Texas Instruments bq24704 Schematics

ACP

PVCC

ACDET

ACSET

DPMDET

CELLS

SRP

SRN

BAT

CHGEN

ACN

SRSET

1

24

2

3

18

5

6

4

17

16

15

14

13

23 22 21 20

7 8 9 10 11 12

19

AGND

VREF

VADJ

ACGOOD

ISYNSET

IADAPT

BTST

HIDR

V

PH

REGN

LODR

V

PGND

bq24704
QFN-24
TOP VIEW

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Not Recommended for New Designs

........................................................................................................................................................................................................SLUS838–MAY2009

LowCost,Host-ControlledLi-IonandLi-PolymerBatteryChargerWithLowIq

1

FEATURESAPPLICATIONS

2

•NMOS-NMOSSynchronousBuckConverter

with300kHzFrequencyand>95%Efficiency

•30-nsMinimumDriverDead-timeand99.5%

MaximumEffectiveDutyCycle

•High-AccuracyVoltageandCurrentRegulation

–±0.5%ChargeVoltageAccuracy
–±3%ChargeCurrentAccuracy
–±3%AdapterCurrentAccuracy
–±2%InputCurrentSenseAmpAccuracy

•Integration

–InternalLoopCompensation
–InternalSoft-Start

•Safety

–DynamicPowerManagement(DPM)with

StatusIndicator
–ChargerOvercurrentProtection
–BatteryOvervoltageProtection
–ThermalShutdown

•SupportsTwo,Three,orFourLi+CellsPACKAGEANDPIN-OUT

•8–24VAC/DC-AdapterOperatingRange

•AnalogInputswithRatiometricProgramming

viaResistorsorDAC/GPIOHostControl
–ChargeVoltage(4-4.512V/cell)
–ChargeCurrent(upto8A,with10-mΩ

SenseResistor)
–AdapterCurrentLimit(DPM)

•StatusandMonitoringOutputs

–AC/DCAdapterPresentwithProgrammable

VoltageThreshold
–DPMLoopActive(DPMDET)
–CurrentDrawnfromInputSource

•ChargeEnable

•24-pin,4x4-mmQFNPackage

•EnergyStarLowIq

–<10µAOff-stateDischargeCurrent
–<1.5mAOff-stateInputQuiescentCurrent

Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsofTexas
Instrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet.

1

2PowerPadisatrademarkofTexasInstruments.

PRODUCTIONDATAinformationiscurrentasofpublicationdate.
ProductsconformtospecificationsperthetermsoftheTexas
Instrumentsstandardwarranty.Productionprocessingdoesnot
necessarilyincludetestingofallparameters.

bq24704

•NotebookandNetbookComputers

•PortableData-CaptureTerminals

•PortablePrinters

•MedicalDiagnosticsEquipment

•BatteryBayChargers

•BatteryBack-UpSystems

DESCRIPTION

Thebq24704isahigh-efficiency,synchronous
batterychargerwithintegratedcompensationoffering
lowcomponentcountforspace-limitedLi-Ionand
Li-Polymerbatterychargingapplications.Charge
currentandvoltageprogrammingallowshigh
regulationaccuracies,andcanbeeitherhardwired
withresistors,orprogrammedbythesystem
power-managementmicrocontrollerusingaDACor
GPIOs.

Thebq24704chargestwo,three,orfourseriesLi+
cells,supportingupto8Aofchargecurrent,andis
availableina24-pin,4x4-mmthinQFNpackage.

