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scalededvfthreshold(sedvf)—address0x77
scalededv1threshold(sedv1)—address0x78
initialstandbyloadcurrent(islc)—address0x79
digitalmagnitudefilterandself-dischargevalues(dmfsd)—address0x7a
tapercurrent(taper)—address0x7b
bq27000,bq27200
SLUS556B–SEPTEMBER2004–REVISEDNOVEMBER2004
thisregistercontainsthescaledvalueofthethresholdforzerobatterycapacity.tocalculatethevalueto
程序,usethefollowingequation:
sedvf=designedvf(mv)/8–256
thisregistercontainsthescaledvalueofthevoltagewhenthebatteryhas6.25%remainingcapacity.whenthe
batteryreachesthisthresholdduringavaliddischarge,thedevicelearnsthefullbatterycapacity,includingthe
remaining6.25%.seethe
bqJUNIORCapacityLearning
sectionformoreinformationonthelearningcyclesof
thedevice.tocalculatethevaluetoprogram,usethefollowingequation:
sedv1=designedv1(mv)/8–256
thisregistercontainsthescaled,终止-设备-designstandbycurrent.onafullresetorpor,thisvalueis
transferredtothesiregisterandisusedtocalculatestandbytime-至-empty.thegaugelearnsanewstandby
loadifthedischargeactivityisabovetheDMFthresholdandlessthanorequalto2timestheinitialstandby
加载.
Acapacitylearningcycleisdisqualifiedifaveragecurrentislessthanorequalto2timestheinitialstandbyload
whentheedv1thresholdvoltageisreached.theequationforprogrammingthisvalueis:
islc=designstandbycurrent(毫安)*r
S
(m
Ω
)/7.14
whereR
S
isthevalueofthesenseresistorusedinthesystem.
BIT7BIT6BIT5BIT4BIT3BIT2BIT1BIT0
NAMEDMF[3]DMF[2]DMF[1]DMF[0]SD[3]SD[2]SD[1]SD[0]
dmf[3:0]
setsthedigitalmagnitudefilterthreshold.seethe
bqJUNIORDigitalMagnitudeFilter
sectionfor
moreinformationonthefunctionofthedmf.thevaluetobeprogrammedis:
dmf[3:0]=designthreshold/4.9
sd[3:0]
setstheself-dischargerate%/dayvalueat25
°
c.thevaluetobeprogrammedis:
sd[3:0]=1.61/designsd
nacisreducedwithanestimatedself-dischargecorrectiontoadjustfortheexpectedself-dischargeofthe
电池.thisestimationisperformedonlywhenthebatteryisnotbeingcharged.therateprogrammedin
eepromfordmfsddeterminestheself-dischargewhen20
°
C
≤
温度<30
°
c.theself-dischargeestimationis
doubledforeach10
°
cdecadehotterthanthe20-30
°
cdecade,uptoamaximumof16timestheprogrammed
rateforTEMP
≥
60
°
Candishalvedforeach10
°
cdecadecolderthanthe20-30
°
cdecade,downtoaminimum
of1/4ththeprogrammedratefortemp<0
°
c.theself-dischargeestimationisperformedbyreducingnacby
nac/512atatimeintervalthatachievesthedesiredestimation.ifdmfsdisprogrammedwith8decimal,这
自-dischargerateis0.195%perdayinthe20-30
°
cdecade.thisisaccomplishedbyreducingnacby
nac/512(100/512=0.195%)asingletimeevery23.3hours(0.195*24/23.3=0.2).iftemperaturerisesby
10
°
c,the0.195%nacreductionismadeevery11.65hoursfora0.4%perdayreduction.iftaper[7]=1,
capacityagingisenabled,andthereisanlmdreductionof0.01%(designcapacity/1024)everytimethereare
8nacself-dischargeestimatereductionswithoutchargingthebatterytofull.
thisregistercontainstheenablebitforthecapacityagingestimateandthechargetapercurrentvalue.这
tapercurrentvalue,inadditiontobatteryvoltage,isusedtodeterminewhenthebatteryhasreachedafull
chargestate.theequationforprogrammingthetapercurrentis:
taper[6-0]=designtapercurrent(毫安)*r
S
(m
Ω
)/228
µ
V
whereR
S
isthevalueofthesenseresistorusedinthesystem.
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