BQ24751B Datasheet by Texas Instruments

1FEATURES
APPLICATIONS
DESCRIPTION
ACOP
bq24751B
28LDQFN
TOP VIEW
LEARN
SRN
BAT
CELLS
SRP
SRSET
IADAPT
ACDRV
ACSET
CHGEN
ACN
ACP
ACDET
PVCC
BTST
HIDRV
REGN
PH
LODRV
PGND
OVPSET
AGND
VREF
VADJ
VDAC
ACGOOD
BATDRV
1
2
3
4
5
6
7
8 9 10 11 12 13 14
15
16
17
18
19
20
21
27 26 25 24 23 22
28
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
Host-ControlledMulti-ChemistryBatteryChargerwithLowI
q
andSystemPowerSelector
–<10µAOff-StateBatteryDischargeCurrent
2•NMOS-NMOSSynchronousBuckConverter–<1.5mAOff-StateInputQuiescentCurrent
with300kHzFrequencyand>95%Efficiency
•30-nsMinimumDriverDead-timeand99.5%•NotebookandUltra-MobileComputers
MaximumEffectiveDutyCycle•PortableDataCaptureTerminals
•High-AccuracyVoltageandCurrentRegulation•PortablePrinters
–±0.5%ChargeVoltageAccuracy•MedicalDiagnosticsEquipment
–±3%ChargeCurrentAccuracy•BatteryBayChargers
–±3%AdapterCurrentAccuracy•BatteryBack-upSystems
–±2%InputCurrentSenseAmpAccuracy
•Integration
–AutomaticSystemPowerSelectionFromThebq24751Bisahigh-efficiency,synchronous
AC/DCAdapterorBatterybatterychargerwithintegratedcompensationand
–InternalLoopCompensationsystempowerselectorlogic,offeringlowcomponent
countforspace-constrainedmulti-chemistrybattery
–InternalSoftStartchargingapplications.Ratiometricchargecurrentand
•Safetyvoltageprogrammingallowsgorhighregulation
–ProgrammableInputOvervoltageaccuracies,andcanbeeitherhardwiredwithresistors
Protection(OVP)orprogrammedbythesystempower-management
microcontrollerusingaDACorGPIOs.
–DynamicPowerManagement(DPM)with
StatusIndicatorThebq24751Bchargestwo,three,orfourseriesLi+
cells,supportingupto10Aofchargecurrent,andis
–ProgrammableInrushAdapterPoweravailableina28-pin,5x5-mmthinQFNpackage.
(ACOP)andOvercurrent(ACOC)Limits
–Reverse-ConductionProtectionInputFET
•SupportsTwo,Three,orFourLi+Cells
•5–24VAC/DC-AdapterOperatingRange
•AnalogInputswithRatiometricProgramming
viaResistorsorDAC/GPIOHostControl
–ChargeVoltage(4-4.512V/cell)
–ChargeCurrent(upto10A,with10-mΩ
SenseResistor)
–AdapterCurrentLimit(DPM)
•StatusandMonitoringOutputs
–AC/DCAdapterPresentwithProgrammable
VoltageThreshold
–CurrentDrawnfromInputSource
•BatteryLearnCycleControl
•SupportsAnyBatteryChemistry:Li+,NiCd,
NiMH,LeadAcid,etc.
•ChargeEnable
•28-pin,5x5-mmQFNpackage
•EnergyStarLowIq
1
Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsofTexas
Instrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.
2Alltrademarksarethepropertyoftheirrespectiveowners.
PRODUCTIONDATAinformationiscurrentasofpublicationdate.Copyright©2008–2009,TexasInstrumentsIncorporated
ProductsconformtospecificationsperthetermsoftheTexas
Instrumentsstandardwarranty.Productionprocessingdoesnot
necessarilyincludetestingofallparameters.
l TEXAS INSTRUMENTS Am
DESCRIPTION(CONTINUED)
VREF
RAC
0.010 Ω
RSR
0.010 Ω
Q2 (ACFET)
SI4435
Q3(BATFET)
SI4435
N
P P
ACN
ACP
/ACDRV
ACDET
/ACGOOD
SRSET
ACSET
VREF
CELLS
/CHGEN
VDAC
VADJ
ADC IADAPT
HOST
PVCC
/BATDRV
HIDRV
N
PH
BTST
REGN
LODRV
PGND
SRP
SRN
P
PACK+
PACK-
SYSTEM
ADAPTER +
ADAPTER -
/ACGOOD
AGND
bq24751B
2.2 µF
C1
432 kΩ
1% 66.5 kΩ
1%
R1
R2
10 kΩ
R5
0.1 µF
C4
100 pF
C5
0.1 µF
C8
Q4
FDS6680A
Q5
FDS6680A
0.1 µF
C9
L1
8.2 µH
D1
BAT54
1µF
C10
BAT
OVPSET
422 kΩ
1%
R3
71 kΩ
1%
R4
LEARN
ACOP
Q1 (ACFET)
SI4435
10 µF
C6
C15
0.1 µF
C16
0.47 µF
0.1 µF
C2 C3
2 Ω
R10
0.1 µF
PowerPad
10 µF
C7
10 µF
C12
C14
0.1 µF
C13
0.1 µF
C11
10 µF
GPIO
DAC
DAC
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
Thesedeviceshavelimitedbuilt-inESDprotection.Theleadsshouldbeshortedtogetherorthedeviceplacedinconductivefoam
duringstorageorhandlingtopreventelectrostaticdamagetotheMOSgates.
Thebq24751Bcontrolsexternalswitchestopreventbatterydischargebacktotheinput,connecttheadapterto
thesystem,andtoconnectthebatterytothesystemusing6-Vgatedrivesforbettersystemefficiency.For
maximumsystemsafety,inrush-powerlimitingprovidesinstantaneousresponsetohighinputvoltagemultiplied
bycurrent.ThisACOverpowerprotection(ACOP)featurelimitstheinput-switchpowertotheprogrammedlevel
ontheACOPpin,andlatchesoffifthehigh-powerconditionpersiststopreventoverheating.
Thebq24751BfeaturesDynamicPowerManagement(DPM)andinputpowerlimiting.Thesefeaturesreduce
batterychargecurrentwhentheinputpowerlimitisreachedtoavoidoverloadingtheACadapterwhensupplying
theloadandthebatterychargersimultaneously.Ahighly-accuratecurrent-senseamplifierenablesprecise
measurementofinputcurrentfromtheACadaptertomonitortheoverallsystempower.
(1)Pull-uprailcouldbeeitherVREForothersystemrail.
(2)SRSET/ACSETcouldcomefromeitherDACorresistordividers.
VIN=20V,VBAT=3-cellLi-Ion,Icharge=3A,Iadapter_limit=4A
Figure1.TypicalSystemSchematic,VoltageandCurrentProgrammedbyDAC
2SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
VREF
RAC
0.010 Ω
RSR
0.010 Ω
Q2 (ACFET)
SI4435
Q3(BATFET)
SI4435
N
P P
ACN
ACP
/ACDRV
ACDET
/ACGOOD
SRSET
ACSET
VREF
CELLS
/CHGEN
VDAC
VADJ
ADC IADAPT
HOST
PVCC
/BATDRV
HIDRV
N
PH
BTST
REGN
LODRV
PGND
SRP
SRN
P
PACK+
PACK-
SYSTEM
ADAPTER +
ADAPTER -
/ACGOOD
AGND
bq24751B
2.2 µF
C1
10 kΩ
R5
0.1 µF
C4
100 pF
C5
0.1 µF
C8
Q4
FDS6680A
Q5
FDS6680A
0.1 µF
C9
L1
8.2 µH
D1
BAT54
1µF
C10
BAT
OVPSET
422 kΩ
1%
R3
71 kΩ
1%
R4
LEARN
ACOP
Q1 (ACFET)
SI4435
10 µF
C6
C15
0.1 µF
C16
0.47 µF
0.1 µF
C2 C3
2 Ω
R10
0.1 µF
PowerPad
10 µF
C7
10 µF
C12
C14
0.1 µF
C13
0.1 µF
C11
10 µF
GPIO
VREF
VREF
100 kΩ
R8
66.5 kΩ
R9
100 kΩ
R7
43 kΩ
R11
VREF
REGN
432 kΩ
1% 66.5 kΩ
1%
R1
R2
PACKAGETHERMALDATA
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
(1)Pull-uprailcouldbeeitherVREForothersystemrail.
(2)SRSET/ACSETcouldcomefromeitherDACorresistordividers.
VIN=20V,VBAT=3-cellLi-Ion,Icharge=3A,Iadapter_limit=4A
Figure2.TypicalSystemSchematic,VoltageandCurrentProgrammedbyResistor
ORDERINGINFORMATION
ORDERINGNUMBER
PARTNUMBERPACKAGEQUANTITY
(TapeandReel)
bq24751BRHDR3000
bq24751B28-PIN5x5mmQFNbq24751BRHDT250
TA=70°CDERATINGFACTOR
PACKAGEθJAPOWERRATINGABOVETA=70°C
QFN–RHD(1)(2)39°C/W2.36W0.028W/°C
(1)Forthemostcurrentpackageandorderinginformation,seethePackageOptionAddendumattheendofthisdocument,orseetheTI
Websiteatwww.ti.com.
(2)ThisdataisbasedonusingtheJEDECHigh-KboardandtheexposeddiepadisconnectedtoaCupadontheboard.Thisis
connectedtothegroundplanebya2x3viamatrix.
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback3
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
Table1.PINFUNCTIONS–28-PINQFN
PINDESCRIPTION
NAMENO.
CHGEN 1Chargeenableactive-lowlogicinput.LOenablescharge.HIdisablescharge.
Adaptercurrentsenseresistor,negativeinput.A0.1-µFceramiccapacitorisplacedfromACNtoACPtoprovide
ACN2differential-modefiltering.Anoptional0.1-µFceramiccapacitorisplacedfromACNpintoAGNDforcommon-mode
filtering.
Adaptercurrentsenseresistor,positiveinput.A0.1-µFceramiccapacitorisplacedfromACNtoACPtoprovide
ACP3differential-modefiltering.A0.1-µFceramiccapacitorisplacedfromACPpintoAGNDforcommon-modefiltering.
ACadaptertosystem-switchdriveroutput.ConnectdirectlytothegateoftheACFETP-channelpowerMOSFETand
thereverseconductionblockingP-channelpowerMOSFET.ConnectbothFETsascommon-source.Connectthe
ACFETdraintothesystem-loadside.ThePVCCshouldbeconnectedtothecommon-sourcenodetoensurethatthe
driverlogicisalwaysactivewhenneeded.Ifneeded,anoptionalcapacitorfromgatetosourceoftheACFETisusedto
ACDRV4slowdowntheONandOFFtimes.Theinternalgatedriveisasymmetrical,allowingaquickturn-offandslowerturn-on
inadditiontotheinternalbreak-before-makelogicwithrespecttotheBATDRV.Theoutputgoesintolinearregulation
modewhentheinputsensedcurrentexceedstheACOCthreshold.ACDRVislatchedoffafterACOPvoltageexceeds2
V,toprotectthechargingsystemfromanACFET-overpowercondition.
Adapterdetectedvoltagesetinput.Programtheadapterdetectthresholdbyconnectingaresistordividerfromadapter
ACDET5inputtoACDETpintoAGNDpin.AdaptervoltageisdetectedifACDET-pinvoltageisgreaterthan2.4V.TheIADAPT
currentsenseamplifierisactivewhentheACDETpinvoltageisgreaterthan0.6V.
Adaptercurrentsetinput.ThevoltageratioofACSETvoltageversusVDACvoltageprogramstheinputcurrent
regulationset-pointduringDynamicPowerManagement(DPM).ProgrambyconnectingaresistordividerfromVDACto
ACSET6ACSETtoAGND;orbyconnectingtheoutputofanexternalDACtotheACSETpinandconnecttheDACsupplytothe
VDACpin.
Inputpowerlimitsetinput.ProgramtheinputoverpowertimeconstantbyplacingaceramiccapacitorfromACOPto
AGND.Thecapacitorsetsthetimethattheinputcurrentlimit,ACOC,canbesustainedbeforeexceedingthe
ACOP7power-MOSFETpowerlimit.WhentheACOPvoltageexceeds2V,thentheACDRVlatchesofftoprotectthecharge
systemfromanoverpowercondition,ACOP.ResetlatchbytogglingACDETorPVCC_UVLO.