Copyright©2009,TexasInstrumentsIncorporated

VREF

R

AC

0.01 Ω

Q1 (ACFET)

SI4435

Q3(BATFET)

SI4435

Controlled by

HOST

N

PP

ACN

ACP

ACDET

ACGOOD

SRSET

ACSET

VREF

GPIO

CELLS

CHGEN

VADJ

ADC IADAPT

HOST

PVCC

HIDRV

N

PH

BTST

REGN

LODRV

PGND

SRP

SRN

P

PACK+

PACK–

SYSTEM

ADAPTER +

ADAPTER–

ACGOOD

AGND

bq24704

432 kΩ
1%

66.5 kΩ
1%

R1

R2

C4

C2

C5

C8

Q4
FDS6680A

C9

D1 BAT54

C10

BAT

ISYNSET

R6
20 kΩ

DPMDET

R4

Q2 (ACFET)

SI4435

Controlled by

HOST

C6

C15

0.1 µF

C1

2 Ω

R10

2.2 µF

0.1 µF

1 µF

10 kΩ

100 pF

C14

0.1 µF

0.1 µF

1 µF

R

SR

0.01 Ω

0.1 µF

10 µF

C7

10 µF

C12
10 µF

PowerPad

D2

BAT54

DAC

Q5
FDS6680A

L1

8.2 µH

C3

0.1µF

R3

10kΩ

C13

0.1 µF

C11

10 µF

R15

10 kΩ

bq24704

Not Recommended for New Designs

SLUS838–MAY2009........................................................................................................................................................................................................

Thesedeviceshavelimitedbuilt-inESDprotection.Theleadsshouldbeshortedtogetherorthedeviceplacedinconductivefoam
duringstorageorhandlingtopreventelectrostaticdamagetotheMOSgates.

DESCRIPTION(CONTINUED)

Thebq24704featuresDynamicPowerManagement(DPM)andinputpowerlimiting.Thesefeaturesreduce
batterychargecurrentwhentheinputpowerlimitisreachedtoavoidoverloadingtheACadapterwhensupplying
theloadandthebatterychargersimultaneously.Ahighly-accuratecurrent-senseamplifierenablesprecise
measurementofinputcurrentfromtheACadaptertomonitortheoverallsystempower.

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(1)Pull-uprailcouldbeeitherVREForothersystemrail.
(2)SRSET/ACSETcouldcomefromeitherDACorresistordividers.
(3)VIN=20V,V

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Figure1.TypicalSystemSchematic,VoltageandCurrentProgrammedbyDAC

=3-cellLi-Ion,I

BAT

CHARGE

=3A,I

ADAPTER_LIMIT

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=4A

VREF

100 kΩ

R11

47 kΩ

R12

100 kΩ

R13

42 kΩ

R14

VREF

R

AC

0.01 Ω

Q1 (ACFET)

SI4435

Q3(BATFET)

SI4435

Controlled by

HOST

N

PP

ACN

ACP

ACDET

ACGOOD

SRSET

ACSET

VREF

GPIO

CELLS

CHGEN

VADJ

ADC

IADAPT

HOST

PVCC

HIDRV

N

PH

BTST

REGN

LODRV

PGND

SRP

SRN

P

PACK+

PACK–

SYSTEM

ADAPTER +

ADAPTER–

ACGOOD

AGND

bq24704

432 kΩ
1%

66.5 kΩ
1%

R1

R2

R3

C4

C2

C5

C8

Q4
FDS6680A

C9

D1 BAT54

C10

BAT

ISYNSET

R6
20 kΩ

DPMDET

R4

Q2 (ACFET)

SI4435

Controlled by

HOST

C6

C15

0.1 µF

C1

2 Ω

R10

2.2 µF

0.1 µF

1 µF

10 kΩ

10kΩ

100 pF

C14

0.1 µF

0.1 µF

1 µF

R

SR

0.01 Ω

0.1 µF

10 µF

C7
10 µF

C12
10 µF

PowerPad

REGN

D2

BAT54

Q5
FDS6680A

L1

8.2 µH

C3

0.1µF

C13

0.1 µF

C11

10 µF

R15

10 kΩ

bq24704

Not Recommended for New Designs

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........................................................................................................................................................................................................SLUS838–MAY2009

(1)Pull-uprailcouldbeeitherVREForothersystemrail.
(2)SRSET/ACSETcouldcomefromeitherDACorresistordividers.
(3)VIN=20V,V

=3-cellLi-Ion,I

BAT

Figure2.TypicalSystemSchematic,VoltageandCurrentProgrammedbyResistor

PACKAGETHERMALDATA

PartNumberPackageQuantity

bq2470424-PIN4x4mmQFN

PACKAGEθ

QFN–RGE

(1)Forthemostcurrentpackageandorderinginformation,seethePackageOptionAddendumattheendofthisdocument,orseetheTI

Websiteatwww.ti.com.

