设计参考、源码手册1746个zhcs

ZHCS297–OCTOBER查询样品 说专为与消费型UPS系统中的12V铅酸电池一起使 具有运行时间显示功能的bq78412铅酸电池充电状态 (SoC)指示器是一款完整的独立型电池电量监测解决 案，专为单12V铅酸电池而设计。bq78412利用一 10-LED（发光二极管）条形图来显示电池的剩余运（充电期间）显示的10-LED条形 时间（放电期间）和百分比(%)容量（充电期间）

应 12V

串行端口能够操作一个红外(IR)接口，以实现无连©2010,TexasInstrumentsPleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplications©2010,TexasInstrumentsPRODUCTIONDATAinformationiscurrentasofpublicationdate.ProductsconformtospecificationsperthetermsoftheInstrumentsstandardwarranty.Productionprocessingdoes EnglishDataSheet:necessarilyincludetestingofallThesedeviceshavelimitedbuilt-inESDprotection.TheleadsshouldbeshortedtogetherorthedevicecedinconductivefoamduringstorageorhandlingtopreventelectrostaticdamagetotheMOSgates. UMVoltageappliedtoVVoltageappliedtoVRS+,RS–Differential(VRS+–VCommonmode(VRS+,VVoltageappliedtoAVDDandVVoltageappliedtootherVDiodecurrentatanydevice2Stressesabovetheseratingsmaycausepermanentdamage.Exposuretoabsolute umconditionsforextendedperiodsmaydegradedevicereliability.Thesearestressratingsonly,andfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthosespecifiedisnotimplied.VDDreferstovoltageonDVDDandAVDDMENDEDOPERATINGSupply4VOperatingBatteryCurrentmeasurement,ACurrentmeasurement,AMEASUREMENTACCURACY(12-VBatteryvoltageShuntvoltageTemperatureTimingaccuracyofinternalSpecifiedat12SpecifiedatfullOffsetcalibrationofthetemperaturetakescepriortothisCalibratedclockfrequency,toleranceovertemperature0°CtoCapacitylearningisdonepriortoUARTCOMMUNICATIONSPORT Data9600CommandresponseTransmitintercharacter4umtimefromhosttransmissionoflastcommandbytetofirstresponsebytheumtimeintervalbetweenstartbitsfordataorresponsebeingtransmittedfromtheCURRENTOPERATINGTYPICALConnectedtoUPSandgasgaugingactive.DisyisactiveandnotNotconnectedtoUPS.DisyisactiveandnotNotconnected.DisyELECTRICALREG33load100µA≤ILOAD≤100mA,TJ=100µA≤ILOAD≤100mA,–40°C≤TJ≤ADCbasicSensevoltagemeasurementstep4ShuntcurrentmeasurementstepAFullscalecurrentsensevoltageSense1Package

(TopView)

ThermalpadisonthebottomsideoftheN/C=noPINIConfigurationinput.ConnecttoIConfigurationinput.ConnecttoP3.3-Vpowertooglogic.TypicallyconnectedtoPConnecttoOBuzzeroutput.ActivehighwhenalarmconditionisOActivehighoutput,turnsondisyenabletransistor.Notrequiredinallapplications.BlanksdisyduringP3.3-Vsupplytothedigitallogic.Connecta2.2-µFcapacitortoVSS.TypicallyconnectedtoPConnecttoPRegulated3.3-VpowerIConnecttoexternalRCnetworkforpower-up–,noconnectionICurrentsenseICurrentsense9IUARTRX6OI2CclockII2Cclockforinternaluse.ConnecttoSCLpin2OLow-to-hightransitionclocksdataintoexternalserialin,paralleloutshift7OIRXCVRShutdown;HIGH=XCVRinshutdown,LOW=XCVR5I2CI2Cdataforinternaluse.ConnecttoSDApin3OSerialdisydatatoserialin,paralleloutshiftregister.AlowbitturnsonanTestpin,noTestpin,noTestpin,noTestpin,noTestpin,no8OUARTTXPInputtointernalISensevoltage.ConnecttobatteryIInputterminalof8-MHzcrystaloscillatororcrystalpin.(Optional:CanbeleftunconnectedtouseinternalOOutputterminalof8-MHzcrystaloscillatororcrystalpin.(Optional:Canbeleftunconnectedtouseinternal1–No4TYPICAL+

