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lastmeasureddischargeregisters(lmdl/lmdh)—address0x12/0x13
averagecurrentregisters(ail/aih)—address0x14/0x15
时间-至-emptyregisters(ttel/tteh)—address0x16/0x17
时间-至-fullregisters(ttfl/ttfh)—address0x18/0x19
standbycurrentregisters(sil/sih)—address0x1a/0x1b
standbytime-至-emptyregisters(sttel/stteh)—address0x1c/0x1d
bq27000,bq27200
SLUS556B–SEPTEMBER2004–REVISEDNOVEMBER2004
lastmeasureddischargeisthemeasureddischargecapacityofthebatteryfromfulltoempty.lmdisupdated
onavalidlearningcycle,whichoccurswhenthebatteryreachestheedv1levelwhilethevdqbitisset.itis
usedwithnactocalculaterelativestate-的-承担(rsoc).thehostsystemhasread-onlyaccesstothis
registerpair.lmdisreportedinunitsof3.57µvhpercount.
thisregisterpairreportsthemagnitudeoftheaveragecurrentthroughthesenseresistor.thevalueisreported
witharesolutionof3.57
µ
vpercount.usethefollowingequationtoconvertthevaluetoma,wherer
S
isthe
senseresistorvalueinmilliohms:
averagecurrent=(256*aih+ail)*3.57/r
S
thecurrentreportedisanaverageoverthelast5.12seconds.thehostsystemhasread-onlyaccesstothis
registerpair.
thisregisterpairreportscalculatedtime-至-emptyatthemeasureddischargerate.thisvalueisbasedonthe
temperatureanddischargeratecompensatedavailablechargeandtheaveragecurrent.theequationto
calculatetteis:
tte=60*cact/ai
tteisreportedinminutes.thehostsystemhasread-onlyaccesstothisregisterpair.
thisregisterpairreportscalculatedtime-至-fullatthemeasuredchargerate.thetimecomputedattheaverage
currentchargerateisextendedby50%toestimatetheeffectofthecurrenttaper.ttfisreportedinminutes.
theequationforttfis:
ttf=60*1.50*(lmd-nac)/ai
thehostsystemhasread-onlyaccesstothisregisterpair.
thisregisterpairreportsmeasuredstandbycurrentthroughthesenseresistor.thestandbycurrentisan
adaptivemeasurement.initially,theregisterpairreportsthestandbycurrentprogrammedineepromandafter
spendingsometimeinstandby,theregisterpairreportsthemeasuredstandbycurrent.theregistervalueis
updatedevery5.12secondswhenthemeasuredcurrentisabovethedmfthresholdandislessthanorequalto
2xtheinitialprogrammedstandbycurrentvalue.eachnewsivalueiscomputedasfollows:
SI
新
=(15/16)*si
OLD
+(1/16)*ai
Thisfilterfunctionallowsthereportedstandbycurrenttoshifttowardstheactualmeasuredcurrentwithatime
constantofapproximately67seconds.thevalueisreportedwitharesolutionof3.57
µ
vperbit.usethe
followingequationtoconvertthevaluetoma,wherer
S
isthesenseresistorvalueinmilliohms:
standbyloadcurrent=(256*sih+sil)*(3.57/r
S
)
thehostsystemhasread-onlyaccesstothisregisterpair.
thisregisterpairreportscalculatedtime-至-emptyatthemeasuredstandbycurrentvalue.thisvalueisbasedon
thenominalavailablechargeandthestandbycurrent.stteisreportedinminutes.stteiscalculatedby:
stte=60*nac/si
thehostsystemhasread-onlyaccesstothisregisterpair.
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