Setinputovervoltageprotectionthreshold.ChargeisdisabledandACDRVisturnedoffifadapterinputvoltageis
higherthantheOVPSETprogrammedthreshold.Inputovervoltage,ACOV,disableschargeandACDRVwhen
OVPSET8OVPSET>3.1V.ACOVdoesnotlatch.Programtheovervoltageprotectionthresholdbyconnectingaresistordivider
fromadapterinputtoOVPSETpintoAGNDpin.
Analogground.Groundconnectionforlow-currentsensitiveanaloganddigitalsignals.OnPCBlayout,connecttothe
AGND9analoggroundplane,andonlyconnecttoPGNDthroughthePowerPadunderneaththeIC.
3.3-Vregulatedvoltageoutput.Placea0.1-µFceramiccapacitorfromVREFtoAGNDpinclosetotheIC.Thisvoltage
VREF10couldbeusedforratiometricprogrammingofvoltageandcurrentregulation.Donotapplyaexternalvoltagesourceon
thispin.
Chargevoltagesetreferenceinput.ConnecttheVREForexternalDACvoltagesourcetotheVDACpin.Battery
voltage,chargecurrent,andinputcurrentareprogrammedasaratiooftheVDACpinvoltageversustheVADJ,
VDAC11SRSET,andACSETpinvoltages,respectively.PlaceresistordividersfromVDACtoVADJ,SRSET,andACSETpins
toAGNDforprogramming.ADACcouldbeusedbyconnectingtheDACsupplytoVDACandconnectingtheoutputto
VADJ,SRSET,orACSET.
Chargevoltagesetinput.ThevoltageratioofVADJvoltageversusVDACvoltageprogramsthebatteryvoltage
regulationset-point.ProgrambyconnectingaresistordividerfromVDACtoVADJ,toAGND;or,byconnectingthe
VADJ12outputofanexternalDACtoVADJ,andconnecttheDACsupplytoVDAC.VADJconnectedtoREGNprogramsthe
defaultof4.2Vpercell.
Validadapteractive-lowdetectlogicopen-drainoutput.PulledlowwhenInputvoltageisaboveprogrammedACDET.
ACGOOD 13Connecta10-kΩpullupresistorfromACGOODtoVREF,ortoadifferentpullup-supplyrail.
Batterytosystemswitchdriveroutput.GatedriveforthebatterytosystemloadBATPMOSpowerFETtoisolatethe
systemfromthebatterytopreventcurrentflowfromthesystemtothebattery,whileallowingalowimpedancepath
frombatterytosystemandwhiledischargingthebatterypacktothesystemload.Connectthispindirectlytothegateof
BATDRV14theinputBATP-channelpowerMOSFET.ConnectthesourceoftheFETtothesystemloadvoltagenode.Connectthe
drainoftheFETtothebatterypackpositivenode.Anoptionalcapacitorisplacedfromthegatetothesourcetoslow
downtheswitchingtimes.Theinternalgatedriveisasymmetricaltoallowaquickturn-offandslowerturn-on,inaddition
totheinternalbreak-before-makelogicwithrespecttoACDRV.
Adaptercurrentsenseamplifieroutput.IADAPTvoltageis20timesthedifferentialvoltageacrossACP-ACN.Placea
IADAPT15100-pForlessceramicdecouplingcapacitorfromIADAPTtoAGND.
Chargecurrentsetinput.ThevoltageratioofSRSETvoltageversusVDACvoltageprogramsthechargecurrent
SRSET16regulationset-point.ProgrambyconnectingaresistordividerfromVDACtoSRSETtoAGND;orbyconnectingthe
outputofanexternalDACtoSRSETpinandconnecttheDACsupplytoVDACpin.
Batteryvoltageremotesense.DirectlyconnectakelvinsensetracefromthebatterypackpositiveterminaltotheBAT
BAT17pintoaccuratelysensethebatterypackvoltage.Placea0.1-µFcapacitorfromBATtoAGNDclosetotheICtofilter
high-frequencynoise.
4SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
ABSOLUTEMAXIMUMRATINGS
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
Table1.PINFUNCTIONS–28-PINQFN(continued)
PINDESCRIPTION
NAMENO.
Chargecurrentsenseresistor,negativeinput.A0.1-µFceramiccapacitorisplacedfromSRNtoSRPtoprovide
SRN18differential-modefiltering.Anoptional0.1-µFceramiccapacitorisplacedfromSRNpintoAGNDforcommon-mode
filtering.
Chargecurrentsenseresistor,positiveinput.A0.1-µFceramiccapacitorisplacedfromSRNtoSRPtoprovide
SRP19differential-modefiltering.A0.1-µFceramiccapacitorisplacedfromSRPpintoAGNDforcommon-modefiltering.
CELLS202,3or4cellsselectionlogicinput.Logiclowprograms3cell.Logichighprograms4cell.Floatingprograms2cell.
Learnmodelogicinputcontrolpin—logichightooverridesystemselectorwhenadapterispresent,thebatteryis
dischargedtorecalibratethebattery-packgasgauge.WhenadapterispresentandLEARNishigh,batterychargingis
disabled,theadapterisdisconnected(ACDRVisoff),andthebatteryisconnectedtosystem(BATDRVison).SystemLEARN21selectorautomaticallyswitchestoadapterifbatteryisdischargedbelowLOWBAT(3V).Whenadapterispresentand
LEARNislow,theadapterisconnectedtosysteminnormalselectorlogic(ACDRVisonandBATDRVisoff),allowing
batterycharging.Ifadapterisnotpresent,thebatteryisalwaysconnectedtothesystem(ACDRVisoffandBATDRVis
on).
Powerground.Groundconnectionforhigh-currentpowerconverternode.OnPCBlayout,connectdirectlytosourceof
PGND22low-sidepowerMOSFET,togroundconnectionofinputandoutputcapacitorsofthecharger.OnlyconnecttoAGND
throughthePowerPadunderneaththeIC.
LODRV23PWMlowsidedriveroutput.Connecttothegateofthelow-sidepowerMOSFETwithashorttrace.
PWMlowsidedriverpositive6-Vsupplyoutput.Connecta1-µFceramiccapacitorfromREGNtoPGND,closetothe
REGN24IC.Useforhigh-sidedriverbootstrapvoltagebyconnectingasmall-signalSchottkydiodefromREGNtoBTST.REGN
isdisabledwhenCHGENishigh.
PWMhighsidedrivernegativesupply.Connecttothephaseswitchingnode(junctionofthelow-sidepowerMOSFET
PH25drain,high-sidepowerMOSFETsource,andoutputinductor).Connectthe0.1-µFbootstrapcapacitorfromfromPHto
BTST.
HIDRV26PWMhighsidedriveroutput.Connecttothegateofthehigh-sidepowerMOSFETwithashorttrace.
PWMhighsidedriverpositivesupply.Connecta0.1-µFbootstrapceramiccapacitorfromBTSTtoPH.Connectasmall
BTST27bootstrapSchottkydiodefromREGNtoBTST.
ICpowerpositivesupply.Connecttothecommon-source(diode-OR)point:sourceofhigh-sideP-channelMOSFETand
PVCC28sourceofreverse-blockingpowerP-channelMOSFET.Placea0.1-µFceramiccapacitorfromPVCCtoPGNDpinclose
totheIC.
ExposedpadbeneaththeIC.AGNDandPGNDstar-connectedonlyatthePowerPadplane.AlwayssolderPowerPad
PowerPadtotheboard,andhaveviasonthePowerPadplaneconnectingtoAGNDandPGNDplanes.Italsoservesasathermal
padtodissipatetheheat.
overoperatingfree-airtemperaturerange(unlessotherwisenoted)(1)(2)
VALUEUNIT
PVCC,ACP,ACN,SRP,SRN,BAT,BATDRV,ACDRV –0.3to30
PH–1to30
REGN,LODRV,VREF,VDAC,VADJ,ACSET,SRSET,ACDET,ACOP,
Voltagerange–0.3to7V
CHGEN,CELLS,STAT,ACGOOD,LEARN,OVPSET
VREF,IADAPT–0.3to3.6
BTST,HIDRVwithrespecttoAGNDandPGND–0.3to36
MaximumdifferencevoltageACP–ACN,SRP–SRN,AGND–PGND–0.5to0.5V
Junctiontemperaturerange,TJ–40to155°C
Storagetemperaturerange,Tstg–55to155
(1)Stressesbeyondthoselistedunderabsolutemaximumratingsmaycausepermanentdamagetothedevice.Thesearestressratings
only,andfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunderrecommendedoperating
conditionsisnotimplied.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability.
(2)AllvoltagesarewithrespecttoGNDifnotspecified.Currentsarepositiveinto,negativeoutofthespecifiedterminal.ConsultPackaging
Sectionofthedatabookforthermallimitationsandconsiderationsofpackages.
