-powerSchottkyseries.138isthevarietycode.Whatstheworkingprincipleof74ls138?74LS138workingprinciple①Whenonestrobeterminal(E1)ishighlevel,andtheothertwostrobeterminals(E2)and(E3)arelowlevel,attheoutputterminalscorrespondingtoY0toY7,thebinarycodeofaddressterminals(A0,A1,A2)canbedecodedatlowlevel.Forexample:whenA2A1A0=110,theY6outputterminaloutputsalow-levelsignal.②UsingE1,E2andE3,itcanbecascadedtoexpandintoa24-linedecoder;ifanexternalinverterisconnected,itcanalsobecascadedtoexpandintoa32-linedecoder.③Ifoneofthestrobeterminalsisusedasadatainputterminal,74LS138canalsobeusedasadatadistributor.④Itcanbeusedin8086decodingcircuittoexpandmemory.

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I.IntroductionTheheartrateisakeyindicatorvaluereflectingthehealthofthebody.Simplyput,theheartratereferstothefrequencyofcardiovascularbeatswithin1minute.Thetestofheartratecanshowscientificevidenceinworksuchasdiseasediagnosis,patientcare,andathletetraining.Inrecentyears,manymedicalequipmentandfitnessequipmentdevelopedandmanufacturedbycountriesaroundtheworldhaveadoptedheartratetestpowercircuits.Thelowcostofproductdevelopmentandhighperformanceheartratetestpowercircuitshaveimportantapplicationvalues.ThearticleintroducesthiskindofheartbeatratedetectionsystembasedonAD620integratedICindetail.Usingtheexcellentlow-noisecharacteristicsofAD620integratedIC,pluseffectivefilteringandamplifyingcircuits,combinedwithmicroprocessorsolutions,ahigh-precisionheartratemonitoringsystemisobtained.Figure1AD620CatalogI.IntroductionII.AD620ChipIII.CircuitDesign3.1BlockDiagram3.2SignalExtractionCircuitBasedonAD6203.3FilterAmplifierCircuit3.4MicroprocessorCircuit3.5ExperimentalResultsandDiscussionIV.ConclusionFAQOrdering&QuantityII.AD620chipAD620isalow-cost,high-precisioninstrumentationamplifier.Itonlyneedsanexternalresistortosetthegain,andthegainrangeis1to10000.Inaddition,AD620adopts8-pinSOICandDIPpackage,thesizeissmallerthanthediscretecircuitdesign,andthepowerconsumptionislower,soitisverysuitableforbattery-poweredandportableapplications.Itscharacteristicsareasfollows:EASYTOUSEGainSetwithOneExternalResistor(GainRange1to10,000)WidePowerSupplyRange(2.3Vto18V)HigherPerformancethanThreeOpAmpIADesignsAvailablein8-LeadDIPandSOICPackagingLowPower,1.3mAmaxSupplyLOWNOISE9nV/Hz,@1kHz,InputVoltageNoise0.28Vp-pNoise(0.1Hzto10Hz)EXCELLENTDCPERFORMANCE(BGRADE)50Vmax,InputOffsetVoltage0.6V/Cmax,InputOffsetDrift1.0nAmax,InputBiasCurrent100dBminCommon-ModeRejectionRatio(G=10)EXCELLENTACSPECIFICATIONS120kHzBandwidth(G=100)15sSettlingTimeto0.01%III.CircuitDesign3.1BlockDiagramThesurfaceofthehumanskincontainshumanECG,EMG,andpowerfrequencysignals.Generally,thenoiseoftheECGsignalcontainingheartrateinformationismuchsmallerthanthatofthepowerfrequencysignal.InordertoextracttheweakECGsignal,alow-noiseoperationalamplifiermustbeusedandareasonablefilteramplifiercircuitmustbedesigned.Figure2isablockdiagramoftheheartratedetectionsystem.Thewholeheartratedetectionsystemconsistsoffourparts:thesensorheadincontactwiththehumanskinsurface,thesignalextractioncircuit,thefilteramplifiercircuitandthemicroprocessorcircuit.Thesensorheadisgenerallyametalthatiseasytoconductelectricity.Aftercontactingthesurfaceofthehumanskin,ithascomplexelectricalsignalssuchashumanECGsignals,electromyographicsignals,andpowerfrequencysignals.Weusethelow-noiseAD620operationalamplifierasthecorechipoftheheartbeatrateextractioncircuit.Inthefilteringandamplifyingcircuitpart,asimplelow-passfilteringcircuitisused.Theexperimentalresultsshowthatthisfilteringcircuitissufficienttoextracttheheartratesignal.Afterfilteringtheamplifiedsignal,anadjustablecomparatorcombinedwithatransistorcircuitisusedtoforma5voltTTLlevelsignal,andfinallyconnectedtothemicroprocessor,theheartbeatsignalisprocessedbythemicrocomputer,andtheheartbeatrateiscalculatedanddisplayed.Figure2Blockdiagramofheartratedetectionprinciple3.2SignalExtractionCircuitBasedonAD620AD620operationalamplifier,usuallyusedinhigh-precisiontestinstruments,themaximumnonlinearerrorof40ppm,themaximumvoltageoffsetof50uV,themaximumtemperaturedriftof0.6uV/℃,becauseofitslownoise,lowbiascurrent,lowpowerconsumptioncharacteristics,itItiswidelyusedinmedicalfieldssuchaselectrocardiogram(ECG)andbloodpressuremonitoring.Figure3isasignalextractioncircuitbasedonAD620,inwhichtheLEFT_ARM,RIGHT_ARM,LEGthreeleadsareconnectedtothealuminumsheet(iethesensorhead),whicharerespectivelyconnectedtotheleftandrighthandsandrightfeetofthehumanbody.OurexperimentalresearchresultsshowthattheR4gainofLEFT_ARMis1K,thecorrespondingAD620operationalamplifiergainis50.Toomuchgainwillweakenthefinalsignal-to-noiseratio,sotheR4resistancevalueshouldbesetreasonablyintheexperiment.The0.1uFcapacitancebetweentheLEFT_ARMandRIGHT_ARMleadsistoeffectivelyweakenthepowerfrequencynoise.TheLEGleadisconnectedtoAD620throughTL082A,whichprovidesthereferencepotentialofthehumanbodyforthedifferentialsignalofLEFT_ARMandRIGHT_ARM.Figure3SignalextractioncircuitbasedonAD6203.3FilterAmplifierCircuitFigure4isafilteramplifiercircuit.Threeoperationalamplifiersconstituteathree-stageamplification,eachamplifying100times.Duetocircuitloss,especiallythelossoftheisolationcapacitor,theactualsignalamplificationislessthan1milliontimes.TheratiooftheresistancevaluesofR6andR5,R9andR8,R11andR10inthecircuitdeterminesthemagnificationfactor,andtheseresistancevaluesshouldbeadjustedreasonablyinpracticalapplications.Alow-passfiltercircuitshouldbeusedwhileamplifyingthesignaltoachievetheeffectoffilteringpowerfrequencynoise.Sincethefrequencyofthepowerfrequencynoiseis50Hz,thedesignedfiltercircuithasapassbandbandwidthoflessthan50Hz,thatis,theRCtimeconstantofthecapacitorresistormustbeofthesameorderofmagnitudeasthepowerfrequencysignalperiod.R7andC10inthecircuitformalow-passfilter.Weuse1uFcapacitorisolationbetweenlevelsofamplification.Thesecapacitorswillattenuatethesignalatthesametime,andthethreeoperationalamplifiersareselectedforsignalamplification,sothesignal-to-noiseratioisimproved.Itshouldbepointedoutthatiftheisolationcapacitoristoolarge,itiseasytocausetheoutputelectricalsignaltodrift.Figure4FilteramplifiercircuitFigure5istheshapingcircuit.Theheartbeatratesignalandsignal-to-noiseratioofthe2ND_OUTleadarelargeenough(thepulserateoftheheartbeatrateis1~5V),afterthehalf-waveshapingofD1,thentheadjustablecomparator,andfinallythetransistorQ1isconvertedtothemicrocontrollerlevel.Figure5Shapingcircuit3.4MicroprocessorCircuitThefinalsignalisprocessedbyAT89C51,andtheheartrateisdisplayedbyLEDdigitaltube.ThemicroprocessorcircuitwithAT89C51asthecoreisverymature,soitsnoneedtorepeathere.3.5ExperimentalResultsandDiscussionFigure6showstheactualmeasurementresultsofthehumanheartrateusingtheabovesystem.Figure6(a)isthevoltagesignalafterthesignal2ND_OUTisshapedbyD1.ItcanbeseenfromthefigurethatthisisactuallyacompleteECGsignal.Inacycleofsignals,therearetwomoreobviouspulsesignals.Thispulsecharacteristicvariesfrompersontoperson.ItisfoundthatthereisatleastonepulsesignalthroughactualmeasurementoftheECGsignalsofdifferentpeople.Figure6(b)showstheelectricalsignalofHEART_PULSE,whichisobtainedafterthesignalofFigure6(a)passesthroughthecomparatorandthetransistorswitch.Thesignalcanbedirectlyinputtotheportofthemicroprocessor,andthemicroprocessorcalculatesandoutputstheheartrate.Figure6HeartratesignaldiagramWhendevelopingtheabove-mentionedheartratedetectionsystem,thereareseveralkeypointstopayspecialattentionto:(1)ConnectingcapacitorstoLEFT_ARMandRIGHT_ARMcangreatlyimprovethesignal-to-noiseratio;themainenergyoftheheartratesignalonLEFT_ARMandRIGHT_ARMisatafrequencyofabout1Hz,andthecapacitorisalow-passfilterthatcanfilterandsuppressnoise;Choosealargecapacitortoeliminatehigh-frequencynoise.Intheexperiment,a10uFnon-polarcapacitorisused,andtheeffectisverygood;(2)Thelow-passfiltercircuiteffectivelyweakensthepowerfrequencysignalandimprovesthesignal-to-noiseratio;itadoptsacombinationofactivefilteringandpassivefilteringtofilterwhileamplifying,whichhasabettereffectthanfilteringafteramplification;(3)Capacitorisolationattenuationandmulti-stageamplificationarebeneficialtoimprovethesignal-to-noiseratio;themainnoiseis50Hzpowerfrequencysignals.Althoughthemulti-stageamplificationandfilteringincreasethermalnoise,ithasgreatsuppressionofpowerfrequencynoise.Ofcourse,thenumberofamplificationstagescannotbeinfinite,andthebestnumberofstagesistheminimumsumofpowerfrequencynoiseandthermalnoise;(4)SmallcapacitorisolationshouldbeusedtosuppressDCsignaldrift.Thisisshownbytheexperimentalresults,andthereasonneedstobefurtherstudied.IV.ConclusionThisarticlediscussesaschemebasedonAD620chipheartratedetection,andintroducesthecircuitdesignofthesensorhead,signalextraction,filteramplificationandmicroprocessorthatmakeupthesystem.Givesthemethodtoimprovethesystemperformance.ExperimentsshowthatthesystemcanobtainbetterECGsignalsandaccurateheartrate.Theheartbeatratedetectionsysteminthisarticlehasstronganti-interferenceability,simplestructureandlowcost.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,sothattheamplifierissuitableformeasurementandelectronicinstruments

I.IntroductionTheamplificationofweaksignalshashighrequirementsandhighdifficulty.Thesignalamplificationisrelatedtotherequirementsofstabilityandaccuracyofsignalamplification.Differentialamplificationtechnologyhasthecharacteristicsofsuppressingcommonmodesignalsandonlyamplifyingdifferentialmodesignalswithhighgain,soitisappliedtosmallsignalamplificationtechnology.ThesystemdesignadoptstheAD620chipwithdifferentialamplificationfunctiontoamplifytheweakvoltagesignalofthestrainsensortoachievethehighprecisionrequirementsofthesystem.Thisarticleusesvirtualinstrumenttechnologytocollectandanalyzetheamplifiedsignal,andwritethecorrespondingdisplayinterface.Themeasurementdataisanalyzedbythesecond-orderinterpolationmethodtoverifytheaccuracyofthecircuit.AD620CatalogI.IntroductionII.SystemDesignIII.SystemHardwareCircuitDesign3.1PressureMeasurementCircuit3.2VoltageSignalAmplifierCircuit3.3ReferenceVoltageSourceCircuitandVoltageZeroingCircuit3.4Voltage-currentConversionCircuitIV.TheOverallSoftwareDesignoftheSystemV.QuantitativeTestingandResultAnalysis5.1DataProcessingMethod5.2DataProcessingResults5.3ErrorAnalysisVI.ConclusionFAQOrdering&QuantityII.SystemDesignThesystemisprovidedwithtwovoltagesof12Vand5VfromaDCstabilizedsource.Whensetting12Vpowersupply,thesystemvoltageoutputfullrangeis5V,andthesensorwithstandsstaticpressurefullrangeis19.6N.Whenmeasuringwithinthefull-scalerange,themaximumabsoluteerrorofthestaticpressuresignalis9.810-3N,andtherelativeerroris0.02%.Theoutputsignaloftheloadcellprovidestwooutputmodes:voltageoutputandcurrentoutputaftertheamplifiercircuit.III.SystemHardwareCircuitDesignTheoveralldesignprocessofthesystemisshowninFigure1.ThesystemhardwarecircuitismainlycomposedofLC7012loadcell,AD620instrumentationamplifier,referencevoltagesource,voltagezeroingcircuit,signalfilteringandshapingcircuitandvoltage-currentconversioncircuit.Figure1Systemhardwarecircuitoveralldesignprocess3.1PressureMeasurementCircuitPressuremeasurementadoptsLC7012loadcell,withfullbridgemeasurementcircuit.LC7012loadcellhasthefollowingtwocharacteristicswhensubjectedtopressure:(1)Underthesamepressure,thestrainofthesensorstraingaugeandtheoutputvoltageofthebridgeareconstantandhavenothingtodowiththeprecisepositionofthepressureactingontheloadendofthesensor.(2)Theoutputvoltageandpressureofthefullbridgecircuitcomposedofstraingaugesarebasicallylinear.The4piecesofresistancestraingaugesintheLC7012loadcellareattachedtothestrainzoneofthedouble-holebeam.Whenthereisstaticpressure,thedouble-holebeamproducesquadrilateraldeformationundertheactionofthepressureandthesupportingforceofthesystemchassisonthedouble-holebeam.Thefourstraingaugesareconnectedtoafullbridgecircuitinafullbridgemode.Undertheexcitationofthebridgevoltage,differentweakvoltagesignalsareoutputwithdifferentpressures,andtheamplifiercircuitamplifiestheweakvoltagesignalssentbythebridge.Thefull-bridgeequal-armbridgehassimplestructure,strongsymmetry,highsensitivity,andgoodconsistencyoftheparametersofeacharm.Theeffectsofvariousinterferencescancanceleachother,forexample,itcansuppresstheeffectsoftemperaturechangesandsuppresstheinterferenceoflateralforces.Itiseasiertosolvetheproblemofcompensationoftheloadcell.Thefull-bridgemeasurementcircuitenablestheoutputoftheweakvoltagesignaltoeliminateerrorscausedbythecircuititselfasmuchaspossible,andprovidestheinitialguaranteefortheoverallaccuracyofthesystem.3.2VoltageSignalAmplifierCircuitInordertoimprovetheamplificationaccuracyoftheweakvoltagesignaloutputbythebridge,thesignalamplifyingcircuitselectstheAD620chipproducedbyADIasthecoreelement,anddesignsaspecialadjustablereferencevoltagesourceforittomeetthereferencevoltagerequirementsofdifferentvoltagesources.Andtheneedtoaccuratelyamplifyweaksignals.Figure2AD620PinoutAD620isalow-cost,high-precisioninstrumentationamplifier.Itonlyneedsanexternalresistortosetthegain.Thegainrangeis1to10000dB.AndAD620powerconsumptionislow,themaximumoperatingcurrentis1.3mA.AD620hasthecharacteristicsofhighprecision(maximumlinearity4010-6),lowoffsetvoltage(maximum50V)andlowoffsetdrift(maximum0.6V/℃),makingitanidealchoiceforprecisiondataacquisitionsystemssuchassensorinterfaces.Figure2showsitspinarrangement.AD620monolithicstructureandlasercrystaladjustmentallowcircuitcomponentstobecloselymatchedandtracked,thusensuringtheinherenthighperformanceofthecircuit.AD620isathree-op-ampintegratedinstrumentationamplifierstructure,inordertoprotectthehighprecisionofgaincontrol,theinputtransistorprovidesdifferentialbipolarinput,andusesprocesstoobtainlowerinputbiascurrent,throughthefeedbackoftheinputstageinternalop-amp,Keepthecollectorcurrentoftheinputtransistorconstant,andaddtheinputvoltagetotheexternalgaincontrolresistorRG.AD620internalgainresistanceisadjustedtoanabsolutevalueof24.7k,soanexternalresistancecanbeusedtoachievepreciseprogrammingofthegain.ThegainformulaisThevoltagesignalamplifiedbytheAD620canpassthroughafilteringandshapingcircuitandbedisplayedindigitalformwithadigitaltubethroughtheanalog-to-digitalconvertermodule.Inordertofullyutilizeanddemonstratethefunctionsofvirtualinstruments,thesystemusesLabVIEWtodesignthecorrespondingsignalacquisitionandprocessingprogramanddisplayinterface.3.3ReferenceVoltageSourceCircuitandVoltageZeroingCircuitThereferencevoltagesourcecircuitismainlycomposedofaZenerdiodeLM285,alow-powerdualoperationalamplifierchipLM258,avariableresistorandanumberoffixedresistanceresistors,asshowninthelowerleftpartofFigure3.ThisreferencevoltagesourcecircuitcanprovideAD620with1.25Vor2.5Vaccuratereferencevoltage.Figure3VoltagesignalamplifiercircuitThevoltagestabilizingdiodeLM285providestheprimarystablevoltage,butthetemperaturedriftofthediodeislarge,andthevoltagestabilizationvalueofdifferentdiodesinthesamebatchisnotthesame,sothecorrespondingauxiliaryvoltagestabilizingcircuitmustbedesignedforit.TheoperationalamplifierLM258U1AamplifiesthevoltagefromtheZenerdiodeandfeedsbacktheoutputvoltagethroughthefeedbackresistorR2,makingtheoutputvoltagemorestable.ResistorR5andpotentiometerW1dividetheoutputvoltageoftheZenerdiode.PotentiometerW1hastwofunctions:(1)AdjustingW1canmakethevoltagefollowercomposedofoperationalamplifierLM258U1Bhavedifferentoutputvoltages,andthenprovidedifferentstablereferencevoltagestoAD620.