2.2

100

1050

VBAT+SDASDA

SCLA1

1 A0RS+

CF

10

10

10383736

RS–VSAVSSAVDDDISPEN

10470(x

10

47

1VCC17

RTTEStatus/RTTEStatus/

35665849372

SDATSCLKN/CN/CN/CN/CN/CN/C

1289147

Q0Q1Q2Q3Q4Q5Q6Q7

1to15 6.3

RSVD 470.0016.3

44RST

RSVD12B72B7D48596XOUT42

Q0

Q6Q7u SoHSoH(1)CF=0.1µFto1

APPLICATIONThebq78412isacompletePb-Acidgas-gaugewitharun-timedisyandwarrantyinformationstorage.Itsupportslargebatteriesuptoaumcapacityof327Ahrwhenmeasuredatthe20hourrate.Measurementinputsincludethe12-Vnominalbatteryvoltageandthebatterycurrent.Coulombcountingondischargeandchargeallowsastate-of-chargecalculationandrun-time-to-emptyondischargeestimation.Cumulativeusageinformationisperiodicallyandpermanentlystoredinternallyandmayberetrievedonlybyaspecialsequencingoperationperformedbythemanufacturer.Operationofthebq78412requiresnouserin ction.Duringchargeanddischarge,theLEDdisyisautomaticallyactivatedwhenchargeordischargecurrentisdetectedaboveaconfigurablethreshold.CurrentSense,BatteryVoltage,Temperature,andTimeThebq78412measureschargeanddischargecurrentusingalow-value(between1and3mΩ)senseresistorcedinthenegativepowerpathofthecircuit.Thissenseresistormaybeassimpleasapieceofthermallystablemetalortheleadpowerpostonthebatteryitself.Calibrationofthissenseresistorisrequiredincircuit(inmodule).Theprintedcircuitboard(PCB)designermustconsidertheimpactofdriftand/orvariationinthesenseresistorvalueovertimeandtemperature,includingself-heatingtemperatureeffects.Thebq78412doesnotcompensateforsuchchanges.ThevoltagemeasuredbetweentheRS+andRS–pinsisscaledbythesenseresistorvalue(setinMeasScaleparameter)tocalculatethecurrentvalue.TheumdifferentialvoltageallowedbetweentheRS+pinandtheRS–pinis160mV.Alternatively,avoltageproportionaltothecurrent(derivedusingmeansotherthanasenseresistor,butwithinrangeoftheallowabledifferential)couldbeappliedtotheterminalstoprovidethecurrentmeasurement.Thebq78412measuresthebatteryvoltagebetweentheVSandAVSSThebq78412hasanon-chiptemperaturesensor.Thebatterytemperatureisassumedtobeequaltotheon-chipTimemeasurementisreferencedtoaninternaloscillator.However,formoreaccuracy,anexternal8-MHzcrystaloscillatororcrystalcanbeused.ThisisenabledbysettingDevConfig2[15]=1.Theswitch-overhappensonlyafterahardwareorsoftwarereset.State-of-Charge(SoC)Gas-Thebq78412providescapacityandrun-time-to-emptyestimatesforPb-Acidbatteriesusingarateandtemperaturecompensatedcoulombcountingalgorithm.Thegas-gauginginformationisusedtodrivethelocalLEDdisywithrun-time-to-emptyCapacitycorrectionissupportedbasedonthedischargecurrent.A64-bytebatterycharacterizationtablecontainsbatteryperformancedatathatisusedtoadjusttheremainingcapacityandrun-time-to-emptyasafunctionofdischargerateandtemperature.Thisinformationisuniquetoeachbatterymodelandisprogrammedatthebatterymanufacturingfacilitybasedonbatteryperformancedataprovidedbythemanufacturer.ChargeEfficiencyThebq78412providesaparameter,ChgEffthatallowsforcorrectionofaccumulatedchargeinthebatteryduetochargeefficiency.Duringcharge,thepassedchargeismultipliedbythechargeefficiencyandtheresultisaddedtotheremainingcapacity.Forexample,ifChgEffissetto85(representing85%),when100Ahhavebeenmeasured,only85Aharerecordedasactuallybeingaccumulated.WiththedefaultsettingfortheChgEff=100,allchargecurrentisaccumulated.GasGaugingAfteraDuringnormaloperation,thelastlearnedfullchargecapacity(FCC),elapsedtimeandotherimportantvariablesarestoredinpermanentmemory.If,forsomereasonthebatterydischargestothepointwherethereisnolongersufficientvoltageforthebq78412tooperate,itshutsdown.Undersuchconditions,whenthedevicepowersup,thesevariablesarerestoredandbatteryisassumedtobeat50%relativeSoC.Ifachargecurrentispresent,thedevicebeginstomeasuretheaccumulatedchargeandtime.Chargingproceedsasnormalwiththeappropriateend-of-chargedetectioncriteria.Ifthebq78412powersupandthereisnocurrent,thedevicegoesintoidlestatefollowedbysleepstateuntilacurrentisdetected.BatteryCapacityThebq78412hastwomechanismsforupdatingthebatterycapacityasthebatteryages.