(2)ThisdataisbasedonusingtheJEDECHigh-KboardandtheexposeddiepadisconnectedtoaCupadontheboard.Thisis

connectedtothegroundplanebya2x3viamatrix.

Copyright©2009,TexasInstrumentsIncorporatedSubmitDocumentationFeedback3

(1)(2)

=3A,I

CHARGE

ADAPTER_LIMIT

ORDERINGINFORMATION

JA

45°C/W2.33W0.023W/°C

ProductFolderLink(s):bq24704

=4A

OrderingNumber

(TapeandReel)

bq24704RGER3000
bq24704RGET250

TA=25°CPOWERRATINGDERATINGFACTORABOVE

TA=25°C

bq24704

Not Recommended for New Designs

SLUS838–MAY2009........................................................................................................................................................................................................

Table1.TERMINALFUNCTIONS–24-PINQFN

TERMINAL

NAMENO.

PVCC1ICpowerpositivesupply.Placea0.1-µFceramiccapacitorfromPVCCtoPGNDpinclosetotheIC.

CHGEN 2

ACN3ACN2differential-modefiltering.Anoptional0.1-µFceramiccapacitorisplacedfromACNpintoAGNDfor

ACP4

ACDET5adapterinputtoACDETpintoAGNDpin.AdaptervoltageisdetectedifACDET-pinvoltageisgreaterthan2.4V.

ACSET6regulationset-pointduringDynamicPowerManagement(DPM).ProgrambyconnectingaresistordividerfromVREF

AGND7

VREF8

VADJ9regulationset-point.ProgrambyconnectingaresistordividerfromVREFtoVADJ,toAGND;or,byconnectingthe

ACGOOD10

ISYNSET11thresholdtoforcenon-synchronousconverteroperationatlowoutputcurrent,andtopreventnegativeinductor

IADAPT12

SRSET13regulationset-point.ProgrambyconnectingaresistordividerfromVREFtoSRSETtoAGND;orbyconnectingthe

BAT14BATpintoaccuratelysensethebatterypackvoltage.Placea0.1-µFcapacitorfromBATtoAGNDclosetotheICto

SRN15differential-modefiltering.Anoptional0.1-µFceramiccapacitorisplacedfromSRNpintoAGNDforcommon-mode

SRP16

CELLS172,3or4cellsselectionlogicinput.Logiclowprograms3cell.Logichighprograms4cell.Floatingprograms2cell.

DPMDET18currentisbeinglimitedbyreducingthechargecurrent.Connect10-kΩpullupresistorfromDPMDETtoVREFora

PGND19oflow-sidepowerMOSFET,togroundconnectionofinputandoutputcapacitorsofthecharger.Onlyconnectto

LODRV20PWMlowsidedriveroutput.Connecttothegateofthelow-sidepowerMOSFETwithashorttrace.

REGN21

PH22MOSFETdrain,high-sidepowerMOSFETsource,andoutputinductor).Connectthe0.1-µFbootstrapcapacitorfrom

HIDRV23PWMhighsidedriveroutput.Connecttothegateofthehigh-sidepowerMOSFETwithashorttrace.

BTST24

DESCRIPTION

Chargeenableactive-lowlogicinput.LOenablescharge.HIdisablescharge.Connecta10-kΩpull-upresistorfrom
CHGENtoapull-upsupplyrail.