(2)ThepotentiometerW1alsoplaysaroleofzeroadjustmentontheamplifyingcircuitcomposedofAD620.Thevoltagefollowerisusedbecausethevoltagefollowercanincreasetheinputimpedanceandreducetheoutputimpedance,andtherequirementofthepowersupplyisthatthecircuithasasmalleroutputresistance.AD620itselfhasaninternalzeroadjustmentfunction,butaccordingtoactualmeasurement,itisfoundthatwhenthedifferentialinputiszero,theoutputisnotzero,butaboutafewtenthsofmV.Therefore,inordertoimprovetheaccuracyoftheoutput,itisnecessarytoperformtheAD620Externalzeroadjustment,byprovidingdifferentreferencevoltagestotheAD620referencevoltagepins,theoutputvoltageoftheinstrumentationamplifierAD620canbezerowhenthedifferentialinputiszero.ThecircuitjustadjustsW1tomaketheoutputterminalofthevoltagefollowerhavedifferentvoltageoutput,adjuststhereferencevoltageofAD620,thusplaystheroleofzeroadjustmenttoAD620.TheinstabilityofthereferencevoltagewilldirectlyaffectthestabilityoftheamplifiercircuitcomposedofAD620,andleadtoinaccuracyofthefinaloutputresult.Therefore,thesystemdoesnotdirectlyusetherelativelystable-12Vor-5VprovidedbytheDCstabilizedsourceasthereferencevoltage.3.4Voltage-currentConversionCircuitThevoltage-currentconversioncircuitenablesthesystemtooutputintheformofcurrent.TheAD620iscombinedwithanAD705operationalamplifierandtworesistors(asshowninFigure4)toformaquietcurrentsource.AD705providesabufferforthereferencepin.Ensuregoodcommonmoderejection(CMR)performance.TheoutputvoltageofAD620appearsontheresistanceRL,thelatterconvertsitintoelectriccurrentoutput.Figure4Schematicdiagramofvoltage-currentconversioncircuitAD705isalow-power,bipolaroperationalamplifierwithabipolarfieldeffecttransistorinputstage.Therefore,ithasthecharacteristicsofhighinputimpedance,lowinputoffsetvoltage,smallinputbiascurrent,andsmallinputoffsetvoltagedrift.TheinputbiascurrenthasreachedthepAlevel.Itnotonlyhasmanyadvantagesofbipolarfieldeffecttransistorsandbipolaroperationalamplifiers,butalsoovercomesthedefectoflargebiascurrentdriftinthefulltemperaturerange.Inthefulltemperaturerange,thetypicalvalueofthebiascurrentofAD705onlyincreasesby5times,andthebiascurrentofthegeneralbipolarfieldeffecttransistoroperationalamplifierincreasesby1,000times.ComparedwithOP07,thetemperaturedriftvalueis1/2ofOP07,themaximuminputbiascurrentisonly1/5ofOP07,andtheinputoffsetvoltageisonly1/20ofOP07.Becauseitisabipolarfieldeffecttransistorinputpole,thesignalsourceimpedanceismuchhigherthanOP07,whileitsDCaccuracyremainsunchanged.IV.TheOverallSoftwareDesignoftheSystemThesystemsoftwareiswritteninLabVIEW.LabVIEWisagraphicalprogramminglanguage,whichiswidelyusedinvariousfieldsasastandardfordataacquisitionandinstrumentcontrolsoftware.LabVIEWisapowerfulandflexiblesoftware.Useittoeasilybuildyourownvirtualinstrument.Inthecaseofonepieceofhardware,differentfunctionsofdifferentinstrumentscanberealizedbychangingthesoftwareprogramming,whichisconvenientandfast.Combinedwiththenewdevelopmentdirectionofthecurrenttestingfieldinstruments,thefinaloutputanalogvoltagesignaliscollectedbyAdvantechsUSB4716universaldataacquisitionmoduleandtransmittedtothecomputer.UseNIvirtualinstrument(LabVIEW)todesignvoltagesignalacquisitioncontrolprogramandvoltagedatareal-timedisplayinterface.UseLabVIEWsoftwareplatformtoanalyzeandprocessthedigitalvoltagesignalfromUSB4716.ThepartprogramofLabVIEWvoltagesignalacquisitioncontrolanddisplayisshowninFigure5.Figure5VoltagesignalacquisitionprogramV.QuantitativeTestingandResultAnalysis5.1DataProcessingMethodSecond-orderinterpolation(parabolicinterpolation):select(x0,y0),(x1,y1),(x2,y2)correspondinginterpolationequationsfromasetofdata.5.2DataProcessingResultsInordertoobtainanaccuratecorrespondencebetweenpressureandvoltageandfacilitatesubsequentanalysisofabsoluteandrelativeerrors,theexperimentusesstaticmeasurementmethodstomeasureaseriesofstaticpressurevalues,andquantitativelyanalyzetheexperimentalresultstodeterminetheaccuracyofthecircuit.Commonlyusedwaveformtimedomainandfrequencydomainanalysismethods.Table1Brightness/ContrastComparisonPressure/N0...2.94...8.829.8...13.72...19.6219.6Voltage/V0...0.75...2.2472.498...3.498...4.755.001Measure20staticpressurevaluesfromsmalltolargewithinthefullscalerange,andmakethepressureincrement△thesame.Let△=0.98N,andusethesecond-orderinterpolationmethodtoanalyzetherelationshipbetweenvoltageandpressure.SelectthreerepresentativepointsfromTable1:(x0,y0)=(0,0);(x1,y1)=(2.498V,9.8N);(x2,y2):(5.001V,19.6N).Bringinsecond-orderinterpolationTherelationshipcurvebetweenthepressureonthesensorandthesystemoutputvoltageisY=(-1.56810-3)x2+3.927x(3)5.3ErrorAnalysisTheabsoluteerrorreflectsthedeviationofthemeasuredvaluefromthetruevalue,thatis,theabsolutevalueofthedifferencebetweenthemeasuredvalueandthetruevalue.Theabsoluteerrorcanbedefinedas:=|X-L|(4)Intheformula,istheabsoluteerror;Xisthemeasuredvalue;Listhetruevalue.Relativeerroristheratioofabsoluteerrortothemeasuredvalueortheaveragevalueofmultiplemeasurements,andtheresultisusuallyexpressedasapercentage,soitisalsocalledpercentageerror.Absoluteerrorcanindicatethereliabilityofameasurementresult,whilerelativeerrorcancomparethereliabilityofdifferentmeasurementresults.Whenmeasuringwiththesametool,thelargerthemeasuredvalue,thesmallertherelativeerrorofthemeasurementresult.TheabsoluteerrorandrelativeerrorofthestraingaugepressuresensortestsystemareshowninFigure6andFigure7.Thetwofiguresrespectivelyshowtheabsoluteerrorandrelativeerrorcurvesoftwootherdataprocessingmethods:linearinterpolationandaverageselectionmethod.ItcanbeseenfromFigure6andFigure7thatthecalculationaccuracyofthesecond-orderinterpolationmethodishigherthantheothertwomethods,whichalsoprovesthatthechoiceofthedataprocessingmethodiscorrect.Figure6AbsoluteerrorcurveFigure7RelativeerrorcurveVI.ConclusionKnownfromtherelativeerrorandabsoluteerrorgraphthat,themeasurementresulterrorofthecircuitintherangeof0~4.9Nisrelativelylarge,butitstillmeetsthesystemdesignrequirements.Afteranalyzingthesensorandtheexperimentalmeasurementcircuit,itisbelievedthatthereasonforthelargererrorcomesfromtherigidityofthecantileverbeammaterialofthesensorandtheflexibleinfluenceoftheviscousmaterialthatfixesthestraingauge.Becausetheaccuracyoftheweakvoltagesignaloutputbythebridgeisaffected,theerrorisalsoamplifiedafterpassingthroughtheamplifyingcircuit,resultinginalargererrorintheexperimentalresultwhenthemeasuredvalueissmall.Insummary,thepressuresignalamplificationsystemsatisfiesthedesignrequirementsofabsolutefull-scaleerror9.810-3Nandrelativeerror.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,sothattheamplifierissuitableformeasurementandelectronicinstrumentsDescriptionIRFZ44NisaN-channelPowerMOSFETs,thisblogcoversIRFZ44NMOSFETpinout,datasheet,equivalent,featuresandotherinformationonhowtouseandwheretousethisdevice.CatalogDescriptionIRFZ44NCADModelIRFZ44NPinoutIRFZ44NCircuitIRFZ44NApplicationsIRFZ44NFeaturesIRFZ44NAdvantageIRFZ44NPackageIRFZ44NParametersIRFZ44NDocumentsIRFZ44NProductComplianceIRFZ44NAlternativesIRFZ44NEquivalentsWheretouseIRFZ44NIRLZ44NandIRFZ44NDifferenceHowtouseIRFZ44NHowtoSafelyLongRunIRFZ44NinCircuitsIRFZ44NManufacturerComponentDatasheetFAQOrdering&QuantityIRFZ44NCADModelIRFZ44NSymbolIRFZ44NFootprintIRFZ44NPinoutPinNumberPinNameDescription1SourceCurrentflowsoutthroughSource2GateControlsthebiasingoftheMOSFET3DrainCurrentflowsinthroughDrainIRFZ44NCircuitSwitchingTimeTestCircuitUnclampedInductiveTestCircuitGateChargeTestCircuitPeakDiodeRecoverydv/dtTestCircuitIRFZ44NApplicationsBatteryChargersBatteryManagementSystemsSolarBatteryChargersApplicationsFastSwitchingApplicationsUninterruptiblePowerSuppliesMotorDriverCircuitsSolarUninterruptiblePowerSuppliesIRFZ44NFeaturesAdvancedProcessTechnologyUltraLowOn-ResistanceDynamicdv/dtRating175COperatingTemperatureFastSwitchingFullyAvalancheRatedLead-FreeIRFZ44NAdvantageIRFZ44NisawidelyusedMOSFETtransistordesignedtouseinvarietyofgeneralpurposeapplications.Thetransistorpossesseshighspeedswitchingcapabilitywhichmakesitidealtouseinapplicationswherehighspeedswitchingisacrucialrequirement.Thetransistoriscapabletodriveloadofupto49Aandthemaxloadvoltagecanbe55V.Howeverthepeakpulsecurrentcanbeupto160A.Theminimumthresholdvoltagerequiredforthistransistortomakeitinfullyopenstateis2Vto4V.Thistransistorcanalsobeusedasanaudioamplifierorinaudioamplifierstages;itiscapabletodelivermaximumaudiooutputof94W.IRFZ44NPackageTo-220ABPackageOutlineIRFZ44NParametersBrandInfineon/IRChannelModeEnhancementConfigurationSingleFallTime45nsForwardTransconductance-Min19SHeight15.65mmId-ContinuousDrainCurrent49ALength10mmManufacturerInfineonMaximumOperatingTemperature+175CMinimumOperatingTemperature-55CMountingStyleThroughHoleNumberofChannels1ChannelPackage/CaseTO-220-3Pd-PowerDissipation94WProductCategoryMOSFETProductTypeMOSFETRdsOn-Drain-SourceResistance17.5mOhmsRiseTime60nsSubcategoryMOSFETsTechnologySiTransistorPolarityN-ChannelTransistorType1N-ChannelTypeHEXFETPowerMOSFETTypicalTurn-OffDelayTime44nsTypicalTurn-OnDelayTime12nsUnitWeight0.211644ozVds-Drain-SourceBreakdownVoltage55VVgs-Gate-SourceVoltage-20V,+20VWidth4.4mmIRFZ44NDocumentsEOLEndofLifeNotification(PDF)ModelsIRFZ44NSymbolFootprintbySnapEDAProductCatalogsGateDriverSelectionGuide2019(PDF)SelectionGuide(PDF)IRFZ44NProductComplianceUSHTS8541290095TARIC8541100000ECCNEAR99IRFZ44NAlternativesIRF2807,IRFB3207,IRFB4710IRFZ44NEquivalentsIRFZ46N,STP55N06,2SK2376,BUK456-60H,STP50N06,2SK2312,2SK2376,BUZ102S,IRF1010AIRLZ44NandIRFZ44NDifferenceTheIRLZ44NandIRFZ44NMOSFETsareoftenconfusedamongeachotherandusedincorrectly.TheIRLZ44NisaLogiclevelMosfetwithaverylowgatethresholdvoltageof5V,meaningtheMOSFETcanbefullyturnedonwithjust5Vonitsgatepinwhichavoidstheneedforadrivercircuit.IRLZ44NTheIRFZ44NontheotherhandrequiresagatedrivercircuitiftheMOSFEThastobeturnedoncompletelyusingamicrocontrollerlikeArduino.Howeveritdoesturnonpartiallywithdirect5VformaI/Opin,buttheoutputdraincurrentwillbelimited.IRFZ44NWheretouseIRFZ44NTheIRFZ44Nisknownforitshighdraincurrentandfastswitchingspeed.AddingtothatitalsohasalowRdsvaluewhichwillhelpinincreasingtheefficiencyofswitchingcircuits.TheMOSFETwillstartturningonwithasmallgatevoltageof4V,butthedraincurrentwillbemaximumonlywhenagatevoltageof10Visapplied.IfthemosfethastobedrivendirectlyfromamicrocontrollerlikeArduinothentrythelogiclevelversionIRLZ44Nmosfet.HowtouseIRFZ44NUnliketransistorsMOSFETsarevoltagecontrolleddevices.Meaning,theycanbeturnedonorturnedoffbysupplyingtherequiredGatethresholdvoltage(VGS).IRFZ44NisanN-channelMOSFET,sotheDrainandSourcepinswillbeleftopenwhenthereisnovoltageappliedtothegatepin.Whenagatevoltageisappliedthesepinsgetsclosed.IfitisrequiredtobeswitchedwithArduino,thenasimpledrivecircuitusingatransistorwillworktoprovidetherequiredgatevoltagetotriggertheMOSFETtoopenfully.Forotherswitchingandamplifyingapplications,adedicatedMOFETDriverICisrequired.HowtoSafelyLongRunIRFZ44NinCircuitsTogetlongtermperformancewithIRFZ44Nitissuggestedtonotusethistransistoronitsmaximumratings.Usinganycomponentsonitsmaximumratingcancausestressonthecomponentandmaydamageorweakitsinsidecircuitrywhichresultinweakerperformance.Wealwayssuggestuseanycomponentatleat20%belowfrommaximumcapacityorspecifications.ThesamerulewillbeappliedforIRFZ44N.Themaximumdraincurrentis49amperesthereforedonotdriveloadofmorethan39amperes.Themaximumloadvoltageis55Vandforsafetydonotdriveloadofmorethan44V.TheGatetosourcevoltageshouldbeunder20Vandalwaysstoreoroperatethetransistorintemperatureabove-55centigradeandbelow+175centigrade.IRFZ44NManufacturerInfineonTechnologiesAGisaworldleaderinsemiconductorsolutionsthatmakelifeeasier,saferandgreener.MicroelectronicsfromInfineonisthekeytoabetterfuture.Inthe2019fiscalyear(ending30September),thecompanyreportedsalesofaround8billionwithabout41,400employeesworldwide.InfineonislistedontheFrankfurtStockExchange(tickersymbol:IFX)andintheUSAontheover-the-countermarketOTCQXInternationalPremier(tickersymbol:IFNNY).ComponentDatasheetIRFZ44NDatasheetFAQWhatisirfz44n?TheIRFZ44NisaN-channelMOSFETwithahighdraincurrentof49AandlowRdsvalueof17.5m.Italsohasalowthresholdvoltageof4VatwhichtheMOSFETwillstartconducting.Henceitiscommonlyusedwithmicrocontrollerstodrivewith5V.WhatarepowerMOSFETsusedfor?PowerMOSFETsarewidelyusedintransportationtechnology,whichincludeawiderangeofvehicles.Intheautomotiveindustry,powerMOSFETsarewidelyusedinautomotiveelectronics.PowerMOSFETs(includingDMOS,LDMOSandVMOS)arecommonlyusedforawiderangeofotherapplications.HowdoIuseirfz44n?IRFZ44NisanN-channelMOSFET,sotheDrainandSourcepinswillbeleftopenwhenthereisnovoltageappliedtothegatepin.Whenagatevoltageisappliedthesepinsgetsclosed.HowdoIturnonamosfetchannel?N-ChannelForanN-ChannelMOSFET,thesourceisconnectedtoground.ToturntheMOSFETon,weneedtoraisethevoltageonthegate.Toturnitoffweneedtoconnectthegatetoground.P-ChannelThesourceisconnectedtothepowerrail(Vcc).Whattodowithirfz44n?

74HC164DescriptionThe74HC164isan8-bitserial-in/parallel-outshiftregister.Thedevicefeaturestwoserialdatainputs(DSAandDSB),eightparalleldataoutputs(Q0toQ7).DataisenteredseriallythroughDSAorDSBandeitherinputcanbeusedasanactiveHIGHenablefordataentrythroughtheotherinput.DataisshiftedontheLOW-to-HIGHtransitionsoftheclock(CP)input.ALOWonthemasterresetinput(MR)clearstheregisterandforcesalloutputsLOW,independentlyofotherinputs.Inputsincludeclampdiodes.ThisenablestheuseofcurrentlimitingresistorstointerfaceinputstovoltagesinexcessofVCC.74HC164Catalog74HC164Description74HC164PinConfigurationandFunctions74HC164Features74HC164FunctionalBlockDiagram74HC164ApplicationsDifferencesBetween74HC164and74HC59574HC164PackageOutlineComponentDatasheetFAQOrdering&Quantity74HC164PinConfigurationandFunctionsPinFunctions:74HC164FeaturesWidesupplyvoltagerangefrom2.0to6.0VCMOSlowpowerdissipationHighnoiseimmunityInputlevels:1.For74HC164:CMOSlevel2.For74HCT164:TTLlevelGatedserialdatainputsAsynchronousmasterresetComplieswithJEDECstandardsJESD8C(2.7Vto3.6V)JESD7A(2.0Vto6.0V)Latch-upperformanceexceeds100mAperJESD78ClassIILevelBESDprotection:1.HBMJESD22-A114Fexceeds2000V2.MMJESD22-A115-Aexceeds200VMultiplepackageoptionsSpecifiedfrom-40Cto+85Cand-40Cto+125C.74HC164FunctionalBlockDiagram74HC164ApplicationsProgramableLogicControllersAppliancesVideoDisplaySystemsOutputExpanderDifferencesBetween74HC164and74HC59574HC595Pinout74HC595PinFunctionsPinNo.SymbolNameandFunction1,2,3,4,5,6,7,15QAtoQHDataoutput8GNDGround(0V)9QHSerialdataoutput10SCLRShiftregisterclearinput11SCKShiftregisterclockinput12RCKStorageregisterclockinput13GOutputenableinput14SISerialdatainput16VCCPositivesupplyvoltage74HC595hasalatch,sotheoutputcanremainunchangedduringtheshift;74HC164hasnolatch,soitchangeseverytimeashiftclockisgenerated.Thisisthebiggestdifferencebetweenthetwo74HC595usesspecialQ7pintorealizemulti-chipcascade;74HC164directlyusesoutputpinQ7tocascade74HC595hasenableOE,whenOEisinvalid,theoutputpinishighimpedance;while74HC164hasnoenablepinTheresetof74HC595isfortheshiftregister.IfyouwanttoresettheLATCHregister,youmustloadtheshiftregistercontentintothelatchregisterontherisingedgeofST_CP;thatistosay:74HC595resetissynchronous,74HC164resetisasynchronous,Sotheresetof74HC164iseasier74HC164hasacorresponding74HC165parallel-to-serialchip.74HC164PackageOutlinePackageoutlineSOT108-1(SO14)PackageoutlineSOT337-1(SSOP14)PackageoutlineSOT402-1(TSSOP14)PackageoutlineSOT762-1(DHVQFN14)ComponentDatasheet74HC164DatasheetFAQHowdoesthe74HC164transmitdatainthemicrocontrollercircuit?