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback5
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
RECOMMENDEDOPERATINGCONDITIONS
ELECTRICALCHARACTERISTICS
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
overoperatingfree-airtemperaturerange(unlessotherwisenoted)
MINNOMMAXUNIT
PH–124V
PVCC,ACP,ACN,SRP,SRN,BAT,BATDRV,ACDRV 024V
REGN,LODRV06.5V
VoltagerangeVDAC,IADAPT03.6V
VREF3.3V
ACSET,SRSET,TS,ACDET,ACOP,CHGEN,CELLS,ACGOOD,LEARN, V
05.5
OVPSET
VADJ06.5V
BTST,HIDRVwithrespecttoAGNDandPGND030V
AGND,PGND–0.30.3V
MaximumdifferenceACP–ACN,SRP–SRN–0.30.3V
voltage
Junctiontemperaturerange,TJ–40125°C
Storagetemperaturerange,Tstg–55150
7V≤VPVCC≤24V,0°C<TJ<125°C,typicalvaluesareatTA=25°C,withrespecttoAGND(unlessotherwisenoted)
PARAMETERTESTCONDITIONSMINTYPMAXUNIT
OPERATINGCONDITIONS
VPVCC_OPPVCCInputvoltageoperatingrange524V
CHARGEVOLTAGEREGULATION
VBAT_REG_RNGBATvoltageregulationrange4-4.512Vpercell,times2,3,4cells818.048V
VVDAC_OPVDACreferencevoltagerange2.63.6V
VADJ_OPVADJvoltagerange0REGNV
8V,8.4V,9.024V–0.5%0.5%
Chargevoltageregulationaccuracy12V,12.6V,13.536V–0.5%0.5%
16V,16.8V,18.048V–0.5%0.5%
ChargevoltageregulationsettodefaultVADJconnectedtoREGN,8.4V,12.6V,16.8V–0.5%0.5%
to4.2Vpercell
CHARGECURRENTREGULATION
VIREG_CHGChargecurrentregulationdifferentialVIREG_CHG=VSRP–VSRN0100mV
voltagerange
VSRSET_OPSRSETvoltagerange0VDACV
VIREG_CHG=40–100mV–3%3%
VIREG_CHG=20mV–5%5%
ChargecurrentregulationaccuracyVIREG_CHG=5mV–25%25%
VIREG_CHG=1.5mV(VBAT>4V)–33%33%
INPUTCURRENTREGULATION
VIREG_DPMAdaptercurrentregulationdifferentialVIREG_DPM=VACP–VACN0100mV
voltagerange
VACSET_OPACSETvoltagerange0VDACV
VIREG_DPM=40–100mV–3%3%
VIREG_DPM=20mV–5%5%
InputcurrentregulationaccuracyVIREG_DPM=5mV–25%25%
VIREG_DPM=1.5mV–33%33%
VREFREGULATOR
VVREF_REGVREFregulatorvoltageVACDET>0.6V,0-30mA3.2673.33.333V
IVREF_LIMVREFcurrentlimitVVREF=0V,VACDET>0.6V3580mA
6SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
ELECTRICALCHARACTERISTICS(continued)
7V≤VPVCC≤24V,0°C<TJ<125°C,typicalvaluesareatTA=25°C,withrespecttoAGND(unlessotherwisenoted)
PARAMETERTESTCONDITIONSMINTYPMAXUNIT
REGNREGULATOR
VREGN_REGREGNregulatorvoltageVACDET>0.6V,0-75mA,PVCC>10V5.65.96.2V
IREGN_LIMREGNcurrentlimitVREGN=0V,VACDET>0.6V90135mA
ADAPTERCURRENTSENSEAMPLIFIER
VACP/N_OPInputcommonmoderangeVoltageonACP/ACN024V
VIADAPTIADAPToutputvoltagerange02
IIADAPTIADAPToutputcurrent01mA
AIADAPTCurrentsenseamplifiervoltagegainAIADAPT=VIADAPT/VIREG_DPM20V/V
VIREG_DPM=40–100mV–2%2%
VIREG_DPM=20mV–3%3%
AdaptercurrentsenseaccuracyVIREG_DPM=5mV–25%25%
VIREG_DPM=1.5mV–33%33%
IIADAPT_LIMOutputcurrentlimitVIADAPT=0V1mA
CIADAPT_MAXMaximumoutputloadcapacitanceForstabilitywith0mAto1mAload100pF
ACDETCOMPARATOR
VACDET_CHGACDETadapter-detectrisingthresholdMinvoltagetoenablecharging,VACDETrising2.3762.402.424V
VACDET_CHG_HYSACDETfallinghysteresisVACDETfalling40mV
ACDETrisingdeglitchVACDETrising518700908ms
ACDETfallingdeglitchVACDETfalling7911ms
VACDET_BIASACDETenable-biasrisingthresholdMinvoltagetoenableallbias,VACDETrising0.560.620.68V
VACDET_BIAS_HYSAdapterpresentfallinghysteresisVACDETfalling20mV
ACDETrisingdeglitchVACDETrising10µs
ACDETfallingdeglitchVACDETfalling10µs
PVCC/BATCOMPARATOR(REVERSEDISCHARGINGPROTECTION)
VPVCC-BAT_OPDifferentialVoltagefromPVCCtoBAT–2024V
VPVCC-BAT_FALLPVCCtoBATfallingthresholdVPVCC–VBATtoturnoffACFET140185240mV
VPVCC-BAT__HYSPVCCtoBAThysteresis50mV
PVCCtoBATRisingDeglitchVPVCC–VBAT>VPVCC-BAT_RISE7911ms
PVCCtoBATFallingDeglitchVPVCC–VBAT<VPVCC-BAT_FALL6µs
INPUTUNDERVOLTAGELOCK-OUTCOMPARATOR(UVLO)
UVLOACUndervoltagerisingthresholdMeasuredonPVCC3.544.5V
UVLO(HYS)ACUndervoltagehysteresis,falling260mV
ACLOWVOLTAGECOMPARATOR(ACLOWV)
AClowvoltagerisingthreshold3.6
VACLOWVMeasureonACPpinV
AClowvoltagefallingthreshold3
ACN/BATCOMPARATOR
VACN-BAT_FALLACNtoBATfallingthresholdVACN–VBATtoturnonBATDRV175285340mV
VACN-BAT_HYSACNtoBAThysteresis50mV
ACNtoBATrisingdeglitchVACN–VBAT>VACN-BAT_RISE20µs
ACNtoBATfallingdeglitchVACN–VBAT<VACN-BAT_FALL6µs
BATOVERVOLTAGECOMPARATOR
VOV_RISEOvervoltagerisingthresholdAspercentageofVBAT_REG104%
VOV_FALLOvervoltagefallingthresholdAspercentageofVBAT_REG102%
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback7
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
ELECTRICALCHARACTERISTICS(continued)
7V≤VPVCC≤24V,0°C<TJ<125°C,typicalvaluesareatTA=25°C,withrespecttoAGND(unlessotherwisenoted)
PARAMETERTESTCONDITIONSMINTYPMAXUNIT
BATSHORT(UNDERVOLTAGE)COMPARATOR
VBAT_SHORT_FALLBATshortfallingthresholdVBATfalling2.7552.93.045V/cell
VBAT_SHORT_HYSBATshorthysteresisVBATrising250mV/cell
VBAT>VBAT_SHORT+VBAT_SHORT_HYS
BATshortrisingdeglitch1.5
Detectiondelays
BATshortfallingdeglitchVBAT<VBAT_SHORT1.5
BATSHORTEXITdelaytoturnonLEARN=HIGH600ms
BATFETandturnoffACFET
BATSHORTENTRYdelaytoturnoffLEARN=HIGH10µs
BATFETandturnonACFET
CHARGEOVERCURRENTCOMPARATOR
VOCChargeovercurrentfallingthresholdAspercentageofIREG_CHG145%
OCPFloorMinimumcurrentLimit(SRP-SRN)50mV
fallingthreshold0.1xSRSET/VDACfalling33.75mV
OCPThresholdrisingthreshold0.1xSRSET/VDACrising42.5mV
CHARGEUNDERCURRENTCOMPARATOR(SYNCHRONOUSTONON-SYNCHRONOUSTRANSITION)
VISYNSET_FALLChargeundercurrentfallingthresholdChangingfromsynchronoustonon-sysnchronous9.751316.25mV
VISYNSET_HYSChargeundercurrentrisinghysteresis8mV
Chargeundercurrent,falling-current20
deglitchVIREG_DPM<VISYNSETµs
Chargeundercurrent,rising-current640
deglitch
INPUTOVERPOWERCOMPARATOR(ACOP)
VACOCACOCGainforinitialACOCcurrentBegins700msafterACDET,%
limitlimit(PercentageofprogrammedInputcurrentlimitedtothisthresholdforfault150VIREG_DPM
VIREG_DPM)protection
MaximumACOCinputcurrentlimitInternallylimitedceiling,
VACOC_CEILING100mV
(VACP–VACN)maxVACOC_MAX=(VACP–VACN)max
ACOPLatchBlankoutTimewithACOCBegins700msafterACDET2
active(doesnotallowACOPlatch-off,andnoACOPms
(begins700msafterACDET)sourcecurrent)
ACOPpinlatch-offthresholdvoltage
VACOP(SeeACOPinTerminalFunctions1.9522.05V
table)
CurrentsourceonwheninACOClimit.Functionof
GainforACOPSourceCurrentwhenin
KACOPvoltageacrosspowerFET18µA/V
ACOCIACOP_SOURCE=KACOP×(VPVCC-VACP)
ACOPSinkCurrentwhennotinACOC
IACOP_SINKACOPLatchisresetbygoingbelowCurrentsinkonwhennotinACOC5µA
ACDETorUVLO
VACN-SHORTACNShortprotectionthresholdlatchingACN<2.4V,ACDET>2.4V2.4V
INPUTOVERVOLTAGECOMPARATOR(ACOV)
ACOvervoltagerisingthresholdon
VACOVOVPSETMeasuredonOVPSET3.0073.13.193V
(SeeOVPSETinTable1)
ACOvervoltagerisingdeglitch1.3
VACOV_HYSms
ACOvervoltagefallingdeglitch1.3
THERMALSHUTDOWNCOMPARATOR
TSHUTThermalshutdownrisingtemperatureTemperatureIncreasing155°C
TSHUT_HYSThermalshutdownhysteresis,falling20°C
BATTERYSWITCH(BATDRV)DRIVER
RDS(off)_BATBATFETTurn-offresistanceVACN>5V160Ω
RDS(on)_BATBATFETTurn-onresistanceVACN>5V3kΩ
V/BATDRV_REG=VACN–VBATDRVwhen
V/BATDRV_REGBATFETdrivevoltage6.5V
VACN>5VandBATFETison
DelaytoturnoffBATFETafteradapterisdetected
BATFETPower-updelay518700908ms
(afterVACDET>2.4V)
8SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
ELECTRICALCHARACTERISTICS(continued)
7V≤VPVCC≤24V,0°C<TJ<125°C,typicalvaluesareatTA=25°C,withrespecttoAGND(unlessotherwisenoted)
PARAMETERTESTCONDITIONSMINTYPMAXUNIT
ACSWITCH(ACDRV)DRIVER
RDS(off)_ACACFETturn-offresistanceVPVCC>5V80Ω
RDS(on)_ACACFETturn-onresistanceVPVCC>5V2.5kΩ
V/ACDRV_REG=VPVCC–VACDRVwhen
V/ACDRV_REGACFETdrivevoltage6.5V
VPVCC>5VandACFETison
DelaytoturnonACFETafteradapterisdetected
ACFETPower-upDelay518700908ms
(afterVACDET>2.4V)
AC/BATMOSFETDRIVERSTIMING
DeadtimewhenswitchingbetweenACDRVand
Driverdeadtime10µs
BATDRV
PWMHIGHSIDEDRIVER(HIDRV)
RDS(on)_HIHighsidedriverturn-onresistanceVBTST–VPH=5.5V,testedat100mA36Ω
RDS(off)_HIHighsidedriverturn-offresistanceVBTST–VPH=5.5V,testedat100mA0.71.4Ω
VBTST_REFRESHBootstraprefreshcomparatorthresholdVBTST–VPHwhenlowsiderefreshpulseis4V
voltagerequested
PWMLOWSIDEDRIVER(LODRV)
RDS(on)_LOLowsidedriverturn-onresistanceREGN=6V,testedat100mA36Ω
RDS(off)_LOLowsidedriverturn-offresistanceREGN=6V,testedat100mA0.61.2Ω
PWMDRIVERSTIMING
DriverDeadTime—Deadtimewhen
switchingbetweenLODRVandHIDRV.30ns
NoloadatLODRVandHIDRV
PWMOSCILLATOR
FSWPWMswitchingfrequency240300360kHz
VRAMP_HEIGHTPWMrampheightAspercentageofPVCC6.6%PVCC
QUIESCENTCURRENT
Totaloff-statequiescentcurrentintoVBAT=16.8V,VACDET<0.6V,
IOFF_STATEpinsSRP,SRN,BAT,BTST,PH,710µA
VPVCC>5V,TJ=0to85°C
PVCC,ACP,ACN
Totalquiescentcurrentintopins:SRP,
IBATQ_CDAdapterpresent,VACDET>2.4V,chargedisabled100200µA
SRN,BAT,BTST,PH
IACAdapterquiescentcurrentVPVCC=20V,chargedisabled11.5mA
INTERNALSOFTSTART(8stepstoregulationcurrent)
Softstartsteps8step
Softstartsteptime1.7ms
CHARGERSECTIONPOWER-UPSEQUENCING
Delayfromwhenadapterisdetectedtowhenthe
Charge-enabledelayafterpower-up518700908ms
chargerisallowedtoturnon
LOGICINPUTPINCHARACTERISTICS(CHGEN,LEARN)
VIN_LOInputlowthresholdvoltage0.8V
VIN_HIInputhighthresholdvoltage2.1
IBIASInputbiascurrentVCHGEN=0toVREGN
1µA
tCHGEN_DEGLITCHChargeenabledeglitchtimeACDET>2.4V,CHGENrising2ms
LOGICINPUTPINCHARACTERISTICS(CELLS)
VIN_LOInputlowthresholdvoltage,3cellsCELLSvoltagefallingedge0.5
CELLSvoltagerisingforMIN,
VIN_MIDInputmidthresholdvoltage,2cells0.81.8V
CELLSvoltagefallingforMAX
VIN_HIInputhighthresholdvoltage,4cellsCELLSvoltagerising2.5
Inputbiasfloatcurrentfor2-cell
IBIAS_FLOATVCHGEN=0toVREGN–11µA
selection
OPEN-DRAINLOGICOUTPUTPINCHARACTERISTICS(ACGOOD)
VOUT_LOOutputlowsaturationvoltageSinkCurrent=5mA0.5V
Delay,ACGOODfalling 518700908ms
Delay,ACGOODrising7911ms
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback9
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
TYPICALCHARACTERISTIC
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
TableofGraphs(1)
Figure
VREFLoadandLineRegulationvsLoadCurrentFigure3
REGNLoadandLineRegulationvsLoadCurrentFigure4
BATVoltagevsVADJ/VDACRatioFigure5
ChargeCurrentvsSRSET/VDACRatioFigure6
InputCurrentvsACSET/VDACRatioFigure7
BATVoltageRegulationAccuracyvsChargeCurrentFigure8
BATVoltageRegulationAccuracyFigure9
ChargeCurrentRegulationAccuracyFigure10
InputCurrentRegulation(DPM)AccuracyFigure11
VIADAPTInputCurrentSenseAmplifierAccuracyFigure12
InputRegulationCurrent(DPM),andChargeCurrentvsSystemCurrentFigure13
TransientSystemLoad(DPM)ResponseFigure14
ChargeCurrentRegulationvsBATVoltageFigure15
EfficiencyvsBatteryChargeCurrentFigure16
BatteryRemoval(fromConstantCurrentMode)Figure17
ACDRVandBATDRVStartup Figure18
REFandREGNStartupFigure19
SystemSelectoronAdapterInsertionwith390-µFSYS-to-PGNDSystemCapacitorFigure20
SystemSelectoronAdapterRemovalwith390-µFSYS-to-PGNDSystemCapacitorFigure21
SystemSelectorLEARNTurn-Onwith390-µFSYS-to-PGNDSystemCapacitorFigure22
SystemSelectorLEARNTurn-Offwith390-µFSYS-to-PGNDSystemCapacitorFigure23
SystemselectoronAdapterInsertionFigure24
SelectorGateDriveVoltages,700msdelayafterACDETFigure25
ChargeronAdapterRemovalFigure26
ChargeEnable/DisableandCurrentSoft-StartFigure27
NonsynchronoustoSynchronousTransitionFigure28
SynchronoustoNonsynchronousTransitionFigure29
Near100%DutyCycleBootstrapRechargePulseFigure30
BatteryShortedChargerResponse,OverCurrentProtection(OCP)andChargeCurrentRegulationFigure31
ContinuousConductionMode(CCM)SwitchingWaveformsFigure32
DiscontinuousConductionMode(DCM)SwitchingFigure33
Waveforms
(1)TestresultsbasedonFigure2applicationschematic.VIN=20V,VBAT=3-cellLi-Ion,ICHG=3A,IADAPTER_LIMIT=4A,TA=25°C,
unlessotherwisespecified.
10SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS “A v \ was .Lm Current . "m REGN V Load Cunem V mA SRSETIVDAC Rm ACSEYNDAC Ralio
-0.20
-0.10
0
0.10
0.20
0.30
0.40
0.50
0 10 20 30 40 50
VREF-LoadCurrent-mA
RegulationError-%
PVCC=10V
PVCC=20V
-3
-2.50
-2
-1.50
-1
-0.50
0
0 10 20 30 40 50 60 70 80
REGN-LoadCurrent-mA
RegulationError-%
PVCC=10V
PVCC=20V
0
1
2
3
4
5
6
7
8
9
10
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
SRSET/VDACRatio
ChargeCurrentRegulation- A
SRSET Varied,
4-Cell,
Vbat=16V
16
16.2
16.4
16.6
16.8
17
17.2
17.4
17.6
17.8
18
18.2
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
VADJ/VDACRatio
VoltageRegulation-V
VADJ=0-VDAC,
4-Cell,
NoLoad
V =16.8V
reg
-0.2
-0.1
0
0.1
0.2
02000 4000 6000 8000
ChargeCurrent-mA
RegulationError-%
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
VREFLOADANDLINEREGULATIONREGNLOADANDLINEREGULATION
vsvs
LoadCurrentLOADCURRENT
Figure3.Figure4.
BATVOLTAGECHARGECURRENT
vsvs
VADJ/VDACRATIOSRSET/VDACRATIO
Figure5.Figure6.
INPUTCURRENTBATVOLTAGEREGULATIONACCURACY
vsvs
ACSET/VDACRATIOCHARGECURRENT
Figure7.Figure8.
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback11
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS ‘ x x w , ‘ ‘ v ‘ :vmmf 777777777777 EELS” L——- L—g: ,4,” ‘ ,L,, 7 , ' /\_ _LE_ _s_ w : 7 7‘ 7 7 7x7 7 7 7 + 7 3% a; 77 77¢ Mi 77777L.» x x m ; V'—-—‘ ’71:?” y T’ > ' , ,,,,\,, 77L, 33—7 ‘.___,_r'—fl_.__ ‘ ‘ m , l 7 Tim; = 4 Ins/div
SRSET Varied
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
0 2 4 6 8
I Setpoint- A
(CHRG) -
RegulationError-%
4-Cell,VBAT =16V
VADJ=0-VDAC
-0.10
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.10
16.5 17 17.5 18 18.5 19
V -Setpoint-V
(BAT)
RegulationError-%
4-Cell,noload
ACSET Varied
-2
-1
0
1
2
3
4
5
6
7
8
9
10
0 1 2 3 4 5 6
InputCurrentRegulationSetpoint- A
RegulationError-%
4-Cell,VBAT =16V
Iadapt AmplifierGain
-25
-20
-15
-10
-5
0
5
0 1 2 3 4 5 6 7 8 9 10
I - A
(ACPWR)
PercentError
V =20V,CHG=EN
I
V =20V,CHG=DIS
I
V =20V,
4-Cell,
V =16V
I
bat
0
1
2
3
4
5
0 1 2 3 4
SystemCurrent- A
IchrgandIin- A
InputCurrent
ChargeCurrent
SystemCurrent
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
BATVOLTAGEREGULATIONACCURACYCHARGECURRENTREGULATIONACCURACY
Figure9.Figure10.
INPUTCURRENTREGULATION(DPM)ACCURACYVIADAPTINPUTCURRENTSENSEAMPLIFIERACCURACY
Figure11.Figure12.
INPUTREGULATIONCURRENT(DPM),ANDCHARGE
CURRENT
vs
SYSTEMCURRENTTRANSIENTSYSTEMLOAD(DPM)RESPONSE
Figure13.Figure14.
12SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS \ \ \ AT 7 F\ J ‘ ‘ ‘ L M w 2w 4:39 “W > ( , 3% V." \ . 5E "'4 L .- Time = 5 msldiv ' :5: b“ “N , '11: 312?: L“ l “2 ‘ 5’? ‘W TWW‘MVM “WW“ .2 V E! if” u> may ‘ "‘ —-4 7 '3 7 WW 23H»,,H4H>.HH, WW HH‘H‘HHWHH‘H‘H ”Z Wm ) W 7 / 4 2: vm \ Q> .., W , , (- Time = 2 Ins/div
V =20V,
Ichrg_set=4 A,
T =20°C
4Cell
in
A
0
1
2
3
4
5
0 2 4 6 8 10 12 14 16 18
BatteryVoltage-V
ChargeCurrent- A
70
80
90
100
02000 4000 6000 8000
BatteryChargeCurrent-mA
Efficiency-%
V =12.6V
reg
V =16.8V
(BAT)
V =8.4V
reg
Ch4
5V/div
Ch1
2 V/div
Ch2
20 V/div
Ch3
5 V/div
t − Time=100ms/div
VACGOOD
VACDRV
VBATDRV
VACDET
Ch2
20 V/div
t − Time=400 s/divm
Ch1
20 V/div
Ch4
10 V/div
Ch3
10 V/div
VBAT
VSYS
VACDRV
VBATDRV
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
CHARGECURRENTREGULATIONEFFICIENCY
vsvs
BATVOLTAGEBATTERYCHARGECURRENT
Figure15.Figure16.
BATTERYREMOVALACDRVANDBATDRVSTARTUP
Figure17.Figure18.
SYSTEMSELECTORONADAPTERINSERTIONWITH
REFANDREGNSTARTUP390µFSYS-TO-PGNDSYSTEMCAPACITOR
Figure19.Figure20.
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback13
ProductFolderLink(s):bq24751B
l TEXAS ch: ch: cm HIV/aw zov/aw znv/aw cm unwaw INSTRUMENTS ; m2; ‘ w m warm WW 3 ‘ 5‘ w: 22mm Wm» / s: , 7 ’ 6; vs“ ' ’ a 23 W iww ‘mmwrux‘» ugvm w Mum mm, “ x - Time = 400 us/div “HHM‘H W -———-————-——-
Ch2
20 V/div
t − Time=2ms/div
Ch1
20 V/div
Ch4
10 V/div
Ch3
10 V/div
VBAT
VSYS
VACDRV
VBATDRV
Ch2
20 V/div
t − Time=400ms/div
VACDRV
Ch1
20 V/div
Ch1
7.2 V
Ch4
5 A/div
VACPWR
VACGOOD
IL
Ch3
5 V/div
Ch3
5 A/div
t − Time=1ms/div
Ch1
5 V/div
Ch1
10.8 V
Ch2
5 V/div
VSYS
VACDRV
VACOP
IIN
Ch4
500 mV/div
Ch3
2 A/div
VBAT
t − Time=200 s/divm
VIN
IL
Ch1
5 V/div
Ch1
12.6 V
Ch4
5 V/div
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
SYSTEMSELECTORONADAPTERREMOVALWITHSYSTEMSELECTORLEARNTURN-ONWITH
390µFSYS-TO-PGNDSYSTEMCAPACITOR390µFSYS-TO-PGNDSYSTEMCAPACITOR
Figure21.Figure22.
SYSTEMSELECTORLEARNTURN-OFFWITH
390µFSYS-TO-PGNDSYSTEMCAPACITORSYSTEMSELECTORONADAPTERINSERTION
Figure23.Figure24.
SELECTORGATEDRIVEVOLTAGES,700MSDELAY
AFTERACDETCHARGERonADAPTERREMOVAL
Figure25.Figure26.
14SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS —"‘-———‘ -—-——‘ —'* :“E‘i‘ifihdfidfifid __-_/—— H- up-pLL-thpn ‘l“1”"“|“!”UJ_UL”J
Ch3
2 A/div
t − Time=4ms/div
Ch1
10 V/div
Ch4
1 V/div
VCHGEN
VPH
IBAT
Ch2
20 V/div
VBAT
Ch4
5 V/div
t − Time=4 s/divm
VHIDRV
VPH
VLDDRV
IL
Ch1
10 V/div
Ch2
10 V/div
Ch3
2 A/div
Ch4
2 A/div
t − Time=4ms/div
Ch1
20 V/div
Ch2
20 V/div
VPH
VLODRV
IL
Ch3
5 V/div
VHIDRV
Ch3
2 A/div
t − Time=2 s/divm
Ch2
10 V/div
VPH
VLODRV
IL
Ch4
5 V/div
Ch3
2 A/div
t − Time=400 s/divm
Ch4
10 V/div
VBAT
IL
Ch4
5 A/div
t − Time=1 s/divm
Ch1
20 V/div
Ch2
20 V/div
VPH
VLODRV
IL
Ch3
5 V/div
VHIDRV
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
CHARGEENABLE/DISABLEANDCURRENTSOFT-STARTNONSYNCHRONOUSTOSYNCHRONOUSTRANSITION
Figure27.Figure28.
SYNCHRONOUSTONONSYNCHRONOUSTRANSITIONNEAR100%DUTYCYCLEBOOTSTRAPRECHARGEPULSE
Figure29.Figure30.
BATTERYSHORTEDCHARGERRESPONSE,
OVERCURRENTPROTECTION(OCP)ANDCHARGECONTINUOUSCONDUCTIONMODE(CCM)SWITCHING
CURRENTREGULATIONWAVEFORMS
Figure31.Figure32.
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback15
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
Ch4
2 A/div
t − Time=1 s/divm
Ch1
20 V/div
Ch2
20 V/div
VPH
VLODRV
IL
Ch3
5 V/div
VHIDRV
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
DISCONTINUOUSCONDUCTIONMODE(DCM)SWITCHING
WAVEFORMS
Figure33.
16SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
mil 3: f 3Ker % 3 33333. 3 , 34 33 33, my i: Mi WE 33::
IADAPT
ACGOOD
PVCC
ACDRV
BATDRV
BTST
HIDRV
PH
REGN
LODRV
PGND
bq24751B
ACDET
CHGEN
ACP
ACN
BAT
CELLS
6V LDO
V(ACP-ACN)
+
-
ADAPTER DETECTED
COMP
ERROR
AMPLIFIER
V(ACN-BAT)
V(IADAPT)
+
-20x
ACP
ACN
ENA_BIAS
20 µA
IIN_ER
BAT_ER
ICH_ER
1V
20uA
285 mV
+
_
IIN_REG
VBAT_REG
IBAT_ REG
ACN-6V
PVCC-6V
PVCC
PVCC-6V PVCC-6V
LDO
DC-DC
CONVERTER
PWM LOGIC
PVCC
PH
4 V +
_
BTST REFRESH
CBTST
SYSTEM
POWER
SELECTOR
LOGIC
CHGEN
CHG_OCP
BAT_OVP
155 C°
IC Tj TSHUT
BAT
185 mV
+
_
PVCC
PVCC- BAT
LEVEL
SHIFTER
ACN
+
-
+
-
+
-
+
-
+
-
+
-
+
-
+
-
BAT_SHORT
ACOP
ACLOWV
SYNCH
V(SRP-SRN) CHG_OCP
+
-
145% X IBAT_REG
SYNCH
+
-
V(SRP - SRN)
SRSET
VADJ
VDAC
ACSET
VBAT_REG
IBAT_REG
IIN_REG
VBATSET
IBATSET
IINSET
RATIO
PROGRAM
+
-
13 mV
BAT BAT_OVP
+
-
104% X VBAT_REG
ACFET_ON
ACOP
ACOV
+
-
UVLO
+
-
+
-
3.1 V
PVCC
+
-
4 V
VREF 3.3 V
LDO PVCC
AGND
FBO
EAI EAO
VREFGOOD
ENA_BIAS
2.4 V
+
-
ENA_BIAS
0.6 V
+
-
5µA
VREF
Isrc=K*V(PVCC-ACP)
K=18 µA/V
ACOPDET
-
+
2 V -
+
ENA_SRC
ENA_SNK S
R Q
Q
ACDET
PVCC_UVLO
ACOP_LATCH
Delay
Rising
ACLOWV
+
-
+
-
ACP
3.0 V
UVLO
ACOV
V(ACN-BAT)
700 ms
OVPSET
LEARN
CHGEN
V(SRP-SRN)
+
–
BAT BAT_SHORT
+
–
2.9V/cell
+
–
20x
SRP
SRN
3.5mA
3.5mA
CHRG_ON
UVLO
VREFGOOD
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
FUNCTIONALBLOCKDIAGRAM
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback17
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS O10 VDAC SR
DETAILEDDESCRIPTION
BatteryVoltageRegulation
4 0.512
é ù
æ ö
= ´ + ´
ê ú
ç ÷
ê ú
è ø
ë û
VADJ
BATT
VDAC
V
V cell count V
V
(1)
BatteryCurrentRegulation
ICHARGE +VSRSET
VVDAC
0.10
RSR
(2)
InputAdapterCurrentRegulation
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
Thebq24751Busesahigh-accuracyvoltageregulatorforchargingvoltage.Internaldefaultbatteryvoltage
settingVBATT=4.2V×cellcount.TheregulationvoltageisratiometricwithrespecttoVADC.TheratioofVADJ
andVDACprovidesextra12.5%adjustrangeonVBATTregulationvoltage.Bylimitingtheadjustrangeto12.5%
oftheregulationvoltage,theexternalresistormismatcherrorisreducedfrom±1%to±0.1%.Therefore,an
overallvoltageaccuracyasgoodas0.5%ismaintained,whileusing1%mismatchedresistors.Ratiometric
conversionalsoallowscompatibilitywithD/Asormicrocontrollers(µC).Thebatteryvoltageisprogrammed
throughVADJandVDACusingEquation1.
TheinputvoltagerangeofVDACisbetween2.6Vand3.6V.VADJissetbetween0andVDAC.VBATTdefaults
to4.2V×cellcountwhenVADJisconnectedtoREGN.
TheCELLSpinisthelogicinputforselectingthecellcount.ConnectCELLStotheappropriatevoltagelevelto
charge2,3,or4Li+cells,asshowninTable2.Whenchargingothercellchemistries,useCELLStoselectan
outputvoltagerangeforthecharger.
Table2.Cell-CountSelection
CELLSCELLCOUNT
Float2
AGND3
VREF4
Theper-cellcharge-terminationvoltageisafunctionofthebatterychemistry.Consultthebatterymanufacturerto
determinethisvoltage.
TheBATpinisusedtosensethebatteryvoltageforvoltageregulationandshouldbeconnectedasclosetothe
batteryaspossible,ordirectlyontheoutputcapacitor.A0.1-µFceramiccapacitorfromBATtoAGNDis
recommendedtobeasclosetotheBATpinaspossibletodecouplehigh-frequencynoise.
TheSRSETinputsetsthemaximumchargecurrent.BatterycurrentissensedbyresistorRSRconnected
betweenSRPandSRN.Thefull-scaledifferentialvoltagebetweenSRPandSRNis100mV.Thus,fora
0.010-Ωsenseresistor,themaximumchargingcurrentis10A.SRSETisratiometricwithrespecttoVDACusing
Equation2:
TheinputvoltagerangeofSRSETisbetween0andVDAC,upto3.6V.
TheSRPandSRNpinsareusedtosenseacrossRSR,withadefaultvalueof10mΩ.However,resistorsofother
valuescanalsobeused.Alargersense-resistorvalueyieldsalargersensevoltage,andahigherregulation
accuracy.However,thisisattheexpenseofahigherconductionloss.
ThetotalinputcurrentfromanACadapterorotherDCsourcesisafunctionofthesystemsupplycurrentand
thebatterychargingcurrent.Systemcurrentnormallyfluctuatesasportionsofthesystemsarepoweredupor
down.WithoutDynamicPowerManagement(DPM),thesourcemustbeabletosupplythemaximumsystem
currentandthemaximumchargerinputcurrentsimultaneously.ByusingDPM,theinputcurrentregulator
reducesthechargingcurrentwhentheinputcurrentexceedstheinputcurrentlimitsetbyACSET.Thecurrent
capacityoftheACadaptercanbelowered,reducingsystemcost.
Similartosettingbattery-regulationcurrent,adaptercurrentissensedbyresistorRACconnectedbetweenACP
andACN.ItsmaximumvalueissetbyACSET,whichisratiometricwithrespecttoVDAC,usingEquation3.
18SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS VDAC AC is above 9 banerx
IADAPTER +VACSET
VVDAC
0.10
RAC
(3)
AdapterDetectandPowerUp
EnableandDisableCharging
SystemPowerSelector
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
TheinputvoltagerangeofACSETisbetween0andVDAC,upto3.6V.
TheACPandACNpinsareusedtosenseRACwithadefaultvalueof10mΩ.However,resistorsofothervalues
canalsobeused.Alargersense-resistorvalueyieldsalargersensevoltage,andahigherregulationaccuracy.
However,thisisattheexpenseofahigherconductionloss.
AnexternalresistorvoltagedividerattenuatestheadaptervoltagetotheACDETpin.Theadapterdetect
thresholdshouldtypicallybeprogrammedtoavaluegreaterthanthemaximumbatteryvoltageandlowerthan
theminimum-allowedadaptervoltage.TheACDETdividershouldbeplacedbeforetheACFETinordertosense
thetrueadapterinputvoltagewhethertheACFETisonoroff.Beforetheadapterisdetected,BATFETstayson
andACFETturnsoff.
IfPVCCisbelow4V,thedeviceisdisabled.IfACDETisbelow0.6VbutPVCCisabove4V,partofthebiasis
enabled,includingacrudebandgapreference,ACFETdriveandBATFETdrive.IADAPTisdisabledandpulled
downtoGND.Thetotalquiescentcurrentislessthan10µA.
WhenACDETrisesabove0.6VandPVCCisabove4V,allthebiascircuitsareenabledandVREFrisesto3.3
V,andtheREGNoutputrisesto6VwhenCHGENisLOW.IADAPTbecomesvalidtoproportionallyreflecttheadaptercurrent.
WhenACDETkeepsrisingandpasses2.4V,avalidACadapterispresent.700mslater,thefollowingoccurs:
•ACGOODispulledhighthroughtheexternalpull-upresistortothehostdigitalvoltagerail;
•ACFETisallowedtoturnonandBATFETturnsoffconsequently;(refertoSystemPowerSelector)
•Chargingbeginsifalltheconditionsaresatisfied.(refertoEnableandDisableCharging)
Thefollowingconditionsmustbevalidbeforethechargefunctionisenabled:
•CHGENisLOW
•PVCC>UVLO
•Adapterisdetected
•AdaptervoltageishigherthanBAT+185mV
•Adapterisnotovervoltage(ACOV)
•700msdelayiscompleteaftertheadapterisdetectedplus10msACOCtime
•ThermalShut(TSHUT)isnotvalid
•TSiswithinthetemperaturequalificationwindow
•VDAC>2.4V
•LEARNislow
Thebq24751Bautomaticallyswitchesbetweenconnectingtheadapterorbatterypowertothesystemload.By
default,thebatteryisconnectedtothesystemduringpoweruporwhenavalidadapterisnotpresent.Whenthe
adapterisdetected,thebatteryisfirstdisconnectedfromthesystem,thentheadapterisconnected.An
automaticbreak-before-makealgorithmpreventsshoot-throughcurrentswhentheselectortransistorsswitch.
TheACDRVsignaldrivesapairofback-to-backp-channelpowerMOSFETs(withsourcesconnectedtogether
andtoPVCC)connectedbetweentheadapterandACP.TheFETconnectedtotheadapterpreventsreverse
dischargefromthebatterytotheadapterwhenitisturnedoff.Thep-channelFETwiththedrainconnectedto
theadapterinputprovidesreversebatterydischargeprotectionwhenoff;andalsominimizessystempower
dissipation,withitslowRDS(on),comparedtoaSchottkydiode.Theotherp-channelFETconnectedtoACP
separatesthebatteryfromtheadapter,andprovidesbothACOCcurrentlimitandACOPpowerlimittothe
system.TheBATDRVsignalcontrolsap-channelpowerMOSFETplacedbetweenBATandthesystem.
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback19
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS not delecte efore ACF y from sh AT to sw ery. The b rge turns ARN is
BatteryLearnCycles
AutomaticInternalSoft-StartChargerCurrent
ConverterOperation
Theresonantfrequency,fo,isgivenby:
fo+1
2pLoCo
Ǹ
where(fromFigure1schematic)
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
Whentheadapterisnotdetected,theACDRVoutputispulledtoPVCCtoturnofftheACFET,disconnectingthe
adapterfromsystem.BATDRVstaysatACN–6Vtoconnectthebatterytosystem.
At700msafteradapterisdetected,thesystembeginstoswitchfromthebatterytotheadapter.TheACN
voltagemustbe285mVaboveBATtoenabletheswitching.Thebreak-before-makelogicturnsoffbothACFET
andBATFETfor10µsbeforeACFETturnson.Thisisolatesthebatteryfromshoot-throughcurrentoranylarge
dischargingcurrent.TheBATDRVoutputispulleduptoACNandtheACDRVpinissettoPVCC–6Vbyan
internalregulatortoturnonthep-channelACFET,connectingtheadaptertothesystem.
Whentheadapterisremoved,thesystemwaitstillACNdropsbacktowithin285mVaboveBATtoswitchfrom
theadapterbacktothebattery.Thebreak-before-makelogicensuresa10-µsdeadtime.TheACDRVoutputis
pulleduptoPVCCandtheBATDRVpinissettoACN–6Vbyaninternalregulatortoturnonthep-channel
BATFET,connectingthebatterytothesystem.
AsymmetricalgatedrivefortheACDRVandBATDRVdriversprovidesfastturn-offandslowturn-onofthe
ACFETandBATFETtohelpthebreak-before-makelogicandtoallowasoft-startatturn-onofeitherFET.The
soft-starttimecanbefurtherincreased,byputtingacapacitorfromgatetosourceofthep-channelpower
MOSFETs.
AbatteryLearncyclecanbeimplementedusingtheLEARNpin.AlogiclowonLEARNkeepsthesystempower
selectorlogicinitsdefaultstatesdependantontheadapter.Ifadapterisnotdetected,then;theACFETiskept
off,andtheBATFETiskepton.Iftheadapterisdetected,theBATFETiskeptoff,andtheACFETiskepton.