Adaptercurrentsenseresistor,negativeinput.A0.1-µFceramiccapacitorisplacedfromACNtoACPtoprovide

common-modefiltering.
Adaptercurrentsenseresistor,positiveinput.A0.1-µFceramiccapacitorisplacedfromACNtoACPtoprovide

differential-modefiltering.A0.1-µFceramiccapacitorisplacedfromACPpintoAGNDforcommon-modefiltering.
Adapterdetectedvoltagesetinput.Programtheadapterdetectthresholdbyconnectingaresistordividerfrom

TheI
Adaptercurrentsetinput.ThevoltageratioofACSETvoltageversusVREFvoltageprogramstheinputcurrent

toACSETtoAGND;orbyconnectingtheoutputofanexternalDACtotheACSETpin.
Analogground.Groundconnectionforlow-currentsensitiveanaloganddigitalsignals.OnPCBlayout,connecttothe

analoggroundplane,andonlyconnecttoPGNDthroughthePowerPadunderneaththeIC.

3.3-Vregulatedvoltageoutput.Placea1-µFceramiccapacitorfromVREFtoAGNDpinclosetotheIC.Thisvoltage
couldbeusedforratiometricprogrammingofvoltageandcurrentregulation.

Chargevoltagesetinput.ThevoltageratioofVADJvoltageversusVREFvoltageprogramsthebatteryvoltage

outputofanexternalDACtoVADJ.VADJconnectedtoREGNprogramsthedefaultof4.2Vpercell.
Validadapteractive-lowdetectlogicopen-drainoutput.PulledlowwheninputvoltageisaboveACDETprogrammed

threshold.Connecta10-kΩpullupresistorfromACGOODpintopullupsupplyrail.
Synchronousmodecurrentsetinput.PlacearesistorfromISYNSETtoAGNDtoprogramthechargeundercurrent

current.Thresholdshouldbesetatgreaterthanhalfofthemaximuminductorripplecurrent(50%dutycycle).
Adaptercurrentsenseamplifieroutput.IADAPTvoltageis16timesthedifferentialvoltageacrossACP-ACN.Placea

100-pForlessceramicdecouplingcapacitorfromIADAPTtoAGND.
Chargecurrentsetinput.ThevoltageratioofSRSETvoltageversusVREFvoltageprogramsthechargecurrent

outputofanexternalDACtoSRSETpin.
Batteryvoltageremotesense.Directlyconnectakelvinsensetracefromthebatterypackpositiveterminaltothe

filterhigh-frequencynoise.
Chargecurrentsenseresistor,negativeinput.A0.1-µFceramiccapacitorisplacedfromSRNtoSRPtoprovide

filtering.
Chargecurrentsenseresistor,positiveinput.A0.1-µFceramiccapacitorisplacedfromSRNtoSRPtoprovide

differential-modefiltering.A0.1-µFceramiccapacitorisplacedfromSRPpintoAGNDforcommon-modefiltering.

Dynamicpowermanagement(DPM)inputcurrentloopactive,open-drainoutputstatus.Logiclowindicatesinput

differentpullup-supplyrail.
Powerground.Groundconnectionforhigh-currentpowerconverternode.OnPCBlayout,connectdirectlytosource

AGNDthroughthePowerPadunderneaththeIC.

PWMlowsidedriverpositive6-Vsupplyoutput.Connecta1-µFceramiccapacitorfromREGNtoPGND,closetothe
IC.Useforhigh-sidedriverbootstrapvoltagebyconnectingasmall-signalSchottkydiodefromREGNtoBTST.

PWMhighsidedrivernegativesupply.Connecttothephaseswitchingnode(junctionofthelow-sidepower

fromPHtoBTST.

PWMhighsidedriverpositivesupply.Connecta0.1-µFbootstrapceramiccapacitorfromBTSTtoPH.Connecta
smallbootstrapSchottkydiodefromREGNtoBTST.

currentsenseamplifierisactivewhentheACDETpinvoltageisgreaterthan0.6V.

ADAPT

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........................................................................................................................................................................................................SLUS838–MAY2009

Table1.TERMINALFUNCTIONS–24-PINQFN(continued)

TERMINAL

NAMENO.

PowerPad™PowerPadtotheboard,andhaveviasonthePowerPadplaneconnectingtoAGNDandPGNDplanes.Italso

DESCRIPTION

ExposedpadbeneaththeIC.AGNDandPGNDstar-connectedonlyatthePowerPadplane.Alwayssolder

servesasathermalpadtodissipatetheheat.

bq24704

ABSOLUTEMAXIMUMRATINGS

overoperatingfree-airtemperaturerange(unlessotherwisenoted)

PVCC,ACP,ACN,SRP,SRN,BAT–0.3to30
PH–1to30

Voltagerange–0.3to7V

MaximumdifferencevoltageACP–ACN,SRP–SRN,AGND–PGND–0.5to0.5V
Junctiontemperaturerange–40to155
Storagetemperaturerange–55to155

(1)Stressesbeyondthoselistedunderabsolutemaximumratingsmaycausepermanentdamagetothedevice.Thesearestressratings

only,andfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunderrecommendedoperating
conditionsisnotimplied.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability.

(2)AllvoltagesarewithrespecttoGNDifnotspecified.Currentsarepositiveinto,negativeoutofthespecifiedterminal.ConsultPackaging

Sectionofthedatabookforthermallimitationsandconsiderationsofpackages.

REGN,LODRV,VADJ,ACSET,SRSET,ACDET,ISYNSET,CHGEN,
CELLS,ACGOOD,DPMDET,IADAPT

VREF–0.3to3.6
BTST,HIDRVwithrespecttoAGNDandPGND–0.3to36

(1)(2)

VALUEUNIT

RECOMMENDEDOPERATINGCONDITIONS

overoperatingfree-airtemperaturerange(unlessotherwisenoted)

MINNOMMAXUNIT

PH–124
PVCC,ACP,ACN,SRP,SRN,BAT024
REGN,LODRV,VADJ06.5

VoltagerangeV

Maximumdifferencevoltage:ACP–ACN,SRP–SRN–0.30.3V
Junctiontemperaturerange–40125
Storagetemperaturerange–55150

VREF03.3
ACSET,SRSET,ACDET,ISYNSET,CHGEN,CELLS,ACGOOD,DPMDET,

IADAPT
BTST,HIDRVwithrespecttoAGNDandPGND030
AGND,PGND–0.30.3

05.5

°C

°C

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bq24704

Not Recommended for New Designs

SLUS838–MAY2009........................................................................................................................................................................................................

ELECTRICALCHARACTERISTICS

7V≤V

OPERATINGCONDITIONS

V

PVCC_OP

CHARGEVOLTAGEREGULATION

V

BAT_REG_RNG

V

ADJ_OP

CHARGECURRENTREGULATION

V

IREG_CHG

V

SRSET_OP

INPUTCURRENTREGULATION

V

IREG_DPM

V

ACSET_OP

VREFREGULATOR

V

VREF_REG

I

VREF_LIM

REGNREGULATOR

V

REGN_REG

I

REGN_LIM

ADAPTERCURRENTSENSEAMPLIFIER

V

ACP/N_OP

V

IADAPT

I

IADAPT

A

IADAPT

I

IADAPT_LIM

C

IADAPT_MAX

(1)I

≤24V,0°C<TJ<+125°C,typicalvaluesareatTA=25°C,withrespecttoAGND(unlessotherwisenoted)

PVCC

ADAPTER

istheinputadaptercurrentregulationsetting(refertoEquation3).

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PARAMETERTESTCONDITIONSMINTYPMAXUNIT

PVCCInputvoltageoperatingrange524V

BATvoltageregulationrange4V-4.512Vpercell,times2,3,4cell818V
VADJvoltagerange0REGNV

