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LP8555

SW_A

FB_A

VLDO

GNDs

EN/VDDIO

ISET/SCL

PWM/INT

LEDA1

LEDA2

LEDA3

LEDA4

LEDB3

LEDB4

L1D1

7 - 28V

2.7V ± 20V

C

VLDO

VDD

V

BATT

FSET/SDA

LEDB5

LEDB6

SW_B

FB_B

L2D2

2.7V ± 20V

V

BATT

LEDA5

LEDA6

LEDB1

LEDB2

1.3 9

OUT

/ V

IN

10

V

OUT_A

7 - 28V

1.3 9

OUT

/ V

IN

10

V

OUT_B

C

VDD

EN

SDA

SCL

VDDIO

R

PULL-UP

INT

R

PULL-UP

LED BANK ALED BANK B

LCD Display

C

OUT_A

C

IN_A

C

OUT_B

C

IN_B

80

82

84

86

88

90

92

020406080100

LED Drive Efficiency (%)

Brightness (%)

VIN = 3.0 V

VIN = 3.7 V

VIN = 4.2 V

VIN = 5.4 V

VIN = 7.4 V

VIN = 8.4 V

C002

Inductor: IHLP2525CZER6R8M01

Product

Folder

Sample &

Buy

Technical

Documents

Tools &

Software

Support &

Community

LP8555

SNVS857–FEBRUARY2014

LP8555High-EfficiencyLEDBacklightDriverforTabletPCs

1Features3Description

TheLP8555isahighefficiencyLEDdriverwith

1

•DualHigh-EfficiencyDC/DCBoostConverters

integrateddualDC-DCboostconverters.Ithas12

•2.7-Vto20-VVDDRange

high-precisioncurrentsinksthatcanbecontrolledby

•1250-mAHigh-PrecisionLEDCurrentSinksWith

aPWMinputsignal,anI

2

Cmaster,orboth.

12-BitBrightnessControl

Dual-boostconfigurationofLP8555sharestheload

•AdaptiveLEDCurrentSinkHeadroomControlsfor

totwoinductorsandallowsthinneroverallsolution

MaximumSystemEfficiency

sizeandbetterefficiencycomparedtosingle-boost

solutions.12LEDstringsallowsdrivinghighnumber

•LEDStringCountAuto-Detection

ofLEDswithoptimalefficiencysinceboost

•Phase-ShiftedPWMModeforReducedAudible

conversionratiocanbekeptlow.

Noise

Theboostconverterhasadaptiveoutputvoltage

•PWMInputDuty-Cycleand/orI

2

C-Register

controlbasedontheLEDcurrentsinkheadroom

BrightnessControl

voltages.Thisfeatureminimizesthepower

•HybridPWMandCurrentDimmingforHigherLED

consumptionbyadjustingthevoltagetolowest

DriveOpticalEfficiency

sufficientlevelinallconditions.

•FlexibleCABCSupport

TheLEDstringauto-detectfunctionenablesuseof

•EPROM,I

2

C-Register,orExternalResistorsfor

thesamedeviceinsystemswith2to12LEDstrings

Configuration

forthemaximumdesignflexibility.ProprietaryHybrid

PWMandCurrentdimmingmodeenablesadditional

•ImprovedBoostEMIPerformancewithSlew-Rate

systempowersavings.Phase-shiftPWMallows

Control,SpreadSpectrum,andPhase-Shifted

reducedaudiblenoiseandsmallerboostoutput

Switching

capacitors.FlexibleCABCsupportcombines

•ExtensiveFaultDetectionSchemes

brightnesslevelselectionsbasedonthePWMinput

andI

2

Ccommands.

2Applications

DeviceInformation

•TabletLCDDisplayLEDBacklight

ORDERNUMBERPACKAGEBODYSIZE

LP8555YFQRDSBGA(36)2,478mmx2,478mm

4SimplifiedSchematic

LEDDriveEfficiency

1

AnIMPORTANTNOTICEattheendofthisdatasheetaddressesavailability,warranty,changes,useinsafety-criticalapplications,

intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA.

Produktspecifikationer