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.AD603IntroductionTheAD603isalownoise,voltage-controlledamplifierforuseinRFandIFAGCsystems.Itprovidesaccurate,pin-selectablegainsof11dBto+31dBwithabandwidthof90MHzor+9dBto51+dBwithabandwidthof9MHz.Anyintermediategainrangemaybearrangedusingoneexternalresistor.Theinputreferrednoisespectraldensityisonly1.3nV/Hz,andpowerconsumptionis125mWattherecommended5Vsupplies.CatalogAD603IntroductionAD603FeaturesAD603PinConfigurationandFunctionsAD603FunctionalBlockDiagramAD603WorkingModesAD603FunctionalEquivalentsAD603PackageOutlineAD603TypicalApplicationAD603ApplicationsAD603ApplicationNoteComponentDatasheetFAQOrdering&QuantityAD603FeaturesLinear-in-dBgaincontrolPin-programmablegainranges:11dBto+31dBwith90MHzbandwidth9dBto51dBwith9MHzbandwidthAnyintermediaterange,forexample,1dBto+41dBwith30MHzbandwidthBandwidthindependentofthevariablegain1.3nV/Hzinputnoisespectraldensity60.5dBtypicalgainaccuracyAD603PinConfigurationandFunctionsAD603FunctionalBlockDiagramFigure1AD603functionalblockdiagramItisnotdifficulttofindthatitisdifferentfromAD600inthat:thefixedgainamplifieritusescanchangethegainvalue.ThegainGFisdeterminedbytheconnectionformofVOUTandFDBK.WhenVOUTandFDBKareshort-circuited,GF=31.07dB;whenitisopen,GF=51.07dB;connectresistorREXTbetweenVOUTandFDBKtosetGFAnyvaluebetween31.07dB~51.07dB.However,thegainaccuracyinthismodeisreduced.Whentheexternalresistanceisabout2K,theerroristhelargest.IfanappropriateresistorisconnectedbetweenVOUTandCOMM,thegaincanbeincreased,upto60dB.AD603WorkingModesAD603hasthreeworkingmodes:Mode1:Short-circuitVOUTandFDBK,thisconnectioncanobtainthemaximumbandwidth-90MHz,andthegainrangeis-11.07dB~+31.07dB.AsshowninFigure2.Figure2ShortconnectionbetweenVOUTandFDBKMode2:ConnectaresistorREXTbetweenVOUTandFDBK,anda5.6pFcapacitorbetweenFDBKandCOMMasfrequencycompensation.Accordingtotherelationalexpressionoftheamplifier,selectingtheappropriateREXTvaluecanobtaindifferentgainrangevalues.WhenREXT=2.15Kohms,thegainrangeis:-1dB~+41dB.AsshowninFigure3.Figure3VOUTandFDBKaccessresistanceREXTMode3:OpenacircuitbetweenVOUTandFDBK,andconnectan18pFcapacitorbetweenVOUTandCOMMtoextendthefrequencyresponserange.Thismodeisahighgainmodewithagainrangeof8.93dB~51.07dBandabandwidthof9MHz.AsshowninFigure4.Figure4HighgainmodeIntheabovethreemodes,therelationshipbetweengainGFandcontrolvoltageVGisshowninFigure5.Figure5TherelationshipbetweengainGFandcontrolvoltageVGWhenVGisintherangeof-500mV~+500mVat40dB/V(thatis25mV/dB,whichisdifferentfromAD600s32mV/dB)forlineargaincontrol,therelationshipbetweengainG(dB)andVG(V)is:G=40VG+Goi(I=1,2,3),whereVG=VPOS-VNEG.G0iisthedifferentgainconstantsinthreemodes.Mode1:GOi=10dB;Mode2:GOi=10dB~30dB(determinedbytheexternalresistorREXT);Mode3:GOi=30dB.WhenthecontrolvoltageVGisoutside-500mV~+500mV,thegainGandVGnolongersatisfythelinearrelationship.WhenVG=-526mV,thegainisG=GF-42.14,whenVG=+526,thegainisG=GF.AD603TypicalApplicationFigure6AD603typicalapplicationcircuitFigure6isatwo-stageAD603amplifiercircuitwithautomaticgaincontrol.Inthefigure,Q1andR8formadetectortodetectchangesintheamplitudeoftheoutputsignal.TheautomaticgaincontrolvoltageVAGCisformedbyCAV,thedifferencebetweenthecurrentQ2andthecollectorcurrentofQ1flowingintothecapacitorCAV,anditsmagnitudechangeswiththeamplitudeoftheoutputsignalofA2,whichmakesitaddedtoA1andA2amplifier1.TheautomaticgaincontrolvoltageVAGCofthepinchangeswiththeoutputsignalamplitudechange,soastoachievethepurposeofautomaticallyadjustingtheamplifiergain.AD603FunctionalEquivalentsAD603PackageOutlineAD603ApplicationsRF/IFAGCamplifiersVideogaincontrolsA/DrangeextensionsSignalmeasurementsAD603ApplicationNote(1)Thepowersupplyvoltageshouldgenerallybeselectedas5V,andthemaximumshouldnotexceed7.5V.(2)Inthecaseof5Vpowersupply,theeffectivevalueoftheratedvoltageappliedtotheinputterminalVINPshouldbe1V,thepeakvalueis1.4V,andthemaximumshouldnotexceed2V.Ifyouwanttoexpandthemeasurementrange,youshouldaddalevelofattenuationinfrontofAD603.Inthisway,thetypicalvalueofthepeakoutputvoltagecanreach3.0V.Therefore,itisusuallynecessarytoaddafirstlevelofamplificationafterAD603toconnecttotheA/Dconverter.(3)Thevoltageappliedtothevoltagecontrolterminalmustbeverystable,otherwisethegainwillbeunstable,whichwillincreasethenoiseoftheamplifiedsignal.(4)Thesignalmustbedirectlyconnectedtopin4oftheamplifier,otherwisetheaccuracyoftheamplifierwillbereducedduetothelargeimpedance.ComponentDatasheetAD603DatasheetFAQWhatisAD603?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.