(Notethattheinitialcapacityprogrammedintothebq78412couldbeinerrorduetomanufacturingtolerancesorformationprocedures.Thistranslatestoagasgaugingerroruntilthebatterycapacityisaccuraylearned.)BoththeLearnedCapacitymethodandAge-BasedCapacitymethodoperateindependentlyandbothmaybeenabledordisabledseparayinordertomaintainthecorrectmeasureofcapacityofthebatteryoveravarietyofoperatingconditions,butitissuggestedthatbothbeenabledforoptimalperformance.LearnedCapacityWhenDevConfig1[14]issetto"1",thebq78412opportunisticallylearnsthefullchargecapacity(FCC)ofthebatterybasedonaqualifieddischarge.Acompletedischargefromfullychargedtofullydischargedwithnochargingeventsraisingtheremainingstateofcharge(SoC)above80%isconsideredqualified.Aninternalstatevariablequalifieddischarge(QD)isusedformaintainingthestatusofdischargequalification.QDisinitiallydisabled.Whenthebatteryhasreachedthefullychargedstate,QDissettoenabledanddischargelearnaccumulatorisclearedtozero.Whenadischargebegins,QDissettoactive.WhileQDisactive,allpassedcharge(positiveornegative)isaccumulatedinthedischargelearnaccumulator.Ifatanytime(whileQDisinanactivestate)achargingeventraisesSoCabove80%,QDissettodisabledandthedischargelearnaccumulatorisignored.IfthebatteryreachesthefullydischargedstateandQDisstillactive,thealgorithmlearnsFCCbasedonthedischargelearnaccumulatorandthecurrentloadde-ratingusing1.FCCDischargeLearnDeratingisthecapacityderatingfractionasafunctionofload Age-BasedCapacityThecounterfortheelapsedtimestartswhenthedeviceisWhenDevConfig1[15]issetto"1"(non-default),thebq78412updatestheFCCbasedonelapsedtimeandanagingalgorithmwithmanufacturerdefinedparameters.Thebq78412decrementstheFCCby0.100AheveryCapDeradaysuntilDerateChangedayshaveelapsed,afterwhichtheFCCdecrementsbythesameamounteveryCapDerateHdays.InthiswaytheFCCisregularlyde-rated(decremented)atregularintervalsindependentlyofthelearnedcapacityThevaluesforCapDera,DerateChange,andCapDerateHmustbecarefullychosentoimplementanappropriateage-basedcapacitydecreaseformula.Forexample:Assuminga100Ahbattery(whennew)anda3%/yearcapacityfadeforthefirst3yearsanda4%/yearfadeafterwards,theparametersmightbesetasfollows:3%of100Ah=3Ahdecreaseinone3Ahdecreasein0.1Ahsteps=30separatestepsover365365days/30decrementsteps=onedecrementstepevery12.1days SoCapDera 4%of100Ah=4Ahdecreaseinoneyear4Ahdecreasein0.1Ahsteps=40separatestepsover365365days/40decrementsteps=onedecrementstepevery9.1days SoCapDerateH=9Finally,3yearsis365daysx3=1095days SoDerateChange=1095Notethatduetoslightroundingerrors(12daysinsteadof12.1days,etc.)theactualcapacityrepresentedattheendofanytimeinternal(oneyear,twoyears,etc.)maybeoffbyasmallfraction.Intheexampleabove,theactualimplementationcalculatestobeaslistedbelow(assumingnochangestoFCCfromthelearnedcapacitymethodoccur):Initialcapacity=100Ahandfullchargecapacity(FCC)decremented0.1Ahevery12days:Endofyear1capacity(atday360)=100Ah–3.0Ah=97Ahand(3.0Ah/100Ah)=3%Endofyear2capacity(atday732)=97Ah–3.1Ah=93.9Ahand(3.1Ah/93.9Ah)=3.3%Endofyear3capacity(atday1095)=93.9Ah–3.0Ah=90.9Ahand(3.0Ah/90.9Ah)=Totalfromtime0toYear3:(100Ah–90.9Ah)/100Ah=9.1%/3years=图1showshowtheFCCdecreaseswithtimeandhowtheparameterscontrolthis.Notethattheparametervaluesusedin图1aredifferentfromthevaluesusedinthepreviousexample.

Value(100Derate

图1.AgeBasedCapacityStateofHealth(SoH)Thestateofhealthindicationcanbeconfiguredeitheronthenumberofcharge/dischargecyclesthathaveoccurredorareducedfullchargecapacity.Dischargeandchargebyanamountequaltothedesigncapacityofthebatteryconstitutesonecycle.Areducedfullchargecapacity(FCC)couldbeobtainedbyeitherofthetwocapacitylearningThenumberofcyclesortheFCCatwhichtheWARNandRECEindicationsareprovided,areconfigurable.TheparametersusedforstateofhealthincludeTheRECEorWARNLEDisturnedonwhentheoneortheotherofthetwostateofhealthconditionsoccur.SeetheStatusLEDssectionfordetailsonstatusindicatorLEDoperation.Gasgauginganddeviceoperationarenotaffectedwhenastate-of-healthindicationhasbeendetected.DisThebq78412supportsuptoa10-segmentLEDdisyinbargraphformat.Duringadischarge,itshowsruntimetoemptyatthecurrentdischargerateandduringcharge,thisshows%SoC.Thebq78412alsosupportsbatterystatus DisydataaretransmittedseriallytoexternalshiftregisterswhichareusedtolatchandturnontheexternalLEDs.Theshiftregistersareupdatedwhenastatuschangeisdetected.Disyuseisnotrequired.Instead,anexternaldevicemayquerythebq78412forstatusviatheuniversalasynchronousreceiver/transmitter(UART)port.Thebq78412canalsobeconfiguredtoautomaticallybroadcastthestatusthroughtheUARTTXDpin.SeetheStatusBroadcastsection.BarGraphDisThebq78412supportsuptoa10-segmentLEDdisyinbargraphformat.ThesizeofthebargraphdisyisdefinedinDevConfig1[5:2]withadefaultvalueof10.Duringdischarge,thebargraphshowsruntimetoemptyatthecurrentdischargerate.EachbarrepresentsaruntimetoemptyuptoaumnumberasdefinedbytheDsplyConf1throughDsplyConf5parameters.Eachbyteindicateshowmuchruntime(inminutes)isallocatedtotherespectiveLED.Thetotaltimerepresentedbythedisyisthesumofthetimeineachparameter.Forexample,wheneachparameterissetto30minutes,thetotaldisytimeis300minutesorfivehours.Whenthecalculateddischargeruntimetoemptyisgreaterthantheumtimeforthedisy,allLEDsareturnedon.Inthedefaultmode,eachLEDrepresents½houror30minutesremainingruntime.WhenoneLEDison,thereisatleast½hourofremainingrunDuringcharge,theLEDsrepresentthe%SoCbasedoncapacityinamp-hoursandthenumberofLEDsdefinedinDevConfig1[5:2].WhenthedisysizeinDevConfig1[5:2]issetto10,eachLEDrepresents10%ofcapacity.WhenthedisysizeinDevConfig1[5:2]issetto5,eachLEDrepresents20%ofcapacity.