PR4103A [PREMA]

High Power LED Buck Converter;


型号：	PR4103A
厂家：	Prema
描述：	High Power LED Buck Converter
文件：	总8页 (文件大小：416K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LEDDriverPR4103

HighPowerLEDBuckConverter

ThePR4103isaLEDbuckdriverfordrivingone

or several high power LEDs in series. The

supply voltage can be up to 20V, with an

output current of more than 1A using an

external n-channel MOSFET switching

transistor.TheSOT23packageallowsmounting

onsmall-sizedboards.

APPLICATIONS

•Halogenlamporfilament

•bulbreplacementbyLEDs

•Generalillumination

•Warninglights

FEATURES

•Automotivelighting

•LCDbacklighting

•Adjustableoutputcurrentof1Aandmore

•Supplyvoltageupto20V

•Indicatorsigns

•Undervoltagelockout

CIRCUITDIAGRAM

Vcc

8.4V ... 20V

Vcc

CLED

One or

more LEDs

CIN

Gnd

NDRV

Vsense

RVsense

Rsense

PR4103

ABSOLUTEMAXIMUMRATINGS

Parameter

Min Max

Units

[V]

VCC,VDI(nodamage)

Allotherpins

-0.3

[V]

OperatingChipTemperatureRange(overtemperatureprotection) -20

125

150

[°C]

[kV]

StorageTemperatureRange

-55

ElectrostaticDischarge(ESD)Protection

©PREMASemiconductorGmbH2006-2014Irev.1014

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LEDDriverPR4103

ICPINs

PINCONFIGURATIONS

Vsense

GND

Vcc

NDRV

GND

n.c.

Vcc

n.c.

Vsense

n.c.

NDRV

PR4103A:PackageSOT23-5

Topsidemarking:"SC"withlotcode

PR4103B:PackageSOP8

Topsidemarking:"PR4103"

"SC10"+versioncode

PINDESCRIPTIONS

PINNo. PINNo.

PR4103A PR4103B

PINName PINFunctionDescription

Vcc

Supplyvoltage

Internal7Vlinearregulatoroutput.Connectacapacitorof

3.3µFtoGND.Voltageisnotforexternaluse.

NDRV

GND

Gateconnectionforanexternaln-channelMOSFET.

Ground

Feedbackforcontrollingtheoutputcurrent.Connectthis

pintotheseriesresistorR andthesenseresistor

R .

SENSE

VSENSE

VSense

TheexternalMOSFETisswitchedoffwhenthevoltageat

thispinishigherthanV .

SENSE

©PREMASemiconductorGmbH2006-2014Irev.1014

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LEDDriverPR4103

Characteristics

ELECTRICALCHARACTERISTICS

Vcc=12VDC,Ta=25°C,L=470µH(unlessotherwisenoted)

Symbol Parameter

Min

Typ Max Units

Vcc

Supplyvoltage

[V]

VDI Undervoltagedetection Start-up

Shut-off

9.0

[V]

8.0

5.0

8.4

3.0

Supplycurrent

[mA]

suppON

NDRV

GateoutputvoltageHIGH

5.8

[V]

OutputsourcecurrentatNDRV

[mA]

OUTsource

OutputsinkcurrentatNDRV

Operatingfrequency

[mA]

[kHz]

[mV]

OUTsink

130

ThresholdvoltageatR

200

SENSE

BLOCKDIAGRAM

©PREMASemiconductorGmbH2006-2014Irev.1014

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LEDDriverPR4103

ApplicationNotes

TYPICALAPPLICATIONWITHA12VACPOWERSUPPLYFORAMINIMUMBOARDSIZE

ThefollowingcircuitdrivesoneLEDfroma12VACsupply.ThiscircuitusesthePR4103AinSOT23package

andisoptimizedforalownumberofsmall-sizedexternalcomponentstohaveasmallPCB.LEDand

driveraresuppliedfromthefull-waverectifiedandsmoothedvoltage.Ripplesonthesupplyshouldbe

smallenoughtoavoidaperiodinwhichthevoltagebecomeslowerthantheLEDforwardvoltage,or

belowtheundervoltageshut-off.

WithR =0.24Ω,asutilizedinthediagram,theLEDcurrentisapprox.850mA.Forvariedtarget

SENSE

currentsseethefolloingsection“SelectionofR “.

SENSE

©PREMASemiconductorGmbH2006-2014Irev.1014

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LEDDriverPR4103

ApplicationNotes

SELECTIONOFTHEINPUTCAPACITORC

SELECTIONOFINDUCTORANDC

LED

TheinputcapacitorisnecessaryincaseofAC

supplyvoltagestosmooththesupplyvoltage.A

Selectionoftheinductorvaluedependsaloton

thesupplyvoltage,thenumberofconnected

valuebetween100µFand4700µFfornormal LEDs,butalsoontheallowedcurrentrippleand

ACandof470µFupto10000µFforphase-cut thedesiredefficiency.ForasmallerLEDcurrent

supplyvoltagesisrecommended.Inparallela

100nFcapacitorshouldbeplacedclosetotheIC

highervaluesabove660µHshouldbeused.In

casethataminimizedboardsizeisdesired

supplypins.Step-downregulatorsdrawcurrent inductorvaluesaround100µHmaybeselected

fromtheinputsupplyinpulseswithveryfast butefficiencyandLEDcurrentripplearenot

riseandfalltimes.Theinputcapacitorisalso

requiredtoreducetheresultingvoltageripple

atthePR4103inputandtoforcethisswitching

optimizedinthiscase.Thesaturationcurrentof

theinductorsmustbehigherthantheLEDpeak

current.AlowDCresistanceofthecoilavoids

currentintoatightlocalloop,minimizingEMI. additionallossofefficiency.

