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MCU

LP8551

SW

FB

V

LDO

GNDs

EN

ISET

V

DDIO

PWM

SCLK

SDA

OUT1

OUT2

OUT3

OUT4

L1D1

10 V ± 40 V

5.5 V ± 22 V

5V

FSET

15 éH

210 mA ± 400 mA

C

OUT

C

IN

10 éF

4.7 éF

C

VLDO

1 éF

V

DDIO

reference voltage

FAULT

Can be left floating

if not used

39 pF

VIN

R

ISET

R

FSET

V

BATT

Product

Folder

Sample &

Buy

Technical

Documents

Tools &

Software

Support &

Community

LP8551

SNVS673E–APRIL2010–REVISEDSEPTEMBER2014

LP8551High-EfficiencyLEDBacklightDriverforNotebooks

1Features3Description

TheLP8551isawhiteLEDdriverwithintegrated

1

•High-VoltageDC/DCBoostConverterwith

boostconverter.Ithasfouradjustablecurrentsinks

IntegratedFET;FourSwitchingFrequency

whichcanbecontrolledbyPWMinputorwithI

2

C-

Options:156/312/625/1250kHz

compatibleserialinterface.

•2.7-Vto22-VInputVoltageRangetoSupport1x

Theboostconverterhasadaptiveoutputvoltage

to5xCellLi-IonBatteries

controlbasedontheLEDdrivervoltages.This

•50-mAHigh-PrecisionLEDCurrentSinks

featureminimizesthepowerconsumptionby

•AdaptiveLEDCurrentSinkHeadroomControlfor

adjustingthevoltagetolowestsufficientlevelinall

MaximumSystemEfficiency

conditions.

•ProgrammablePWMResolution8to13Bits

LEDoutputshave8-bitcurrentresolutionandupto

13-bitPWMresolutiontoachievesmoothandprecise

•I

2

CandPWMInputDutyCycleBrightnessControl

brightnesscontrol.ProprietaryPhaseShiftPWM

•PWMOutputFrequencyandLEDCurrentSet

controlisusedforLEDoutputstoreducepeak

ThroughResistors

currentfromtheboostconverter,thusmakingthe

•4LEDOutputswithLEDFault(short/open)

boostcapacitorssmaller.ThePhaseShiftingscheme

Detection

alsoeliminatesaudiblenoise.

•LowInputVoltage,Overtemperature,Overcurrent

InternalEEPROMisusedforstoringtheconfiguration

Detection,andShutdown

data.Thismakesitpossibletohaveminimum

•MinimumNumberofExternalComponents

externalcomponentcountandmakethesolutionvery

small.

2Applications

TheLP8551hassafetyfeatureswhichmakeit

possibletodetectLEDoutputswithopenorshort

•NotebookandTabletLCDDisplayLEDBacklight

fault.Aswell,lowinputvoltageandboostovercurrent

•LEDLighting

conditionsaremonitored,andchipisturnedoffin

caseoftheseevents.Thermalde-ratingfunction

preventsoverheatingofthedevicebyreducing

backlightbrightnesswhensettemperaturehasbeen

reached.

DeviceInformation

(1)

PARTNUMBERPACKAGEBODYSIZE(MAX)

LP8551DSBGA(25)2.49mmx2.49mm

(1)Forallavailablepackages,seetheorderableaddendumat

theendofthedatasheet.

SimplifiedSchematicLEDDriveEfficiency

1

AnIMPORTANTNOTICEattheendofthisdatasheetaddressesavailability,warranty,changes,useinsafety-criticalapplications,

intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA.

Produktspecifikationer