WhentheLEARNpinisatlogichigh,thesystempowerselectorlogicisoverridden,keepingtheACFEToffand
theBATFETonwhentheadapterispresent.Thisisusedtoallowthebatterytodischargeinordertocalibrate
thebatterygasgaugeoveracompletedischarge/chargecycle.ChargeturnsoffwhenLEARNishigh.The
controllerautomaticallyexitsthelearncyclewhenBAT<2.9Vpercell.BATDRVturnsoffandACDRVturnson.
Thechargerautomaticallysoft-startsthechargerregulationcurrenteverytimethechargerisenabledtoensure
thereisnoovershootorstressontheoutputcapacitorsorthepowerconverter.Thesoft-startconsistsof
stepping-upthechargeregulationcurrentinto8evenly-dividedstepsuptotheprogrammedchargecurrent.Each
steplastsapproximately1ms,foratypicalrisetimeof8ms.Noexternalcomponentsareneededforthis
function.
Thesynchronous-buckPWMconverterusesafixed-frequency(300kHz)voltagemodewithafeed-forward
controlscheme.AType-IIIcompensationnetworkallowstheuseofceramiccapacitorsattheoutputofthe
converter.Thecompensationinputstageisinternallyconnectedbetweenthefeedbackoutput(FBO)andthe
error-amplifierinput(EAI).Thefeedbackcompensationstageisconnectedbetweentheerroramplifierinput
(EAI)anderroramplifieroutput(EAO).TheLCoutputfilterisselectedforanominalresonantfrequencyof8
kHz–12.5kHz.
CO=C11+C12
LO=L1
AninternalsawtoothrampiscomparedtotheinternalEAOerror-controlsignaltovarythedutycycleofthe
converter.Therampheightisone-fifteenthoftheinputadaptervoltage,makingitalwaysdirectlyproportionalto
theinputadaptervoltage.Thiscancelsoutanyloop-gainvariationduetoachangeininputvoltage,and
simplifiestheloopcompensation.Therampisoffsetby200mVinordertoallowa0%dutycyclewhentheEAO
signalisbelowtheramp.TheEAOsignalisalsoallowedtoexceedthesawtoothrampsignalinordertooperate
witha100%duty-cyclePWMrequest.Internalgate-drivelogicallowsa99.98%duty-cyclewhileensuringthat
20SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
SynchronousandNon-SynchronousOperation
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
theN-channelupperdevicealwayshasenoughvoltagetostayfullyon.IftheBTST-to-PHvoltagefallsbelow4V
formorethan3cycles,thehigh-sideN-channelpowerMOSFETisturnedoffandthelow-sideN-channelpower
MOSFETisturnedontopullthePHnodedownandrechargetheBTSTcapacitor.Thenthehigh-sidedriver
returnsto100%duty-cycleoperationuntilthe(BTST-PH)voltageisdetectedfallinglowagainduetoleakage
currentdischargingtheBTSTcapacitorbelow4V,andtheresetpulseisreissued.
The300-kHzfixed-frequencyoscillatortightlycontrolstheswitchingfrequencyunderallconditionsofinput
voltage,batteryvoltage,chargecurrent,andtemperature.Thissimplifiesoutput-filterdesign,andkeepsitoutof
theaudiblenoiseregion.Thecharge-currentsenseresistorRSRshouldbedesignedwithatleasthalformoreof
thetotaloutputcapacitanceplacedbeforethesenseresistor,contactingbothsenseresistorandtheoutput
inductor;andtheotherhalf,orremainingcapacitanceplacedafterthesenseresistor.Theoutputcapacitance
shouldbedividedandplacedonbothsidesofthecharge-currentsenseresistor.Aratioof50:50percentgives
thebestperformance;butthenodeinwhichtheoutputinductorandsenseresistorconnectshouldhavea
minimumof50%ofthetotalcapacitance.Thiscapacitanceprovidessufficientfilteringtoremovetheswitching
noiseandgivebettercurrent-senseaccuracy.TheType-IIIcompensationprovidesphaseboostnearthe
cross-overfrequency,givingsufficientphasemargin.
Thechargeroperatesinnon-synchronousmodewhenthesensedchargecurrentisbelowtheISYNSETinternal
settingvalue.Otherwise,thechargeroperatesinsynchronousmode.
Duringsynchronousmode,thelow-sideN-channelpowerMOSFETisonwhenthehigh-sideN-channelpower
MOSFETisoff.Theinternalgate-drivelogicusesbreak-before-makeswitchingtopreventshoot-through
currents.Duringthe30-nsdeadtimewherebothFETsareoff,theback-diodeofthelow-sidepowerMOSFET
conductstheinductorcurrent.Havingthelow-sideFETturn-onkeepsthepowerdissipationlow,andallowssafe
chargingathighcurrents.Duringsynchronousmode,theinductorcurrentalwaysflows,andthedeviceoperates
inContinuousConductionMode(CCM),creatingafixedtwo-polesystem.
Duringnon-synchronousoperation,afterthehigh-siden-channelpowerMOSFETturnsoff,andafterthe
break-before-makedead-time,thelow-siden-channelpowerMOSFETturnsonforapproximately80ns,thenthe
low-sidepowerMOSFETturnsoffandstaysoffuntilthebeginningofthenextcycle,whenthehigh-sidepower
MOSFETisturnedonagain.The80-nslow-sideMOSFETon-timeisrequiredtoensurethatthebootstrap
capacitorisalwaysrechargedandabletokeepthehigh-sidepowerMOSFETonduringthenextcycle.Thisis
importantforbatterychargers,whereunlikeregulardc-dcconverters,thereisabatteryloadthatmaintainsa
voltageandcanbothsourceandsinkcurrent.The80-nslow-sidepulsepullsthePHnode(connectionbetween
highandlow-sideMOSFET)down,allowingthebootstrapcapacitortorechargeuptotheREGNLDOvalue.
Afterthe80ns,thelow-sideMOSFETiskeptofftopreventnegativeinductorcurrentfromflowing.Theinductor
currentisblockedbytheturned-offlow-sideMOSFET,andtheinductorcurrentbecomesdiscontinuous.This
modeiscalledDiscontinuousConductionMode(DCM).
DuringtheDCMmode,theloopresponseautomaticallychangesandhasasingle-polesystematwhichthepole
isproportionaltotheloadcurrent,becausetheconverterdoesnotsinkcurrent,andonlytheloadprovidesa
currentsink.Thismeansthatatlowcurrents,theloopresponseisslower,becausethereislesssinkingcurrent
availabletodischargetheoutputvoltage.Atlowcurrentsduringnon-synchronousoperation,theremaybea
smallamountofnegativeinductorcurrentduringthe80-nsrechargepulse.Thechargeshouldbelowenoughto
beabsorbedbytheinputcapacitance.
WheneverBTST–PH<4V,the80-nsrechargepulseoccursonLODRV,thehigh-sideMOSFETdoesnotturn
on,andthelow-sideMOSFETdoesnotturnon(only80-nsrechargepulse).
Inthebq24751B,VISYNSET=ISYN×RSRisinternallysetto13mVasthecharge-currentthresholdatwhichthe
chargerchangesfromnon-synchronousoperationtosynchronousoperation.Thelow-sidedriverturnsonforonly
80nstochargetheboostcapacitor.Thisisimportanttopreventnegativeinductorcurrent,whichmaycausea
boosteffectinwhichtheinputvoltageincreasesaspoweristransferredfromthebatterytotheinputcapacitors.
ThisboosteffectcanleadtoanovervoltageonthePVCCnodeandpotentiallydamagethesystem.Theinductor
ripplecurrentisgivenby
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback21
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS able 0V disconne ake Brute 9 this lat
( ) ( )
_
2££
- ´ ´ ´ - ´ ´
= =
RIPPLE_MAX
SYN RIPPLE MAX
BAT
IN BAT IN
IN s s
RIPPLE
III
and
V1 1
V V V 1 D D
V f f
IL L
(4)
HighAccuracyIADAPTUsingCurrentSenseAmplifier(CSA)
InputOvervoltageProtection(ACOV)
InputUndervoltageLockout(UVLO)
ACLowvoltage(ACLOWV)
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
where
VIN=adaptervoltage
VBAT=BATvoltage
fS=switchingfrequency
L=outputinductor
D=VBAT/VIN,duty-cycle
IRIPPLE_MAXhappenswhenthedutycycle(D)valueiscloseto0.5atgivenVIN,fS,andL.
TheISYNSETcomparator,orchargeundercurrentcomparator,comparesthevoltagebetweenSRP-SRNand
theinternalthreshold.Thethresholdissetto13mVonthefallingedgewithan8-mVhysteresisontherising
edgewitha10%variation.
Anindustry-standard,high-accuracycurrentsenseamplifier(CSA)isusedbythehostorsomediscretelogicto
monitortheinputcurrentthroughtheanalogvoltageoutputoftheIADAPTpin.TheCSAamplifiesthesensed
inputvoltageofACP–ACNby20xthroughtheIADAPTpin.TheIADAPToutputisavoltagesource20times
theinputdifferentialvoltage.WhenPVCCisabove5VandACDETisabove0.6V,IADAPTnolongerstaysat
ground,butbecomesactive.Iftheuserwantstolowerthevoltage,theycanusearesistordividerfromIOUTto
AGND,andstillachieveaccuracyovertemperatureastheresistorscanbematchedaccordingtotheirthermal
coefficients.
A200-pFcapacitorconnectedontheoutputisrecommendedfordecouplinghigh-frequencynoise.Anadditional
RCfilterisoptional,afterthe200-pFcapacitor,ifadditionalfilteringisdesired.Notethataddingfilteringalso
addsadditionalresponsedelay.
ACOVprovidesprotectiontopreventsystemdamageduetohighinputvoltage.Oncetheadaptervoltageis
abovetheprogrammableOVPSETvoltage(3.1V),chargeisdisabled,theadapterisdisconnectedfromthe
systembyturningoffACDRV,andthebatteryisconnectedtothesystembyturningonBATDRV.ACOVisnot
latched— normaloperationresumeswhentheOVPSETvoltagereturnsbelow3.1V.
Thesystemmusthave5VminimumofPVCCvoltageforproperoperation.ThisPVCCvoltagecancomefrom
eithertheinputadapterorthebattery,usingadiode-ORinput.WhenthePVCCvoltageisbelow5V,thebias
circuitsREGN,VREF,andthegatedrivebiastoACFETandBATFETstayinactive,evenwithACDETabove
0.6V.
ACLOWVclearsthebreak-before-makeprotectionlatchwhenACP<3VinadditontoUVLOclearingthislatch
whenPVCC<UVLO.ItensurestheBATDRVisoffwhenACP<3V,andthusthisfunctionallowstheACDRVto
turnontheACFETagainwhenACP<3VorPVCC<UVLO.
22SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
BatteryOvervoltageProtection
BatteryShorted(BatteryUndervoltage)Protection
ChargeOvercurrentProtection
ThermalShutdownProtection
AdapterDetectedStatusRegister(ACGOODPin)
InputOverpowerProtection(ACOP)
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
TheconverterstopsswitchingwhenBATvoltagegoesabove104%oftheregulationvoltage.Theconverterwill
notallowthehigh-sideFETtoturnonuntiltheBATvoltagegoesbelow102%oftheregulationvoltage.This
allowsone-cycleresponsetoanovervoltagecondition,suchaswhentheloadisremovedorthebatteryis
disconnected.A10-mAcurrentsinkfromBATtoPGNDisononlyduringcharge,andallowsdischargingthe
storedoutput-inductorenergyintotheoutputcapacitors.
Thebq24751BhasaBATSHORTcomparatormonitoringtheoutputbatteryvoltage(BAT).Ifthevoltagefalls
below2.9Vpercell(5.8Vfor2cells,8.7Vfor3cells,11.6Vfor4cells),abattery-shortstatusisdetected.
BelowtheBAT_SHORTthreshold,thechargerreducesthechargecurrentto1/8thoftheprogrammedcharging
current(0.1×SRSET/VDAC)/8=C/8downtozerovoltsonBATpin..Thislowercurrentisusedasapre-charge
currentforover-dischargedbatterypacks.AbovetheBAT_SHORTthreshold(plushysteresis,thechargecurrent
resumesattheprogrammedvalue(0.1×SRSET/VDAC).