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%

ChargevoltageregulationsettodefaulttoVADJconnectedtoREGN,8.4V,12.6

4.2VpercellV,16.8V

ChargecurrentregulationdifferentialV
voltagerange

IREG_CHG

=V

–V

SRP

SRN

–0.5%0.5%

0100

SRSETvoltagerange0VREFV

Chargecurrentregulationaccuracy

Adaptercurrentregulationdifferential
voltagerange

V

IREG_CHG

V

IREG_CHG

V

IREG_CHG

V

IREG_CHG

V

IREG_DPM

=40–100mV–3%3%
=20mV–5%5%
=5mV–25%25%
=1.5mV(V

=V

ACP

–V

≥4V)–33%33%

BAT

ACN

0125mV

ACSETvoltagerange0VREFV

V

IREG_DPM

V

Inputcurrentregulationaccuracy

VREFregulatorvoltageV
VREFcurrentlimitV

REGNregulatorvoltage5.65.96.2V

REGNcurrentlimitV

IREG_DPM

V

IREG_DPM

V

IREG_DPM

ACDET

VREF

V

ACDET

PVCC>10V

REGN

=40–125mV–3%3%
=20mV–5%5%
=5mV–25%25%
=1.5mV–33%33%

>0.6V,0-30mA3.2673.33.333V

=0V,V

>0.6V3575mA

ACDET

>0.6V,0-75mA,

=0V,V

>0.6V90135mA

ACDET

InputcommonmoderangeVoltageonACP/ACN024V
IADAPToutputvoltagerange02V
IADAPToutputcurrent01mA
CurrentsenseamplifiervoltagegainA

Adaptercurrentsenseaccuracyatthe
condition
V

<1.5VxI

ACP-ACN

ADAPTER

(1)

xR

AC

OutputcurrentlimitV

=V

IADAPT

V
V
V
V

=40–125mV–2%2%

ACP-ACN

=20mV–3%3%

ACP-ACN

=5mV–25%25%

ACP-ACN

=1.5mV–30%30%

ACP-ACN

=0V1mA

IADAPT

/V

IADAPT

ACP-ACN

16V/V

MaximumoutputloadcapacitanceForstabilitywith0mAto1mAload100pF

mV

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........................................................................................................................................................................................................SLUS838–MAY2009

ELECTRICALCHARACTERISTICS(continued)

7V≤V

ACDETCOMPARATOR

V

PVCC-BAT_OP

V

ACDET_CHG

V

ACDET_CHG_HYS

V

ACDET_BIAS

V

ACDET_BIAS_HYS

OPEN-DRAINLOGICOUTPUTPINCHARACTERISTICS(ACGOOD)

V

O(LO)

PVCC/BATCOMPARATOR

V

PVCC-BAT_FALL

V

PVCC-BAT__HYS

INPUTUNDERVOLTAGELOCK-OUTCOMPARATOR(UVLO)

UVLO

BATOVERVOLTAGECOMPARATOR

V

O

CHARGEOVERCURRENTCOMPARATOR

V

OC

THERMALSHUTDOWNCOMPARATOR

T

SHUT

T

SHUT_HYS

PWMHIGHSIDEDRIVER(HIDRV)

R

DS(on)

V

BTST_REFRESH

(2)Specifiedbydesign.

≤24V,0°C<TJ<+125°C,typicalvaluesareatTA=25°C,withrespecttoAGND(unlessotherwisenoted)

PVCC

PARAMETERTESTCONDITIONSMINTYPMAXUNIT

DifferentialVoltagefromPVCCtoBAT–2024V

ACDETadapter-detectrisingthreshold2.3762.402.424V

ACDETfallinghysteresisV
ACDETrisingdeglitch

(2)

ACDETfallingdeglitchV

ACDETenable-biasrisingthreshold0.560.620.68V

AdapterpresentfallinghysteresisV
ACDET_BIASrisingdeglitch
ACDET_BIASfallingdeglitchV

OutputlowsaturationvoltageSinkCurrent=4mA0.5V
ACGOODfallingdelay V
ACGOODrisingdelayV

PVCCtoBATfallingthresholdV

PVCCtoBAThysteresis50mV
PVCCtoBATRisingDeglitchV
PVCCtoBATFallingDeglitchV

ACUndervoltagerisingthresholdMeasureonPVCC3.544.5V
ACUndervoltagehysteresis,falling260mV