ADC0804DescriptionTherearemultiplekindsofAnalogtoDigitalConverters(ADC)whichareusedtoconvertthesignalformicroprocessorsorcontrollers.EveryADChasitsownspecificationandadvantagesonthebaseoftherequirement.HerewearegoingtodiscussADC0804ICwhichisknownasthelowvoltage8-bitAnalogtoDigitalConverter.ADC0804isalowvoltageICusetoconvertthelowvoltageanalogsignaltoan8-bitdigitalsignal.Itworkswith0-5Volts,has1Analoginputand8outputpins.ADC0804comeswithaninternalclockbuttoincreaseorchangetheclockthecyclewecouldusetheexternalclock.Alwayskeepinmindthatconversionspeedcannotbefasterthan110useitherweareusinganinternalclockorexternalclock.CatalogADC0804DescriptionADC0804PinConfigurationandFunctionsADC0804FunctionalBlockDiagramADC0804FeaturesWheretoUseADC0804HowtoUseADC0804ADC0804TypicalApplicationADC0804ApplicationsADC0804PhysicalDimensionsComponentDatasheetFAQOrdering&QuantityADC0804PinConfigurationandFunctionsADC0804FunctionalBlockDiagramADC0804FeaturesEasytointerfacewithallMicroprocessorsorworksStand-alone.Single-channel8-bitADCmoduleOn-chipClockavailable,noneedforexternalOscillator(Clock)Digitaloutputvariousfrom0to255WhenVref=5V,forevery19.53mVofanalogvaluetherewillbetheriseofonebitonthedigitalside(Stepsize)Availablein20-pinPDIP,SOICpackagesWheretoUseADC0804TheADC0804isacommonlyusedADCmodule,forprojectswereanexternalADCisrequired.Itisa20-pinSinglechannel8-bitADCmodule.MeaningitcanmeasureoneADCvaluefrom0Vto5Vandtheprecisionwhenvoltagereference(Vrefpin9)is+5Vis19.53mV(Stepsize).Thatisforeveryincreaseof19.53mVoninputsidetherewillbeanincreaseof1bitattheoutputside.ThisICisveryIdealtousewithMicroprocessorslikeRaspberryPi,Beagleboneetc.OreventouseasastandaloneADCmodule.EveryADCmodulerequiresaclocktofunction;thisICcomeswithitsowninternalclocksoyoudonthavetoworryaboutit.Hence,ifyouarelookingforacompactADCmodulewithadecentresolutionof8-bitthenthisICisforyou.HowtoUseADC0804SincetheICcomeswithaninternalclockwedonotneedmanycomponentstomakeitwork.HowevertomaketheinternalclocktoworkwehavetouseanRCcircuit.TheICshouldbepoweredby+5Vandbothgroundpinsshouldbetiedtocircuitground.TodesigntheRCcircuitsimplyusearesistorofvalue10kandcapacitorof100pf(approx)andconnectthemtoCLKRandCLKINpinsasshowninthecircuitbelow.Thechipselect(CS)andRead(R)pinshouldalsobegrounded.TheVrefpinisleftfreebecausebydefaultwithoutanyconnectionitwillbeconnectedto+5V.ThedigitaloutputwillbeobtainedfromthepinsDB0toDB7andtheanalogvoltageshouldbeconnectedtoVin(+)pinasshowninthecircuit.Alsonotethatanotherendofthevoltagesource(sensor/module)shouldalsobegroundedtothecircuitfortheADCconversiontowork.Now,fortheADCConversiontostartwehaveomaketheWrite(WR)pintogohighmomentarythiscanbedoneconnectingthepintoI/OofMPUandtogglingithighbeforeeveryADCread.OnlyifthisisdonetheADCvalueontheoutputsidewillbeupdated.Intheabovecircuit,Ihaveusedapotentiometertofeedinavariablevoltageof0Vto5VtotheVinpinandthepresentVoltageisreadusingavoltmeter.Asyoucanseeintheimagethevoltagevalueis1.55Vandtheresultingbinaryvalueis01001111.LetusseehowthisbinaryvaluecanbeconvertedtoAnalogvalue,sincewewillneeditwhileprogramming/designing.BinaryValue=01001111ConvertingtoDecimal=(0*128)+(1*64)+(0*32)+(0*16)+(1*8)+(1*4)+(1*2)+(1*1)=79AnalogVoltage=DecimalValue*Stepsize=79*19.53mV=1.54VTheobtainedvalueis1.54Vandthemeasuredvoltageis1.55Vwhichareverymuchclose.SothisishowyouuseanADC0804IC.ADC0804TypicalApplicationADC0804ApplicationsTransducer-to-microprocessorinterfaceDigitalthermometerDigitally-controlledthermostatMicroprocessor-basedmonitoringandcontrolsystemsADC0804PhysicalDimensionsDual-In-LinePackage(J)OrderNumberADC0801LJ,ADC0802LJ,ADC0801LCJ,ADC0802LCJ,ADC0803LCJorADC0804LCJADC0802LJ/883or5962-9096601MRANSPackageNumberJ20ASOPackage(M)OrderNumberADC0802LCWM,ADC0803LCWMorADC0804LCWMNSPackageNumberM20BMoldedDual-In-LinePackage(N)OrderNumberADC0801LCN,ADC0802LCN,ADC0803LCN,ADC0804LCNorADC0805LCNNSPackageNumberN20AMoldedChipCarrierPackage(V)OrderNumberADC0802LCV,ADC0803LCVorADC0804LCVNSPackageNumberV20AComponentDatasheetADC0804DatasheetFAQWhatisadc0804?TheADC0804isacommonlyusedADCmodule,forprojectswereanexternalADCisrequired.Itisa20-pinSinglechannel8-bitADCmodule.MeaningitcanmeasureoneADCvaluefrom0Vto5Vandtheprecisionwhenvoltagereference(Vrefpin9)is+5Vis19.53mV(Stepsize).Whatisthedifferencebetweenadc0804andmax1112?ADC0804isusedforparallelADCandMAX1112isusedforserialADC.Whichpinoftheadc0804indicatestheendofconversion?PIN-5Interrupt(INTR)ThispinautomaticallygoeslowwhentheconversionisdonebyADC0804orwhenthedigitalequivalentofanaloginputisready.PIN-6Vin(+)connectinputanalogsensorpin/inputvoltagetothispin.WhatareADCandDAC?ADCstandsforAnalogtoDigitalConverter,whichconvertstheanalogsignalintothedigitalsignal.DACstandsforDigitaltoAnalogConverteranditconvertstheDigitalsignalintoananalogsignal.Whatistheresolutionof8bitADC?Forexample,anADCwitharesolutionof8bitscanencodeananaloginputtoonein256differentlevels(28=256).Thevaluescanrepresenttherangesfrom0to255(i.e.asunsignedintegers)orfrom128to127(i.e.assignedinteger),dependingontheapplication.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.