TheBAT_SHORTcomparatoralsoservesasadepleted-batteryalarmduringaLEARNcycle.Iftheselectorisin
aLEARNcycle,andthebatteryvoltagefallsbellowtheBAT_SHORTthreshold,theselectordisconnectsthe
batteryfromthesystemandconnectstheadaptertothesysteminordertoprotectthebatterypack.Ifbattery
voltageincreases,andLEARNisstilllogichigh,thentheselectordisconnectstheadapterfromthesystemand
reconnectsthebatterytothesystem.
Thechargerhasasecondaryovercurrentprotectionfeature.Itmonitorsthechargecurrent,andpreventsthe
currentfromexceeding145%ofregulatedchargecurrent.Thehigh-sidegatedriveturnsoffwhenthe
overcurrentisdetected,andautomaticallyresumeswhenthecurrentfallsbelowtheovercurrentthreshold.
TheQFNpackagehaslowthermalimpedance,whichprovidesgoodthermalconductionfromthesilicontothe
ambient,tokeepjunctiontemperatureslow.Asanaddedlevelofprotection,thechargerconverterturnsoffand
self-protectswhenthejunctiontemperatureexceedstheTSHUTthresholdof155°C.Thechargerstaysoffuntil
thejunctiontemperaturefallsbelow135°C.
Onestatusoutputisavailable,anditrequiresanexternalpullupresistortopullthepintothesystemdigitalrail
forahighlevel.
ACGOODgoeslowwhenACDETisabove2.4Vandthe700-msdelaytimeisover.Itindicatesthattheadapter
voltageishighenoughfornormaloperation.
TheACOC/ACOPcircuitprovidesareliablelayerofsafetyprotectionthatcancomplementothersafety
measures.ACOC/ACOPhelpstoprotectfrominputcurrentsurgeduetovariousconditionsincluding:
•Adapterinsertionandsystemselectorconnectingadaptertosystemwheresystemcapacitorsneedtocharge
•Learnmodeexitwhenadapterisreconnectedtothesystem;systemloadovercurrentsurge
•Systemshortedtoground
•Batteryshortedtoground
•Phaseshortedtoground
•High-sideFETshortedfromdraintosource(SYSTEMshortedtoPH)
•BATFETshortedfromdraintosource(SYSTEMshortedtoBAT)
Severalexamplesofthecircuitprotectingfromthesefaultconditionsareshownbelow.
Fordesignsusingtheselectorfunctions,aninputovercurrent(ACOC)andinputoverpowerprotectionfunction
(ACOP)isprovided.ThethresholdissetbyanexternalcapacitorfromtheACOPpintoAGND.Aftertheadapter
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback23
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS ay before
TheACOCcurrentLimitthresholdisequalto
)ACPPVCC(VIVIPower LIM_ACOCsdd -×=×=
.
)ACPPVCC(V18mA/V
V2C
i
VC
tACOP
ACOP
ACOPACOP
-×
×
=
D×
=D
(5)
ConditionsforACOPLatchOff:
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
isdetected(ACDETpin>2.4V),thereisa700-msdelaybeforeACGOODisassertedlow,andQ3(BATFET)is
turned-off.ThenQ1/Q2(ACFET)areturnedonbytheACDRVpin.WhenQ1/Q2(ACFET)areturnedon,the
ACFETallowsoperationinlinear-regulationmodetolimitthemaximuminputcurrent,ACOC,toasafelevel.The
ACOCcurrentlimitis1.5timestheprogrammedDPMinputcurrentlimitsetbytheratioofSRSET/VDAC.The
maximumallowablecurrentlimitis100mVacrossACP–ACN(10Afora10-mΩsenseresistor).
Thefirst2msaftertheACDRVsignalbeginstoturnon,ACOCmaylimitthecurrent;butthecontrollerisnot
allowedtolatchoffinordertoallowareasonabletimeforthesystemvoltagetorise.
After2ms,ACOPisenabled.ACOPallowstheACFETtolatchoffbeforetheACFETcanbedamagedby
excessivethermaldissipation.ThecontrolleronlylatchesiftheACOPpinvoltageexceeds2Vwithrespectto
AGND.InACOP,acurrentsourcebeginstochargetheACOPcapacitorwhentheinputcurrentisbeinglimited
byACOC.Thiscurrentsourceisproportionaltothevoltageacrossthesource-drainoftheACFET(VPVCC-ACP)by
an18-µA/Vratio.Thisdependencyallowsfastercapacitorchargingifthevoltageislarger(morepower
dissipation).ItallowsthetimetobeprogrammedbytheACOPcapacitorselected.Ifthecontrollerisnotlimiting
current,afixed5-µAsinkcurrentintotheACOPpintodischargetheACOPcapacitor.Thischargeanddischarge
effectdependsonwhetherthereisacurrent-limitcondition,andhasamemoryeffectthataveragesthepower
overtime,protectingthesystemfrompotentiallyhazardousrepetitivefaults.WhenevertheACOPthresholdis
exceeded,thechargeisdisabledandtheadapterisdisconnectedfromthesystemtoprotecttheACFETandthe
wholesystem.IftheACFETislatchedoff,theBATFETisturnedontoconnectthebatterytothesystem.
ThecapacitorprovidesapredictabletimetolimitthepowerdissipationoftheACFET.Sincetheinputcurrentis
constantattheACOCcurrentlimit,thedesignercancalculatethepowerdissipationontheACFET.
Thetimeittakestochargeto2Vcanbecalculatedfrom
AnACOPfaultlatchoffcanonlybeclearedbybringingtheACDETpinvoltagebelow2.4V,thenabove2.4V
(i.e.removeadapterandreinsert),orbyreducingthePVCCvoltagebelowtheUVLOthresholdandraisingit.
702msafterACDET(adapterdetected),and
a.ACOPvoltage>2V.TheACOPpinchargestheceramiccapacitorwheninanACOCcurrent-limitcondition.
TheACOPpindischargesthecapacitorwhennotinACOCcurrent-limit.
b.ACOPprotectsfromasingle-pulseACOCconditiondependingondurationandsource-drainvoltageof
ACFET.LargervoltageacrossACFETcreatesmorepowerdissipationsolatch-offprotectionoccursfaster,
byincreasingthecurrentsourceoutofACOPpin.
c.Memoryeffect(capacitorcharginganddischarging)allowsprotectionfromrepetitiveACOCconditions,
dependingondurationandfrequency.(Figure35)
d.Inshortconditionswhenthesystemisshortedtoground(ACN<2.4V)aftertheinitial2-msACDET.
24SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
‘5; TEXAS INSTRUMENTS
700ms
2ms
ACOC, No Latch-off
ACOC, with ACOP Latch-off,
Latch-offtimeaccumulates
onlywhenincurrentlimit
regulation, ACOC. Thetime
beforelatch-offis
programmablewithCacop,
andisinverselyproportionalto
source-drainvoltageof
ACFET (power). Cacop
charge/dischargepertime
alsoprovidesmemoryfor
poweraveragingovertime.
700msdelayafter
ACDET, beforeallow
ACDRVtoturn-on
Inallcases, after 700ms
delay, haveinputover-
currentprotection,
ACOC, bylinearlylimiting
inputcurrent.
Thresholdisequaltothe
lowerofIdpm*1.5, or
10A.
8ms
AllowChargeto Turn-on
AfterLatch-Off, Latch
canonlyclearby:
1) bringing ACDET below
2.4V, thenabove 2. 4V; or
2) bringingPVCCbelow
UVLO, thenabove
UVLO.
Vin
ACDET
ACGOOD
BATDRV
ACDRV
Vsystem
InputCurrent
Vadapter
0V
Vadapter
Vbattery
AllowCharge
ChargeCurrent
Ilim = 1.5xIdpm
(100mVmax
Across ACP_ACN)
V(ACOP)
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
A.ACFEToverpowerprotection;initialcurrentlimitallowssafesoft-startwithoutsystemvoltagedroop.
Figure34.ACOCProtectionDuringAdapterInsertion
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback25
ProductFolderLink(s):bq24751B
‘5'; TEXAS INSTRUMENTS ________:L__-
ACOC_REG
V(PVCC-ACP)
Iacop_pin
2V
V(ACOP)
ON OFF
ACDRV_ON
LATCH-OFF
LATCH-OFF
Ilim = 1.5xIdpm Iin
LATCH-OFF
MemoryEffect
AveragesPower
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
Figure35.ACOCProtectionandACOPLatchOffwithMemoryEffectExample
26SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
5µA
REF=3.3V
Isrc=K*V(PVCC-ACP)
K=18 µA/V
ACOP
Cacop
ACOP Adaptor
OverPower
Comparator
ACOPDET
-
+
S
R Q
Q
ACDET
1µs
Deglitch
ACOPDETDG
2V
-
+
ACP
PVCC
ACDRV
ACN
ENA_SRC
ENA_SNK
+
-
+
-
+
-
IIN
Differential Amp
CSA
V(ACP-ACN)
VDS
Differential Amp
V(PVCC-ACP)
Regulation
Reference
Lowestof
1.5xIDPM_PRG
or
10A (100mV)
IDPM_PRG
(100mV_max)
ACOCREG =
REGULATING
ACOCERROR
AMPLIFIER &
DRIVER
IADAPT
IDPM
Ratio-
metric
Program
ACSET
Toclearlatchfault , usermustremove
adapterandreinsert, orPVCCbrought
belowthenaboveinputUVLOthreshold
PVCC_UVLO
Rising-edgeSet
& Resetinputs
Turn-off ACDRV
ACDET 700 ms
Delay
/ACDRV & /
BATDRV
break-
before-make
logic
ACDRV_ON
Q2 (ACFET)
SI4435
P P
ADAPTER+
ADAPTER-
C2 C3
Q1 (ACFET)
SI4435
0.47 µF
2.2 µF
C1
2 Ω
R10
0.1 µF
C8
0.1 µF
0.1 µF
RAC
0.010 Ω
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
Figure36.ACOC/ACOPCircuitFunctionalBlockDiagram
Table3.ComponentListforTypicalSystemCircuitofFigure1
PARTDESIGNATORQTYDESCRIPTION
Q1,Q2,Q33P-channelMOSFET,–30V,–6A,SO-8,Vishay-Siliconix,Si4435
Q4,Q52N-channelMOSFET,30V,12.5A,SO-8,Fairchild,FDS6680A
D11Diode,DualSchottky,30V,200mA,SOT23,Fairchild,BAT54C
RAC,RSR2SenseResistor,10mΩ,1%,1W,2010,Vishay-Dale,WSL2010R0100F
L11Inductor,8.2µH,8.5A,24.8mΩ,Vishay-Dale,IHLP5050CE-01
C11Capacitor,Ceramic,2.2µF,25V,20%,X5R,1206,Panasonic,ECJ-3YB1E225M
C6,C7,C11,C124Capacitor,Ceramic,10µF,35V,20%,X5R,1206,Panasonic,ECJ-3YB1E106M
C4,C102Capacitor,Ceramic,1µF,25V,10%,X7R,2012,TDK,C2012X7R1E105K
C2,C3,C8,C9,C13,C14,C157Capacitor,Ceramic,0.1µF,50V,10%,X7R,0805,Kemet,C0805C104K5RACTU
C51Capacitor,Ceramic,100pF,25V,10%,X7R,0805,Kemet
C161Capacitor,Ceramic,0.47µF,25V,10%,X7R,0805,Kemet
R11Resistor,Chip,432kΩ,1/16W,1%,0402
R21Resistor,Chip,66.5kΩ,1/16W,1%,0402
R31Resistor,Chip,422kΩ,1/16W,1%,0402
R41Resistor,Chip,71kΩ,1/16W,5%,0402
R101Resistor,Chip,2Ω,1W,5%,2010
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback27
ProductFolderLink(s):bq24751B
‘5; TEXAS INSTRUMENTS
APPLICATIONINFORMATION
InputCapacitanceCalculation
Ci
Ri Li
Vi
VIN
IIN
Rc
Vc
Ci
Ri Li
Vi
VIN
IIN
Rc
Vc
Ri
2Lit
VIN(t) +IIN(t) RC)VCi(t) +VieƪRi*RC
wLisinwt)cos wtƫ
(6)
2
R V
1 2L
tii
R = R + R = - I (t) = sin
ti IN
CL C 2L L
i i i i
Rit
e tw w
w
æ ö
ç ÷
è ø
2Li
V (t) = V - V s in t + cos t
i i
Ci 2 Li
RttRt
ew w
w
æ ö
ç ÷
è ø
(7)
Ri)Rcu2Li
Ci
Ǹ
(8)
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
Duringtheadapterhotplug-in,theACDRVhasnotbeenenabled.TheACswitchisoffandthesimplified
equivalentcircuitoftheinputisshowninFigure37.