Theinputcapacitormusthavealowimpedance

AcapacitorvalueofCLEDbetween22µFand

attheswitchingfrequencytodothiseffectively, 1000µFinparalleltotheLEDisrecommended

anditshouldhaveanadequateripplecurrent to reduce the LED current ripple and avoid

rating.

exceedingtheLEDcurrentrating.

SELECTIONOFTHEEXTERNALMOSFET

doesnotworkinthismode.Whenthesupply

rises, the converter will resume normal

operation.

Then-channelMOSFETmusthaveagate

thresholdvoltageoflessthan3.8Vandalow

ONresistance.Toimprovethebehaviourofthe

module,longlinesbetweentheICandthe

transistorshouldbeavoided.

SELECTIONOFR ANDR

VSENSE

SENSE

The input V needs a series resistor

SENSE

R =1kΩwhiletheLEDcurrentisdefinedby

VSENSE

SELECTIONOFTHEEXTERNALDIODE

theselectionofR .Thenominalvalueofthe

SENSE

currentsenseresistorcanbecalculatedwith

thefollowingformula:

ASchottkydiodewithfastrecoveryisneeded

toreducethevoltagedrop.Thediodemustbe

abletocarrytheLEDcurrentflowingduringthe

OFFtimeofthedriver.Thereversevoltageof

thediodeshouldbehigherthantheinput

voltage.

V_SENSE

R_SENSE

I_LED

ThevalueofV canbefoundinthe

SENSE

„ElectricalCharacteristics“.

OPERATIONWITHINSUFFICIENTVOLTAGES

Forexample:WithanLEDcurrentof1Aand

V =200mV,R hasavalueof200mΩ.

Thefollowingtablegivessomeresistorvalues.

InoperationwithseveralLEDsinseries,itis

possiblethatthesupplyvoltageishigherthan

the undervoltage detection threshold, but

insufficient to drive the programmed LED

currentbecauseoftheLEDforwardvoltage.

ThenthedesiredLEDcurrentcanobviouslynot

be reached. In this case the MOSFET is

permanently switched through, allowing the

maximumLEDcurrentpossible,butalwaysless

than the current setpoint. The PWM control

SENSE

LEDCurrent

SENSE

350mA

700mA

1000mA

0.571Ω

0.286Ω

0.200Ω

©PREMASemiconductorGmbH2006-2014Irev.1014

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LEDDriverPR4103

AvailablePackages

SOT23-5(PR4103A)

SO8LPACKAGE(PR4103B)

Package

D E H A A1 A2 e e1 B/b L w

SOT23-5 Nom. 2.90 1.60 2.80 1.10 0.05 0.80 0.95 1.90 0.40 0.20

PR4103A Max. 3.10 1.80 3.00 1.30 0.10

2.10 0.50

SOP08L Nom. 4.90 3.90 6.00 1.75 0.15

PR4103B Max.

1.27

0.41 0.72 4°

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LEDDriverPR4103

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LEDDriverPR4103

Deliveryindieformuponrequest.

AllpartsdeliveredcomplywithRoHS.Finishispuretin.

Disclaimer

InformationprovidedbyPREMAisbelievedtobeaccurateandcorrect.However,noresponsibilityisassumedby

PREMAforitsuse,norforanyinfringementsofpatentsorotherrightsofthirdpartieswhichmayresultfromitsuse.

PREMAreservestherightatanytimewithoutnoticetochangecircuitryandspecifications.

LifeSupportPolicy

PREMASemiconductorsproductsarenotauthorizedforuseascriticalcomponentsinlifesupportdevicesor

systemswithouttheexpresswrittenapprovalofPREMASemiconductor.Asusedherein:

1.Lifesupportdevicesorsystemsaredevicesorsystemswhich,(a)areintendedforsurgicalimplantintothebody,

or(b)supportorsustainlife,andwhosefailuretoperformwhenproperlyusedinaccordancewithinstructionsfor

useprovidedinthelabeling,canbereasonablyexpectedtoresultinasignificantinjurytotheuser.

2.Acriticalcomponentisanycomponentofalifesupportdeviceorsystemwhosefailuretoperformcanbe

reasonablyexpectedtocausethefailureofthelifesupportdeviceorsystem,ortoaffectitssafetyoreffectiveness.

PREMASemiconductorGmbH

Robert-Bosch-Str.6

55129Mainz Germany

Phone:+49-6131-5062-0

Fax:+49-6131-5062-220

Email:prema@prema.com Website:www.prema.com

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