Datasheet

ReserveCap-mAh
ReserveCap-mWh
DsgCurrentThreshold
ChgCurrentThreshold
QuitCurrent,DsgRelaxTime,ChgRelaxTime,andQuitRelaxTime
bq27510-G1
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Table8.Constant-CurrentModelUsedWhenLoadMode=0(continued)
LoadSelectCurrentModelUsed
Value
4Designcapacity/5:CRatebasedoffofDesignCapacity/5oraC/5rateinmA.
5AtRate(mA):UsewhatevercurrentisinAtRate()
6User_Rate-mA:UsethevalueinUser_Rate().Thisgivesacompletelyuser-configurablemethod.
IfLoadMode=1(ConstantPower)thenthefollowingoptionsareavailable:
Table9.Constant-CurrentModelUsedWhenLoadMode=1
LoadSelectCurrentModelUsed
Value
0(default)Averagedischargecurrentfrompreviouscycle:Thereisaninternalregisterthatrecordstheaveragedischargecurrent
througheachentiredischargecycle.Thepreviousaverageisstoredinthisregister.
1Presentaveragedischargecurrent:Thisistheaveragedischargecurrentfromthebeginningofthisdischargecycle
untilpresenttime.
2Averagecurrent×voltage:basedofftheAverageCurrent()andVoltage().
3Current×voltage:basedoffofalow-pass-filteredversionofAverageCurrent()(τ=14s)andVoltage().
4Designenergy/5:CRatebasedoffofDesignEnergy/5oraC/5rateinmA.
5AtRate(10mW):UsewhatevercurrentisinAtRate()
6User_Rate-10mW:UsethevalueinUser_Rate()mW.Thisgivesacompletelyuser-configurablemethod.
ReserveCap-mAhdetermineshowmuchactualremainingcapacityexistsafterreaching0
RemainingCapacity(),beforeTerminateVoltageisreached.Ano-loadrateofcompensationisappliedtothis
reserve.
ReserveCap-mWhdetermineshowmuchactualremainingcapacityexistsafterreaching0AvailableEnergy(),
beforeTerminateVoltageisreached.Ano-loadrateofcompensationisappliedtothisreservecapacity.
Thisregisterisusedasathresholdbymanyfunctionsinthebq27510todetermineifactualdischargecurrentis
flowingintooroutofthecell.Thethresholdshouldbesetlowenoughtobebelowanynormalapplicationload
currentbuthighenoughtopreventnoiseordriftfromaffectingthemeasurement.
Thisregisterisusedasathresholdbymanyfunctionsinthebq27510todetermineifactualchargecurrentis
flowingintooroutofthecell.Thethresholdshouldbesetlowenoughtobebelowanynormalchargecurrentbut
highenoughtopreventnoiseordriftfromaffectingthemeasurement.
TheQuitCurrentisusedaspartoftheImpedanceTrack™algorithmtodeterminewhenthebq27510enters
relaxationmodefromacurrentflowingmodeineitherthechargedirectionorthedischargedirection.Thevalue
ofQuitCurrentshouldbeabovethestandbycurrentofthesystem.
Thefollowingcriteriamustbemettoenterrelaxationmode
|AverageCurrent()|<|QuitCurrent|forDsgRelaxTime(ifinCHGmode)orChgRelaxTime(ifinDSG
mode).
Afterabout30minutesinrelaxationmode,thebq27510attemptstotakeaccurateOCVreadings.Anadditional
requirementofdV/dt4µV/secisrequiredforthebq27510toperformQmaxupdates.Theseupdatesareusedin
theImpedanceTrack™algorithms.ItiscriticalthatthebatteryvoltageberelaxedduringOCVreadingstoand
thatthecurrentisnotbehigherthanC/20whenattemptingtogointorelaxationmode.
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