Datasheet

GENERALDESCRIPTION
bq27510-G1
www.ti.com .....................................................................................................................................................................................................SLUS927–APRIL2009
Thebq27510accuratelypredictsthebatterycapacityandotheroperationalcharacteristicsofasingleLi-based
rechargeablecell.Itcanbeinterrogatedbyasystemprocessortoprovidecellinformation,suchas
state-of-charge(SOC),time-to-empty(TTE)andtime-to-full(TTF).
Informationisaccessedthroughaseriesofcommands,calledStandardCommands.Furthercapabilitiesare
providedbytheadditionalExtendedCommandsset.Bothsetsofcommands,indicatedbythegeneralformat
Command(),areusedtoreadandwriteinformationcontainedwithinthebq27510controlandstatusregisters,
aswellasitsdataflashlocations.Commandsaresentfromsystemtogaugeusingthebq27510’sI
2
Cserial
communicationsengine,andcanbeexecutedduringapplicationdevelopment,packmanufacture,or
end-equipmentoperation.
Cellinformationisstoredinthebq27510innon-volatileflashmemory.Manyofthesedataflashlocationsare
accessibleduringapplicationdevelopment.Theycannot,generally,beaccesseddirectlyduringend-equipment
operation.Accesstotheselocationsisachievedbyeitheruseofthebq27510’scompanionevaluationsoftware,
throughindividualcommands,orthroughasequenceofdata-flash-accesscommands.Toaccessadesireddata
flashlocation,thecorrectdataflashsubclassandoffsetmustbeknown.
Thebq27510provides96bytesofuser-programmabledataflashmemory,partitionedinto332-byteblocks:
ManufacturerInfoBlockA,ManufacturerInfoBlockB,andManufacturerInfoBlockC.Thisdataspaceis
accessedthroughadataflashinterface.Forspecificsonaccessingthedataflash,seesectionManufacturer
InformationBlocks.
Thekeytothebq27510’shigh-accuracygasgaugingpredictionisTexasInstrument’sproprietaryImpedance
Track™algorithm.Thisalgorithmusescellmeasurements,characteristics,andpropertiestocreate
state-of-chargepredictionsthatcanachievelessthan1%erroracrossawidevarietyofoperatingconditionsand
overthelifetimeofthebattery.
Thebq27510measurescharge/dischargeactivitybymonitoringthevoltageacrossasmall-valueseriessense
resistor(5mΩto20mΩtyp.)locatedbetweenthesystem’sVssandthebattery’sPACK–terminal.Whenacell
isattachedtothebq27510,cellimpedanceiscomputed,basedoncellcurrent,cellopen-circuitvoltage(OCV),
andcellvoltageunderloadingconditions.
Thebq27510externaltemperaturesensingisoptimizedwiththeuseofahighaccuracynegativetemperature
coefficient(NTC)thermistorwithR
25
=10.0kΩ±1%.B25/85=3435K±1%(suchasSemitecNTC103AT).The
bq27510canalsobeconfiguredtouseitsinternaltemperaturesensor.Whenanexternalthermistorisused,a
18.2kpullupresistorbetweenBT/TOUTandTSpinsisalsorequired.Thebq27510usestemperaturetomonitor
thebattery-packenvironment,whichisusedforfuelgaugingandcellprotectionfunctionality.
Tominimizepowerconsumption,thebq27510hasseveralpowermodes:NORMAL,SLEEP,HIBERNATE,and
BATINSERTCHECK.Thebq27510passesautomaticallybetweenthesemodes,dependinguponthe
occurrenceofspecificevents,thoughasystemprocessorcaninitiatesomeofthesemodesdirectly.Moredetails
canbefoundinSectionPowerModes.
NOTE:
FORMATTINGCONVENTIONSINTHISDOCUMENT:
Commands:italicswithparenthesesandnobreakingspaces,e.g.
RemainingCapacity().
DataFlash:italics,bold,andbreakingspaces,e.g.DesignCapacity.
Registerbitsandflags:bracketsanditalics,e.g.[TDA]
Dataflashbits:brackets,italicsandbold,e.g:[LED1]
Modesandstates:ALLCAPITALS,e.g.UNSEALEDmode.
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Not Recommended For New Designs