表1.DsplyConfParameterTimeinTimeinTimeinTimeinTimeinTimeinTimeinTimeinTimeinTimein表2.BarGraphDisyOperationDuringDischarge–FiveLEDExample,DefaultDsplyConf(1)Exampleassumesbatterystateofhealthis表3.BargraphDisyOperationDuringCharge–5LEDPERCENT100andFull(1)ExampleassumesbatterystateofhealthisStatusStatusindicatorsdescribedin4maybepopulatedasdesired.Theoutputsignalscouldalsobeusedtodrivemulti-colorLEDswherethestatusisindicatedbythecolor.表4.StatusIndicatorSTATUSREBatterystateofTurnedonwhenbatteryend-of-lifeconditionisdetectedeitherwhencyclecountreachesthevalueofLifeCyclesparameterorwhenfullchargecapacity(FCC)dropsbelowthevalueinEolCapparameterTurnedonwhencyclecountreachesthevalueofLifeCycleWarnparameterorwhenfullchargecapacity(FCC)hasdroppedbelowtheEolCapWarnlevel.OnwhennostateofhealthconditionModeofOnwhenbatteryisOnwhenbatteryisOnwhenqualifiedfullchargeconditionis图2showstheapplicationschematicshowingthe10-barLEDbargraphdisyandstatusLED

RTTERTTE

1289147

Q0Q1Q2Q3Q4Q5Q6Q7

1289

Q0SoHQ2SoHQ3147

Q4Q5Q6Q7

UDG图2.10-BarLEDBarGraphDisyandStatusLEDBuzzerAbuzzercanbesettobeeponvariousconditions.BitsintheDevConfig2registercontrolthenumberofbeepssoundedoneachcondition.Eachbeepissoundedfor1secondandgaps(thatis,silenceperiod)betweenbeeps(ifsetformultiplebeeps)arealsoof1secondduration.Settingthenumberofbeepsto0foraconditionisequivalenttodisablingthebuzzeroperationforthatcondition.Onehourafteranovervoltageorundervoltageconditionisdetected(andthebuzzersounds)thedevicechecksforthisconditionagain.Thebuzzeragainsounds(thesamenumberofbeeps)iftheconditionpersists.Fromthenon,thisconditionisnotcheckedforuntilthebatteryvoltagereturnstothenormal表5.DevConfig2ParameterRTTE=0minutes,during0toLED0turnsRTTE=timeinLED0,duringLED1turnsRTTE=timeinLED0+timeinLED1,duringLED2turnsRTTE=timeinLED0+timeinLED1+timeinLED2,duringBatteryvoltage>0toBatteryvoltage<OperationalThebq78412supportsthreeoperationalActiveWhenthebq78412detectsthatthebatteryisbeingchargedordischarged(Currentmagnitude≥TransToActive),itenterstheactivestate.Uponentrytotheactivestate,thedisyisactivatedandrun-time-to-emptyor%SoCisIdleWhenthebq78412detectsthattheobservedcurrentmagnitudeislessthanorequaltoIdleThresh,itenterstheIdlestate.InIdlestate,thedisyisactiveandremainsatthelastdisyedvaluewhenintheactivestate.SleepIfthebq78412isintheidlestateformorethanthenumberofsecondsspecifiedinSleepTime,itentersthesleepstate.Insleepstate,thedisyisturnedoff.Ineachofthestates,thebq78412periodicallymeasurescurrent,voltage,temperature,recordselapsedtime,andupdatesthewarrantyrecord.Also,theUARTinterfaceremainsactiveinallstates(includingbroadcasts,ifenabled).Coulombcountingisdisabledintheidleandsleepstates. y|Current|<|Current|> Time>