Overvoltagerisingthreshold
Overvoltagefallingthreshold

ChargeovercurrentrisingthresholdAspercentageofI
MinimumCurrentLimit(SRP-SRN)50mV

ThermalshutdownrisingtemperatureTemperatureIncreasing155
Thermalshutdownhysteresis,falling20

Highsidedriverturn-onresistanceV
Highsidedriverturn-offresistanceV
BootstraprefreshcomparatorthresholdV

voltagepulseisrequested

bq24704

Minvoltagetoenablecharging,
V

rising

ACDET

falling40mV

ACDET

V

rising0.91.21.5s

ACDET

falling10µs

ACDET

Minvoltagetoenableallbias,V
rising

falling20mV

(2)

(2)

(2)

ACDET

V

rising10

ACDET

falling10

ACDET

rising0.91.21.5s

ACDET

falling10µs

ACDET

–V

PVCC

Charger

PVCC

PVCC

AspercentageofV

BTST

BTST

BTST

fallingtodisable140185240mV

BAT

–V

>V

BAT

PVCC-BAT_RISE

–V

<V

BAT

PVCC-BAT_FALL

BAT_REG

REG_CHG

–V

=5.5V,testedat100mA36

PH

–V

=5.5V,testedat100mA0.71.4

PH

–V

whenlowsiderefresh

PH

ACDET

µs

7911ms

6µs

104%
102%

145%

°C

Ω

4V

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Not Recommended for New Designs

SLUS838–MAY2009........................................................................................................................................................................................................

ELECTRICALCHARACTERISTICS(continued)

7V≤V

PWMLOWSIDEDRIVER(LODRV)

R

DS(on)

PWMDRIVERSTIMING

PWMOSCILLATOR

F

SW

V

RAMP_HEIGHT

QUIESCENTCURRENT

I

OFF_STATE

I

AC

INTERNALSOFTSTART(8stepstoregulationcurrent)

CHARGERSECTIONPOWER-UPSEQUENCING

ISYNSETAMPLIFIERANDCOMPARATOR(SYNCHRONOUSTONON-SYNCHRONOUSTRANSITION)

V

ISYNSET

LOGICIOPINCHARACTERISTICS(CHGEN)

V

IN(LO)

V

IN(HI)

I

BIAS

LOGICINPUTPINCHARACTERISTICS(CELLS)

V

IN(LO)

V

IN(MID)

V

IN(HI)

I

BIAS_FLOAT

OPEN-DRAINLOGICOUTPUTPINCHARACTERISTICS(DPMDET)
V

O(LO)

≤24V,0°C<TJ<+125°C,typicalvaluesareatTA=25°C,withrespecttoAGND(unlessotherwisenoted)

PVCC

PARAMETERTESTCONDITIONSMINTYPMAXUNIT

Lowsidedriverturn-onresistanceREGN=6V,testedat100mA36
Lowsidedriverturn-offresistanceREGN=6V,testedat100mA0.61.2

DriverDeadTime—Deadtimewhen
switchingbetweenLODRVandHIDRV.No30ns
loadatLODRVandHIDRV

PWMswitchingfrequency240300360kHz
PWMrampheightAspercentageofPVCC6.6%PVCC

V

=16.8V,V

BAT

V

>5V,TJ=85°C

Totaloff-statebatterycurrentfromSRP,
SRN,BAT,VCC,BTST,PH,etc.

AdapterquiescentcurrentV

PVCC

V

=16.8V,V

BAT

V

>5V,TJ=125°C

PVCC

=20V,chargedisabled11.5mA

PVCC

Softstartsteps8step
Softstartsteptime1.7ms

Delayfromwhenadapterisdetected

Charge-enabledelayafterpower-uptowhenthechargerisallowedtoturn0.91.21.5s

on

I

AccuracyV

SYN

(SRP-SRN)

