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6APPLICATION-SPECIFICINFORMATION
6.1BATTERYPROFILESTORAGEANDSELECTION
6.1.1GeneralProfileDescription
6.1.2ActivitiesUponPackInsertion
6.2APPLICATION-SPECIFICFLOWANDCONTROL
6.2.1SimpleBattery(bq27500Only)
bq27500
bq27501
System-SideImpedanceTrack™FuelGauge
SLUS785–SEPTEMBER2007
Whenabatterypackisremovedfromsystemequipmentthatimplementsthebq27500/01,thefuelgauge
willmaintainsomeofthebattery’sinformationincaseitisre-inserted.Thisway,theImpedanceTrack™
algorithmhasameansofrecoveringbattery-statusinformation,thereby,maintaininggood
State-of-Charge(SOC)estimates.
Twodefaultbatteryprofilesareavailabletostorebatteryinformation.Theyareusedtoprovidethe
ImpedanceTrack™algorithmwiththedefaultinformationontwopossiblebatterytypesexpectedtobe
usedwiththeend-equipment.Thesedefaultprofilescanbeusedtosupportbatteriesofdifferent
chemistry,samechemistrybutdifferentcapacities,orsamechemistrybutdifferentmodels.Default
profilesareprogrammedbytheend-equipmentmanufacturer.Notethatinthecaseofbq27500,onlyone
ofthedefaultprofilescanbeselected,andthisselectioncannotbechangedduringend-equipment
operation.
Inadditiontothedefaultprofiles,thebq27500/01maintainstwoabbreviatedprofiles.Thesetableshold
dynamicbatterydata,andkeeptrackofthestatusforuptotwoofthemostrecentbatteriesused.Inmost
casesthebq27500/01canadministrateinformationontworemovablebatterypacks.
6.1.2.1FirstOCVandImpedanceMeasurement
Atpower-uptheBAT_GDpinisinactive,sothatthesystemcannotobtainpowerfromthebattery(this
dependsonactualimplementation).Inthisstate,thebatteryisputinanopen-circuitcondition.Next,the
bq27500/1measuresitsfirstopen-circuitvoltage(OCV)viatheBATpin.FromtheOCV(SOC)table,the
SOCoftheinsertedbatteryisfound.ThentheBAT_GDpinismadeactive,andtheimpedanceofthe
insertedbatteryiscalculatedfromthemeasuredvoltageandtheloadcurrent:Z(SOC)=(OCV(SOC)–V
)/I.Thisimpedanceiscomparedwiththeimpedanceofthedynamicprofiles,PacknRa,anddefault
profiles,DefnRa,forthesameSOC(theletter"n"depictseithera"0"or"1").
6.1.2.2ReadingApplicationStatus
TheApplicationStatusdataflashlocationcontainscellprofilestatusinformation,andcanbereadusing
theApplicationStatus()ExtendedCommand(0x6a/0x6b).Thebitconfigurationofthisfunction/locationis
showninSection6.1.3.
Table6.1.3.ApplicationStatus()bitDefinitions.
Applicationbit7bit6bit5bit4bit3bit2bit1bit0
Configuration
Byte——————UNSUPBATLU_PROF
UNSUPBAT=Flagindicatinginsertedbatteryisnotsupportedinthecurrentcellprofiles.Truewhenset.bq27501only.
LU_PROF=Lastprofileusedbygasgauge.Cell0lastusedwhencleared.Cell1lastusedwhenset.Defaultis0.
Thebq27500supportsonlyonetypeofbatteryprofile.ThisprofileisstoredinboththeDef0RaandDef1
Raprofiles.Whenabatterypackisinsertedforthefirsttime,thedefaultprofileiscopiedintothePackn
Raprofiles.ThentheImpedanceTrack™algorithmbeginsgasgauging,regularlyupdatingPacknRaas
thebatteryisused.
Whenanexistingpackisremovedfromthebq27500andadifferent(orsame)packisinserted,cell
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