|Current|> y3.OperationalCOMMUNICATIONANDThebq78412providesaUARTcommunicationsinterfaceforparameterinitializationduringsystemconfigurationandtest.Thisinterfacealsoprovidesreal-timemeasurementcapabilityandaccesstostoredbatteryperformancedata.ThisinterfacecanbeusedwithRS-232,IrDA,RS-485,oranyothertransceiverthatiscompatiblewithNRZ-orIrDA-formatteddatastreams.Theserialinterfacealwaysoperatesinmulti-dropmode.Thedefaultaddressis0xFF.Theaddresscanbechangedinparameterflashparameter,MultiDropAdr.Thisdesignallowsmultiplebatteriestobesupportedinasystemandaccessedfromasinglepoint.Communicationstothebq78412isviamessages.Thefirstbytetransmittedtothebq78412istheaddressbyte.Subsequentbytesarethemessage.Byteswithinamessagemustbeseparatedbylessthan10bittimes.Messagesmustbeseparatedbymorethan10bittimes.Thebq78412isconfigurableforeitherNRZ- patiblebitDevConfig1[13:12]=[0,0]:Multi-dropmodewithNRZencoding.RS-232,RS-485,orwirelesstransceiverscanbeused.(default)DevConfig1[13:12]=[0,1]:Multi-dropmodewithIrDAencoding.IrDAtransceiverscanbeWhenreal-timedataarebeingaccessedand/orwhenthecommunicationsmodeisactiveforconfiguration,powerconsumptionmayincrease.Thecommunicationsinterfacehasthefollowingfixeddatarate9600or1200baudrate(setby8No1stopNoflow图4showsUARTEncodingwaveforms.图5showsthemulti-dropoperationdata

图4.UART>10 Blockof Blockof TXD,TXD,SP=StopbitST=StartblockistheItfollowsanidleperiodof10bitsormore

