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V

IN

LP8556

MCU

VBOOST

SW

1.1 ”9

OUT

/ V

IN

”15

L1

D1

VDD

C

IN

C

OUT

LED1

LED2

LED3

LED4

LED5

LED6

GNDs

PWM

SDA

SCL

ISET

FSET

VLDO

C

VLDO

R

FSET

R

ISET

2.7V - 20V

7V ± 43V

EN / VDDIO

EN / V

DDIO

1.62V ± 3.6V

V

OUT

Optional

Product

Folder

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Now

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Reference

Design

AnIMPORTANTNOTICEattheendofthisdatasheetaddressesavailability,warranty,changes,useinsafety-criticalapplications,

intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA.

LP8556

SNVS871M–JULY2012–REVISEDJUNE2020

LP8556High-EfficiencyLEDBacklightDriverForTablets

1

1Features

1

•High-efficiencyDC/DCboostconverterwith

integrated0.19-ΩpowerMOSFETandthree

switchingfrequencyoptions:312kHz,625kHz,

and1250kHz

•2.7-Vto36-VBoostswitchinputvoltagerange

supportsmulti-cellLi-Ionbatteries

(2.7-Vto20-VV

DD

inputrange)

•7-Vto43-VBoostswitchoutputvoltagerange

supportsasfewas3WLEDsinseriesper

channelandasmanyas12

•Configurablechannelcount(1to6)

•Upto50mAperchannel

•PWMand/orI

2

Cbrightnesscontrol

•Phase-shiftPWMmodereducesaudiblenoise

•AdaptivedimmingforhigherLEDdriveoptical

efficiency

•Programmableedge-ratecontrolandspread

spectrumschememinimizeswitchingnoiseand

improveEMIperformance

•LEDfault(shortandopen)detection,UVLO,TSD,

OCP,andOVP(upto6thresholdoptions)

•Availableintiny20-pin,0.4-mmpitchDSBGA

packageand24-pin,0.5-mmpitchWQFN

package

2Applications

LEDbacklightsfortabletLCDs

space

SimplifiedSchematic

3Description

TheLP8556deviceisawhite-LEDdriverfeaturingan

asynchronousboostconverterandsixhighprecision

currentsinksthatcanbecontrolledbyaPWMsignal

oranI

2

Cmaster.

Theboostconverterusesadaptiveoutputvoltage

controlforsettingtheoptimalLEDdrivervoltagesas

lowas7Vandashighas43V.Thisfeature

minimizesthepowerconsumptionbyadjustingthe

outputvoltagetothelowestsufficientlevelunderall

conditions.Theconvertercanoperateatthree

switchingfrequencies:312kHz,625kHz,and

1250kHz,whichcanbesetwithanexternalresistor

orpre-configuredviaEPROM.Programmableslew

ratecontrolandspreadspectrumschememinimize

switchingnoiseandimproveEMIperformance.

LEDcurrentsinkscanbesetwiththePWMdimming

resolutionofupto15bits.Proprietaryadaptive

dimmingmodeallowshighersystempowersaving.In

addition,phaseshiftedLEDPWMdimmingallows

reducedaudiblenoiseandsmallerboostoutput

capacitors.

TheLP8556devicehasafullsetoffault-protection

featuresthatensurerobustoperationofthedevice

andexternalcomponents.Thesetconsistsofinput

undervoltagelockout(UVLO),thermalshutdown

(TSD),overcurrentprotection(OCP),upto6levelsof

overvoltageprotection(OVP),LEDopenandshort

detection.

TheLP8556deviceoperatesovertheambient

temperaturerangeof–30°Cto+85°C.Itisavailable

inspace-saving20-pinDSBGAand24-padWQFN

packages.

DeviceInformation

(1)

PARTNUMBERPACKAGEBODYSIZE

LP8556

DSBGA(20)2.401mm×1.74mm(MAX)

WQFN(24)4.00mm×4.00mm(NOM)

(1)Forallavailablepackages,seetheorderableaddendumat

theendofthedatasheet.

Produktspecifikationer