LM1949 Injector Drive Controller (Rev. C) - TI.com

1 FEB1995 REVISEDMARCH2013LM1949 InjectorDriveControllerCheckforSamples:L M19491 FEATURESDESCRIPTIONTheLM1949linearintegr atedcircuitservesasan2 LowVoltageSupply(3V )excellentcontroloffuelinjectordrivecirc uitryin AdaptabletoAllInjectorCurrentLevelscurre ntrequiredtoopena solenoidisseveraltimes HighlyAccurateOperationgreaterthanthecur rentnecessarytomerelyholdit TTL/CMOSC ompatibleInputLogicLevelsopen;therefore, theLM1949,bydirectlysensingtheactualsole noidcurrent,initiallysaturatesthedriver ShortCircuitProtectionuntilthe peak injectorcurrentisfourtimesthatof HighImpedanceInputtheidleor holding current(Figure19 Figure22). ExternallySetHoldingCurrent, thenautomaticallyreducedtothesufficienth olding InternallySetPeakCurrent(4 IH) , ExternallySetTime-Outthetotalpowerconsum edbythesystemis ,ahigherdegreeof AvailableinPlastic8-PinPDIP correlationoffueltotheinputvoltagepulse( ordutycycle)isachieved, 5V 10%supply,theICis FuelInjectiontypicallyoperableovertheent iretemperaturerange ThrottleBodyInjection( 55 C to+125 C ambient)withsuppliesaslowas3 coldcrank AirandFluidValvesconditionswhenthebatter yvoltagemaydroplowenoughtoderegulatethe5 -voltpowersupply.

2 DCMotorDrivesTheLM1949is availableintheplasticPDIP,(contactfactor yforotherpackageoptions). ,standardwarranty,andusein 1995 2013, FEB1995 (1)(2)SupplyVoltage8 VPowerDissipation(3)1235mWInputVoltageRa nge 40 C to+125 CStorageTemperatureRange 65 C to+150 CJunctionTemperature150 CLeadTemp.(Soldering10sec.)260 C(1)AbsoluteMaximumRatingsindicatelimits beyondwhichdamagetothedevicemayoccur.(2) If Military/Aerospacespecifieddevicesarereq uired,pleasecontacttheTexasInstrumentsSa lesOffice/Distributorsforavailabilityand specifications.(3)Foroperationin ambienttemperaturesabove25 C,thedevicemustbederatedbasedona 150 C maximumjunctiontemperatureandathermalres istanceof100 (VCC= ,VIN= ,TJ= 25 C,Figure1, unlessotherwisespecified.)SymbolParamete rConditionsMinTypMaxUnitsICCS upplyCurrentOffVIN= 0V1123mAPeakPin8 = 0V2854mAHoldPin8 Open1626mAVOHI nputOnLevelVCC= 253+25 AIOPO utputCurrentPeakPin8 = 0V 10 22mAHoldPin8 Open 5mAVSO utputSaturationVoltage10mA,VIN= ,tt RTCT90100110%2 SubmitDocumentationFeedbackCopyright 1995 2013, FEB1995 1995 2013,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback3 ProductFolderLinks:LM1949LM1949 SNLS349C FEB1995 (continued) 1995 2013, FEB1995 REVISEDMARCH2013 TypicalPerformanceCharacteristics(contin ued) 1995 2013,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback5 ProductFolderLinks.

3 LM1949LM1949 SNLS349C FEB1995 controlorientedprocessor(COPS ), microprocessor, ,in theformofa squarewavewitha variabledutycycleand/orvariablefrequency ,is typicalsystem,inputfrequencyis ,theengineexhaustismonitoredandtheair-to -fuelmixtureisvaried(viathedutycycle)tom aintaina perfect,orstochiometric, a ,it is necessarytobeabletodesigna modelfora , , ,if pronouncedenough,canbeavaluableaidin determiningthecurrentnecessarytoopena inductancemanifestsitselfasa breakpointin ,thecurrentnecessarytoovercometheconstri ctiveforcesofthatparticularinjectoris TypicalFuelInjector6 SubmitDocumentationFeedbackCopyright 1995 2013, FEB1995 REVISEDMARCH2013 PEAKANDHOLDCURRENTST hepeakandholdcurrentsaredeterminedbythev alueofthesenseresistorRS. ThedriverIC,wheninitiatedbya logic1 signalatPin1, ratedependentuponL1, R1, ,andwhenthisdropreachesthepeakthresholdl evel,typically385mV,theICis closedloopsystemtomaintaintheholdreferen cevoltage,typically94mV,acrossRS.

4 Oncetheinjectorcurrentdropsfromthepeakle veltotheholdlevel,it preferablewhenworkingwithsolenoids,since thecurrentrequiredtoovercomekineticandco nstrictionforcesisoftena ,powerdissipationin thesolenoidsandQ1is , it ,a peakcurrentofapproximately4 . , ,IRdropswithinthecomponentleadsorprinted circuitboardmaycreatesubstantialerrorsun lessappropriatecareis (Pins4 and5 respectively),shouldbeKelvinconnectedtoR S. (withoutplated-throughholes) ,whenthebatteryvoltageis lowduetoenginecranking,orjustundercharge d, ,theinjectorcurrentcanbeseentobeleveling outat3 amps,or1 ampsmayoverheattheinjectors,thetimerfunc tionontheICwillforcethetransitionintothe holdstateafteronetimeconstant(thetimecon stantis equaltoRTx CT), orwhenthevoltageontheTIMERpin(Pin8)isgre aterthantypicallyVSUPPLYx 63%. notneeded,it canbedisabledbygroundingtheTIMERPin(Pin8 ).Forsystemswheretheinitialpeakstateisno trequired,( ,wherethesolenoidcurrentrisesimmediately totheholdlevel), donebysettingthetimeconstantequaltozero, ( ,CT= 0).