TXD,RXDTXD,RXDSP8-bit8-bit8-bit

图5.Multi-DropCommandSetandStatusThissectiondescribesthebq78412communications,commandset,andstatusCommandCommunicationsbetweenthebq78412andexternalhostdeviceconsistsofmessageThehosttobq78412commandsarealwaysseven(7)byteslongwiththegeneralformatshownGeneralCommandFormatHosttoTheaddressisahexadecimalnumberthatdistinguishesbetweentargetbq78412devices.Thedefaultaddressis0xFF.TheheaderIDisahexadecimalnumberthatdistinguishesbetweenindividualChecksumisXORofallbytes(excludingchecksum)includingheaderID=0xFFXORAddressXORIDXORParam0…..XORParam3Thebq78412sendsaresponsewithitsaddress,ACKrequesteddataifany,andchecksumuponsuccessfulreceptionofacommandthatisaddressedtoit.Thebq78412sendsaresponsewithitsaddress,NACK,andchecksumifacommandpacketaddressedtoithasbeencorrectlyreceivedbutthecommandisnotimplementedornotallowedtobeusedduetothesecurityThebq78412doesnotrespondtopacketsthathaveadifferentaddressorwhenthechecksumisThetransmissionofanyrequesteddatafollowsthetransmittedACKAddressesareinLittleEndianformat(leastsignificantbitReadorwritedataareinLittleEndianGeneralResponseCodefrombq78412toResponseByten-Byten-ACKResponsefrombq78412tohost,noresponseACK=ACKResponseCodefrombq78412tohostwithACK=Byten-Byten-NACKResponsefrombq78412toNACK=BroadcastMessagefromACK=ChecksumisXORofallbytes(excludingchecksum)includingaddressbyteandACK=0xFFXORAddressXORACK/NACKXORbyte0XORbyte1…..XORbyten-2XORbyten-1WhendataarenotrequestedonlytheAddress,ACK,andchecksumaretransmitted.Thebq78412usesthe"!"characterastheACKresponsecode.Itsvalueis0x21.Thebq78412uses0x15asNACKresponsecode.SingleWordHostrequesttoAddressAddressDataDataNote:ThememoryaddressisabyteaddressandmustbeanevenResponsefromtohosttoCommandNote:Dataaccessisafunctionofsealedlevel.IfaccesstoamemorylocationisprohibitedduetoseallevelthenthereisaNACKresponsefromthebq78412.Single/MultipleWordHostrequesttoAddressAddressDataLSBDataMSB…DataLSBn-DataMSBn-Note:TheDataLSBDataMSB…DataLSBn-DataMSBn-CommandNote:Dataaccessisafunctionofsealedlevel.IfaccesstoamemorylocationisprohibitedduetoseallevelthenthereisaNACKresponsefromthebq78412.ReadDeviceTypeandHostrequesttoResponsefrombq78412toNote:Firmwareversion,revision,andbuildarereportedSetHostrequesttoByte3Byte0Responsefrombq78412toCommandSetSealedLevel1fromHostrequesttoByte3Byte0Responsefrombq78412toCommandResetHostrequesttoResponsefrombq78412toNote:Thisresponseissentwhenthebq78412isreset.Whenthedevicereceivesavalidresetcommandthedeviceisreset,thensendstheresetACKmessage.CommandResetCumulativeHostrequesttoResponsefrombq78412toCommandSetSealedLevel1fromHostrequesttoResponsefrombq78412toCommandSetHostrequesttoResponsefrombq78412toCommandInitializeState-of-ChargeThiscommandinitializestheSoCreportedbythebq78412totheSoC%parameter,stheFCCtothevalueintheDesignCapacityparameter,clearsCycleCount,setsthelastdischargetoDesignCapacity/20,andinitializesallgasgaugingvariablestocorrespondtothewrittenSoClevel.HostrequesttoResponsefrombq78412toCommandStatusThebq78412canbeconfiguredtoautomaticallybroadcastastatusmessageblockwhenDevConfig1[0]=1.ThisoptionallowstheoutputoftheUARTtobeconnectedtoawirelesstransmittersobatterystatuscanberemoyreceivedanddisyed.Automatictransmissionofthebroadcaststatusmessageblockissuspendedfor60secondswhenacommandisreceived,aftertransmissionofthecurrentframeiscompleted.Automaticstatustransmissionrestartsaminimumof60secondsaftercompletionoftheresponsetothereceivedcommand.Theaddressisincludedinthestatusblocksinceitmaybedesiredtohaveonereceiverunitmonitorseveralbatteries.表6liststhebroadcaststatusmessageblockwordsintheorderthattheyaretransmitted.