Figure37.SimplifiedEquivalentCircuitDuringAdapterInsertion
ThevoltageonthechargerinputsideVINisgivenby:
inwhich,
Thedampingconditionsis:
28SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
5
10
15
20
25
30
35
InputCapacitor Voltage-V
Time-ms
R =0.15
iWL =9.3
C =40 F
i
i
mH
m
(a)V withvariousC values
c i
(b)V withvariousL values
c i
(c)V withvariousR values
c i
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
5
10
15
20
25
30
35
InputCapacitor Voltage-V
Time-ms
C =20 F
im
C =40 F
im
R =0.21
L =9.3 H
i
i
W
m
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
5
10
15
20
25
30
35
InputCapacitor Voltage-V
Time-ms
L =5 H
im
L =12 H
im
R =0.15
C =40 F
i
i
W
m
R =0.5
iW
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
Figure38(a)demonstratesahigherCihelpsdampenthevoltagespike.Figure38(b)demonstratestheeffectof
theinputstrayinductanceLiupontheinputvoltagespike.Figure38(c)showshowincreasedresistancehelpsto
suppresstheinputvoltagespike.
Figure38.ParametricStudyOfTheInputVoltage
AsshowninFigure38,minimizingtheinputstrayinductance,increasingtheinputcapacitance,andadding
resistance(includingusinghigherESRcapacitors)helpssuppresstheinputvoltagespike.However,auseroften
cannotcontrolinputstrayinductanceandincreasingcapacitancecanincreasecosts.Therefore,themost
efficientandcost-effectiveapproachistoaddanexternalresistor.
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback29
ProductFolderLink(s):bq24751B
l TEXAS INSTRUMENTS VIN 5VIdiv m 4 m 4x 2m» IIN ZA/dlv ' ‘ ‘ MM {mus 'A ME 1 haw :7 V m :Mv mm ”mm Icu 2am mm an). m u 23
Rext
C1 C2
2.2 F
(25V,1210)
m
VIN VPVCC
0.1 F
(50V,0805,very
closetoPVCC)
m2
(0.5W,
1210anti-surge)
W
bq24751B
SLUS835A–JULY2008–REVISEDMARCH2009..........................................................................................................................................................
www.ti.com
Figure39depictstherecommendedinputfilterdesign.Themeasuredinputvoltageandcurrentwaveformsare
showninFigure40.Theinputvoltagespikehasbeenwelldampedbyaddinga2Ωresistor,whilekeepingthe
capacitancelow.
Figure39.RecommendedInputFilterDesignFigure40.AdapterDCSideHotPlug-inTestWaveforms
30SubmitDocumentationFeedbackCopyright©2008–2009,TexasInstrumentsIncorporated
ProductFolderLink(s):bq24751B
PCBLayoutDesignGuideline
(a)TopLayer
(b)BottomLayer
bq24751B
www.ti.com
..........................................................................................................................................................SLUS835A–JULY2008–REVISEDMARCH2009
1.ItiscriticalthattheexposedpowerpadonthebacksideoftheICpackagebesolderedtothePCBground.
EnsurethattherearesufficientthermalviasdirectlyundertheIC,connectingtothegroundplaneonthe
otherlayers.
2.Thecontrolstageandthepowerstageshouldberoutedseparately.Ateachlayer,thesignalgroundandthe
powergroundareconnectedonlyatthepowerpad.
3.TheACcurrent-senseresistormustbeconnectedtoACP(pin3)andACN(pin2)withaKelvincontact.The
areaofthisloopmustbeminimized.Anadditional0.1µFdecouplingcapacitorforACNisrequiredtofutther
reducenoise.ThedecouplingcapacitorsforthesepinsshouldbeplacedasclosetotheICaspossible.
4.Thecharge-currentsenseresistormustbeconnectedtoSRP(pin19),SRN(pin18)withaKelvincontact.
Theareaofthisloopmustbeminimized.Anadditional0.1µFdecouplingcapacitorforSRNisrequiredto
futtherreducenoise.ThedecouplingcapacitorsforthesepinsshouldbeplacedasclosetotheICas
possible.
5.DecouplingcapacitorsforPVCC(pin28),VREF(pin10),REGN(pin24)shouldbeplacedunderneaththeIC
(onthebottomlayer)withtheinterconnectionstotheICasshortaspossible.
6.DecouplingcapacitorsforBAT(pin17),IADAPT(pin15)mustbeplacedclosetothecorrespondingICpins
withtheinterconnectionstotheICasshortaspossible.
7.DecouplingcapacitorCXforthechargerinputmustbeplacedclosetotheQ4drainandQ5source.
Figure41showstherecommendedcomponentplacementwithtraceandvialocations.
FortheQFNinformation,pleaserefertothefollowinglinks:SCBA017andSLUA271
Figure41.LayoutExample
Copyright©2008–2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback31
ProductFolderLink(s):bq24751B
I TEXAS INSTRUMENTS Samples Samples Samples
PACKAGE OPTION ADDENDUM
www.ti.com 10-Dec-2020
Addendum-Page 1
PACKAGING INFORMATION
Orderable Device Status
(1)
Package Type Package
Drawing Pins Package
Qty Eco Plan
(2)
Lead finish/
Ball material
(6)
MSL Peak Temp
(3)
Op Temp (°C) Device Marking
(4/5)
Samples
BQ24751BRHDR ACTIVE VQFN RHD 28 3000 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 125 BQ
24751B
BQ24751BRHDT ACTIVE VQFN RHD 28 250 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 125 BQ
24751B
BQ24751BRHDTG4 ACTIVE VQFN RHD 28 250 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 125 BQ
24751B
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based
flame retardants must also meet the <=1000ppm threshold requirement.
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6) Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two
lines if the finish value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
I TEXAS INSTRUMENTS
PACKAGE OPTION ADDENDUM
www.ti.com 10-Dec-2020
Addendum-Page 2
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device Package
Type Package
Drawing Pins SPQ Reel
Diameter
(mm)
Reel
Width
W1 (mm)
A0
(mm) B0
(mm) K0
(mm) P1
(mm) W
(mm) Pin1
Quadrant
BQ24751BRHDR VQFN RHD 28 3000 330.0 12.4 5.3 5.3 1.5 8.0 12.0 Q2
BQ24751BRHDT VQFN RHD 28 250 180.0 12.4 5.3 5.3 1.5 8.0 12.0 Q2
PACKAGE MATERIALS INFORMATION
www.ti.com 14-Jul-2012
Pack Materials-Page 1
I TEXAS INSTRUMENTS TAPE AND REEL BOX DIMENSIONS
*All dimensions are nominal
Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
BQ24751BRHDR VQFN RHD 28 3000 367.0 367.0 35.0
BQ24751BRHDT VQFN RHD 28 250 210.0 185.0 35.0
PACKAGE MATERIALS INFORMATION
www.ti.com 14-Jul-2012
Pack Materials-Page 2
GENERIC PACKAGE VIEW RHD 28 VQFN - 1 mm max heigm 5 x 5 mm 0 5 mm pitch PLASTIC QUAD FLATPACKr N0 LEAD , . Images above are jusl a represenlalion of the package family, aclual package may vary Refel lo the product dala sheel for package details. 4204400/G I TEXAS INSTRI IMFNTS
T i Q rim—1 i E i W D? uuwuwu a 3 i Z LE; 1 C4 w mmmm El
www.ti.com
PACKAGE OUTLINE
5.15
4.85
5.15
4.85
1.0
0.8
0.05
0.00
2X 3
24X 0.5
2X 3
28X 0.65
0.45
28X 0.30
0.18
3.15 0.1
3.15 0.1
(0.2) TYP
VQFN - 1 mm max heightRHD0028B
PLASTIC QUAD FLATPACK - NO LEAD
4226146/A 08/2020
0.08 C
0.1 C A B
0.05
NOTES:
1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing
per ASME Y14.5M.
2. This drawing is subject to change without notice.
3. The package thermal pad must be soldered to the printed circuit board for thermal and mechanical performance.
PIN 1 INDEX AREA
SEATING PLANE
PIN 1 ID
SYMM
EXPOSED
THERMAL PAD
SYMM
1
7
814
15
21
22
28
29
SCALE 2.500
A
B
C
mfififiw TCg w ”w , E a E T E EIT ¢¢wtm+me % fl /% 5 71 a flU mfiifim/ EL
www.ti.com
EXAMPLE BOARD LAYOUT
24X (0.5)
(1.325)
(1.325)
(R0.05) TYP
0.07 MAX
ALL AROUND
0.07 MIN
ALL AROUND
28X (0.75)
28X (0.24)
(4.65)
(4.65)
( 3.15)
( 0.2) TYP
VIA
VQFN - 1 mm max heightRHD0028B
PLASTIC QUAD FLATPACK - NO LEAD
4226146/A 08/2020
NOTES: (continued)
4. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature
number SLUA271 (www.ti.com/lit/slua271).
5. Vias are optional depending on application, refer to device data sheet. If any vias are implemented, refer to their locations shown
on this view. It is recommended that vias under paste be filled, plugged or tented.
SYMM
SYMM
LAND PATTERN EXAMPLE
EXPOSED METAL SHOWN
SCALE: 18X
SEE SOLDER MASK
DETAIL
1
7
814
15
21
22
28
29
METAL EDGE
SOLDER MASK
OPENING
EXPOSED METAL
METAL UNDER
SOLDER MASK
SOLDER MASK
OPENING
EXPOSED
METAL
NON SOLDER MASK
DEFINED
(PREFERRED)
SOLDER MASK DEFINED
SOLDER MASK DETAILS
mfim
www.ti.com
EXAMPLE STENCIL DESIGN
28X (0.75)
28X (0.24)
24X (0.5)
(4.65)
(4.65)
(0.785) TYP
(0.785) TYP
4X (1.37)
4X (1.37)
(R0.05) TYP
VQFN - 1 mm max heightRHD0028B
PLASTIC QUAD FLATPACK - NO LEAD
4226146/A 08/2020
NOTES: (continued)
6. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate
design recommendations.
SOLDER PASTE EXAMPLE
BASED ON 0.125 MM THICK STENCIL
SCALE: 20X
EXPOSED PAD 29
76% PRINTED SOLDER COVERAGE BY AREA UNDER PACKAGE
SYMM
SYMM
1
7
814
15
21
22
28
29
IMPORTANT NOTICE AND DISCLAIMER
TI PROVIDES TECHNICAL AND RELIABILITY DATA (INCLUDING DATASHEETS), DESIGN RESOURCES (INCLUDING REFERENCE
DESIGNS), APPLICATION OR OTHER DESIGN ADVICE, WEB TOOLS, SAFETY INFORMATION, AND OTHER RESOURCES “AS IS”
AND WITH ALL FAULTS, AND DISCLAIMS ALL WARRANTIES, EXPRESS AND IMPLIED, INCLUDING WITHOUT LIMITATION ANY
IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD
PARTY INTELLECTUAL PROPERTY RIGHTS.
These resources are intended for skilled developers designing with TI products. You are solely responsible for (1) selecting the appropriate
TI products for your application, (2) designing, validating and testing your application, and (3) ensuring your application meets applicable
standards, and any other safety, security, or other requirements. These resources are subject to change without notice. TI grants you
permission to use these resources only for development of an application that uses the TI products described in the resource. Other
reproduction and display of these resources is prohibited. No license is granted to any other TI intellectual property right or to any third
party intellectual property right. TI disclaims responsibility for, and you will fully indemnify TI and its representatives against, any claims,
damages, costs, losses, and liabilities arising out of your use of these resources.
TI’s products are provided subject to TI’s Terms of Sale (www.ti.com/legal/termsofsale.html) or other applicable terms available either on
ti.com or provided in conjunction with such TI products. TI’s provision of these resources does not expand or otherwise alter TI’s applicable
warranties or warranty disclaimers for TI products.
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2020, Texas Instruments Incorporated