5 LeavingRTin placeis Figure1. However,theactualusefulrangeofthetimerex tendsfrommicrosecondstoseconds, reset(discharged)whentheINpin(Pin1)is belowtheVOL(MIN) (VBE) bydischargingit witha ,a F capis resetin approximately25 (fromPin2 toPin3) , F workwellwiththecircuitofFigure1. F (disc)providesa closeoptimuminchoicebetweeneconomy,speed , , F ,however, 1995 2013,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback7 ProductFolderLinks:LM1949LM1949 SNLS349C FEB1995 inductive,a voltagespikeis producedatthecollectorofQ1anytimetheinje ctoris ,(whenthecurrentis reducedtoonefourthofitspeakvalue),andals oattheendofeachinputpulse,(whenthecurren tisreducedtozero).Thezenerprovidesa currentpathfortheinductivekickback, ,theratedzenervoltageatthesystempeakcurr entmustbelessthantheminimumbreakdownofQ1 . Also,evenwhileZ1isconductingthemajorityo ftheinjectorcurrentduringthepeak-to-hold transition(seeFigure20), ,asdescribedin thefollowingtext,canbecorrectedif theICdemands94mVacrossRS, ,thesafeoperatingarea(SOA)ofQ1mustinclud etheholdcurrentwitha notdesired,thezeneranodemaybereconnected tothetopofRSasshowninFigure21.

6 Sincethevoltageacrossthesenseresistornow accuratelyportraystheinjectorcurrentatal ltimes, usuallyonlymillisecondslong,Q1couldsuffe rpermanentdamageunlessbufferedbytheinjec torandZ1. Thereis onereasonwhya zeneris preferredovera clampdiodebacktothebatteryline, 1995 2013, FEB1995 Figure1 is dependentuponseveralexternalfactors, , ,ina typicalcycleofoperation, usuallymuchlongerthanthepeakstate,andint hepeakstatenearlyallpoweris storedasenergyinthemagneticfieldoftheinj ector, lessaccurateinthecaseoflowbatteryvoltage ,it Typicalvaluesaregivenin parentheses:RS= SenseResistor(0,1 )VH= SenseInputHoldVoltage(.094V)VP= SenseInputPeakVoltage(.385V)VZ= Z1 ZenerBreakdownVoltage(33V)VBATT= BatteryVoltage(14V)L1= InjectorInductance(.002H)R1= InjectorResistance(1 )n= DutyCycleofInputVoltageofPin1 (0to1)f= FrequencyofInput(10 Hzto200Hz)Copyright 1995 2013,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback9 ProductFolderLinks:LM1949LM1949 SNLS349C FEB1995 :(1)SWITCHINGINJECTORDRIVERCIRCUITT hepowerdissipationofthesystem,andespecia llyofQ1, canbereducedbyemployinga , , :Thelargeamplitudeswitchingvoltagesthata representontheinjectorcananddogeneratea tremendousamountofradiofrequencyinterfer ence(RFI).

7 Becauseofthis, , , theonlyadditionalcomponentsrequiredaretw oexternalresistors,RAandRB. Additionally,thezenerneedstobereconnecte d,asshown,toRS. Theamountofrippleontheholdcurrentis easilycontrolledbytheresistorratioofRAto RB. RBis keptsmallsothatsenseinputbiascurrent( )hasnegligibleeffectonVH. Dutycycleandfrequencyofoscillationduring theholdstatearedependentontheinjectorcha racteristics,RA, RB, andthezenervoltageasshownin thefollowingequations.(2)10 SubmitDocumentationFeedbackCopyright 1995 2013, FEB1995 REVISEDMARCH2013 Asshown, fourfoldreductioninpowerinQ1. However,thepowerdissipationofthezener(wh ichisindependentofthezenervoltagechosen) 1995 2013,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback11 ProductFolderLinks:LM1949LM1949 SNLS349C FEB1995 1995 2013, FEB1995 REVISEDMARCH2013 REVISIONHISTORYC hangesfromRevisionB (March2013)toRevisionCPage 1995 2013,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback13 ProductFolderLinks: LM1949 PACKAGE OPTION 1 PACKAGING INFORMATIONO rderable DeviceStatus(1)Package TypePackageDrawingPinsPackageQtyEco Plan(2)Lead/Ball Finish(6)MSL Peak Temp(3)Op Temp ( C)Device Marking(4/5)SamplesLM1949N/NOPBACTIVEPDI PP840 Green (RoHS& no Sb/Br)CU SNLevel-1-NA-UNLIM-55 to 125LM1949N (1) The marketing status values are defined as follows:ACTIVE: Product device recommended for new : TI has announced that the device will be discontinued, and a lifetime-buy period is in : Not recommended for new designs.

8 Device is in production to support existing customers, but TI does not recommend using this part in a new : Device has been announced but is not in production. Samples may or may not be : TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check for the latest availabilityinformation and additional product content : The Pb-Free/Green conversion plan has not been (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement thatlead not exceed by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used betweenthe die and leadframe.

9 The component is otherwise considered Pb-Free (RoHS compatible) as defined (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed by weightin homogeneous material) (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuationof the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line.

10 Lead/Ball Finish values may wrap to two lines if the finishvalue exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on informationprovided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken andcontinues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual OPTION 2 IMPORTANTNOTICET exasInstrumentsIncorporatedand its subsidiaries(TI) reservethe rightto makecorrections,enhancements,improvement sand otherchangesto its semiconductorproductsand servicesper JESD46,latestissue,and to discontinueany productor serviceper JESD48, latestrelevantinformationbeforeplacingor dersand shouldverifythat suchinformationis semiconductorproducts(alsoreferredto hereinas components )