表6.bq78412BroadcastStatusMessageDevice01Addressof11Indicates22Batterystatus.SeedescriptioninBatteryStatusWord-42Battery62Battery82Batterycurrent.Positivevalue=chargecurrent,negativevalue=dischargecurrent.1002Remainingbatterycapacityderatedasfunctionofdischarge1002Learnedbatterycapacityatfullcharge,rated1002Runtimetoemptyderatedasafunctionofdischargecurrent.Onlyvalidduringdischarge.2Numberoffulldischargecyclesor2BatterycurrentaveragedbasedonCurrentAvgTime1002DeratedAvailable1002Accumulatedmissedchargeduetomultipledischargesoccurringbeforeafullchargehasoccurred.%2Batteryrelativestateof%1=0xFFXORbyte0XORbyte1…..XORbyte24XORByteoffsetsarecountedfromthestartofthebroadcastmessageDatawordsaretransmittedinLittleEndianformat(leastsignificantbyteWhilethebroadcastmessageisbeinggeneratedandtransmitted,receptionofcommandsissuspended,therefore,theresponsetothecommandsentmayarriveafterabroadcastmessage.Anyexternaldeviceshouldverifythattheresponseitreceivestoacommanddoesnotappeartobeabroadcast.Thebq78412maintainsa16-bitmasterbatterystatusword.Thiswordcanbeaccessedatanytimeandisalsotransmittedinthebroadcaststatusmessageblock.表7.bq78412BatteryStatusSTATUS01=11=21=31=battery41=batteryRe51=rece61=overcurrentoncharge,chargecurrent>71=overcurrentondischarge,dischargecurrent>81=overcharge,batteryvoltageabove91=overtemperature,batterytemperatureabove1=overdischarge,batteryvoltagebelow1=undertemperature,batterytemperaturebelow1=underchargedbatteryasdefinedbyconfigurationofMissChgLimparameter.Indicatesthatthebatterymustbecharged.1=end-of-dischargeconditiondetected.Clearedwhencharge[0,0]=Sealedlevel[0,1]=SealedLevel[1,0]=SealedLevelSeedescriptionin表4StatusIndicatorbq78412RegistersandThebq78412maintainsthestatusofnumerousbatteryperformancevariablesinitson-chipregisters.Thedeviceregistersarealsousedtoretrievethebatteryoperationallimits.Nopasswordisrequiredtoaccesstheseregisters.Theregistersareread-only.Batteryinformationisretrievedbyissuingmessagecommandsovertheserialinterfacetoaccessthespecificregisters.Registerscanbereadindividuallyorasasequentialblockofregisters.Allregistersare16-bitregistersormultiplesof16bits.8.bq78412Registers(StoredinVolatile2Batterystatus.Seedescription–SBatteryUBatterySBatterycurrent.Positivevalue=chargecurrent,Negativevalue=dischargecurrent.100URemainingbatterycapacityderatedasfunctionofdischarge100ULearnedbatterycapacityatfullcharge,rated100URuntimetoemptyderatedasafunctionofdischargecurrent.Onlyvalidduringdischarge.UNumberoffulldischargecyclesorSBatterycurrentaveragedbasedon100UDeratedavailable100UAccumulatedmissedchargeduetomultipledischargesoccurringbeforeafullchargehasoccurred%UBatteryrelativestateof%DatawordsarereturnedinLittleEndianformat(leastsignificantbitCumulativeUsageThebq78412providesinternalstorageforcumulativeusagedataduringnormaloperation.Thestoreddatacanberetrievedoverthecommunicationsinterfaceforysisbyanexternalreaderandusedforwarrantyysispurposes.Thesedataarestoredinvolatilememory.However,thestoreddataarebackeduponceadaytothenon-volatilememoryandarewrittenbacktothevolatilememoryonasubsequentpower-up.Thisretrievalonlyhappensifthedevicehasbeenactivated.Activationalsoprovidesastartpointforusagelogging.ActivationisdonebysettingDevConfig1[10]=Noneofthecountersroll-over,andaresaturatedto umvalueincaseof9givesthememorylocationsofthestoreddata.Thefollowingistheinformationthatisstored.AbuseThesecounttheamountoftimethatthebatteryhasspent mendedoperatingOnceevery6minutes,thebatteryischeckedforabuse.Theappropriatecounterincrementsifabuseisdetected.Eachcounterisof2bytesandcanstorevaluesfrom0to65535.Thispermitsa umtimeof273daystobeTheabusecountersOtCount:TimetemperaturewasaboveUtCount:TimetemperaturewasbelowOvCount:TimebatteryvoltagewasaboveUvCount:TimebatteryvoltagewasbelowOccCount:TimechargingcurrentwasaboveOcdCount:Timedischargingcurrentwasabove图6showsoperatingrangesandthresholdsforvoltage,temperatureandDepthofDischarge(DoD)These