=5mV–20%20%

ISYNSETpinvoltage1V
ISYNSETrisingdeglitch20µs
ISYNSETfallingdeglitch640µs

Inputlowthresholdvoltage0.8V
Inputhighthresholdvoltage2.1
InputbiascurrentV

=0toV

CHGEN

Inputlowthresholdvoltage,3cellsCELLSvoltagefallingedge0.5

Inputmidthresholdvoltage,2cells0.81.8V

CELLSvoltagerisingforMIN,

CELLSvoltagefallingforMAX
Inputhighthresholdvoltage,4cellsCELLSvoltagerising2.5
Inputbiasfloatcurrentfor2-cellselectionV=0toV

REGN

OutputlowsaturationvoltageSinkCurrent=5mA0.5V
Delay,rising/falling7911ms

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Ω

<0.6V,

ACDET

<0.6V,

ACDET

REGN

710

µA

711

1µA

–11µA

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-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

bq24704

Not Recommended for New Designs

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........................................................................................................................................................................................................SLUS838–MAY2009

TYPICALCHARACTERISTICS

TableofGraphs

(1)

YXFigure

VREFLoadandLineRegulationvsLoadCurrentFigure3
REGNLoadandLineRegulationvsLoadCurrentFigure4
BATVoltagevsVADJ/VREFRatioFigure5
ChargeCurrentvsSRSET/VREFRatioFigure6
InputCurrentvsACSET/VREFRatioFigure7
BATVoltageRegulationAccuracyvsChargeCurrentFigure8
BATVoltageRegulationAccuracyFigure9
ChargeCurrentRegulationAccuracyFigure10
InputCurrentRegulation(DPM)AccuracyFigure11
V

InputCurrentSenseAmplifierAccuracyFigure12

IADAPT

InputRegulationCurrent(DPM),andChargeCurrentvsSystemCurrentFigure13
TransientSystemLoad(DPM)ResponseFigure14
ChargeCurrentRegulationvsBATVoltageFigure15
EfficiencyvsBatteryChargeCurrentFigure16
BatteryRemoval(fromConstantCurrentMode)Figure17
REFandREGNStartupFigure18
ChargeronAdapterRemovalFigure19
ChargeEnable/DisableandCurrentSoft-StartFigure20
NonsynchronoustoSynchronousTransitionFigure21
SynchronoustoNonsynchronousTransitionFigure22
Near100%DutyCycleBootstrapRechargePulseFigure23
BatteryShortedChargerResponse,OverCurrentProtection(OCP)andChargeCurrentRegulationFigure24
ContinuousConductionMode(CCM)SwitchingWaveformsFigure25
DiscontinuousConductionMode(DCM)SwitchingWaveformsFigure26
DPMDETResponsewithTransientSystemLoadFigure27

(1)TestresultsbasedonFigure2applicationschematic.VIN=20V,V

unlessotherwisespecified.

=3-cellLi-Ion,I

BAT

=3A,I

CHG

ADAPTER_LIMIT

=4A,TA=25°C,

VREFLOADANDLINEREGULATIONREGNLOADANDLINEREGULATION

vsvs

LoadCurrentLOADCURRENT

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Figure3.Figure4.

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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/V Ratio

REF

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/V Ratio

REF

VoltageRegulation-V

VADJ=0-V ,
4-Cell,

NoLoad

REF

V =16.8V

reg

-0.2

-0.1

0

0.1

0.2

0

2000

4000

6000

8000

ChargeCurrent-mA

RegulationError-%

0

1

2

3

4

6

7

8

9

10

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

ACSET/V Ratio

REF

InputCurrentRegulation- A

5

ACSET Varied,
4-Cell,
Vbat=16V

13

12

11

1.00.9

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-V

REF

-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

bq24704

Not Recommended for New Designs

SLUS838–MAY2009........................................................................................................................................................................................................

BATVOLTAGECHARGECURRENT

vsvs

VADJ/VREFRATIOSRSET/VREFRATIO

Figure5.Figure6.

INPUTCURRENTBATVOLTAGEREGULATIONACCURACY

vsvs

ACSET/VREFRATIOCHARGECURRENT

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Figure7.Figure8.

BATVOLTAGEREGULATIONACCURACYCHARGECURRENTREGULATIONACCURACY

Figure9.Figure10.

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