AN-1937 LM3433 10A to 40A LED Driver Evaluation Board …

1 User's GuideSNVA386D March2009 RevisedMay2013AN-1937LM343310 Ato40 ALEDD riverEvaluationBoard1 IntroductionTheLM3433is anadaptiveconstanton-timeDC/DCbuckconsta ntcurrentcontrollerdesignedtodriveahighb rightnessLED(HBLED) is a truecurrentsourcethatprovidesa designedtoprovidea constantcurrentin therangeof10 Ato60A(althoughtheboardis thermallylimitedtoapproximately40 Acontinuousoperation)andcanconnectdirect lytoaLuminusDevices, is positivevoltagewithrespecttoGNDis requiredforthebiasandcontrolcircuitryand anegativevoltagewithrespecttoGNDis (anyhighcurrent12 Vsupplywillwork).

2 ThepositivevoltagewithrespecttoGNDontheb oardis suppliedbytheLM5002circuit(seebelow).Ini tiallytheoutputcurrentis shortmaybeconnectedbetweenLED+andLED-,th enusea currentprobeandturnthePOTclockwiseuntilt hedesiredcurrentis ,ENA,is , levelshiftedsothattheoutputthatsuppliest heLM3433biascircuitrywillremainat+5 VwithrespecttoGNDregardlessofwhereVEEis in small5 Vsideblowerfan(SunonpartnumberB0502 AFB2-8)tohelpkeeptheinductor,andtherefor etheboardtosomedegree,coolerif a system, a a registeredtrademarkofLuminusDevices, March2009 RevisedMay2013AN-1937LM343310 Ato40 ALEDD riverEvaluationBoardSubmitDocumentationF eedbackCopyright 2009 2013,TexasInstrumentsIncorporatedIRMS =VLED(|VEE|-VLED)|VEE| designedsothattheLEDcurrentcanbesetin (RSENSE) 2m resistorcomesmountedontheboard(five10m resistorsin parallel) theSection8 thecurrentcanbesetusingthefollowingequat ion.

3 ILED= VSENSE/RSENSE(1) capableofhighspeedPWMdimmingin accomplishedbyshortingacrosstheLEDwitha FET(s). usingdimmingFETsremotelyplacedclosetothe LED(STRONGLY recommended).If theFETscannotbeplaceddirectlynexttotheLE Dthensomeformofsnubbermayberequiredtopre ventdamagetotheLM3433,LM5111, ,C17,andR32maybeusedtopopulatea pulledhighthedimmingFETis is pulledlowthedimmingFETis scopeplotofPWMdimmingis includedin Section8 showing120 Hzdimmingat20% thepowerFETsanddimmingFETsbyusingtheLM51 11gatedriverstoincreasethegatedrivecurre ntaswellasthegatevoltageforminimumRDS(ON ).

4 PoweredbyusingD6andC25toforma chargepumptogeneratea positivevoltageaboveGNDthatisapproximate lyequalto|VEE|.Thisvoltageis highgatedrivecurrentcapabilityanda (ON) :U5,U6,R33,D6,C22, a highvoltagegatedriveris used(VCC= |VEE|+ VfwhereVfif theLEDforwardvoltagedrop)thenD5andC23may beaddedtopowerthegatedriverICdirectlywit hthechargepumpandU6,D6, ,particularlywhenPWMdimming, verylong(upto50,000hours)thelongevityofa naluminumelectrolyticcapacitorcanbecomet hemainfactorin givenbythefollowingequation:(2)2AN-1937L M343310 Ato40 ALEDD riverEvaluationBoardSNVA386D March2009 RevisedMay2013 SubmitDocumentationFeedbackCopyright 2009 2013,TexasInstrumentsIncorporatedLifeACT UAL = LifeRATED X 2 TCORE - TACTUAL7( )

5 Particularshouldbeabletohandletheripplec urrentwithouta significantrisein goodruleofthumbis thatif thecasetemperatureofthecapacitoris 5 C abovetheambientboardtemperaturethentheca pacitoris notcapableofsustainingtheripplecurrentfo ritsfullratedlifetimeanda lifetimeratingata givencoretemperature,suchas5000hoursat10 5 C belowthistemperaturethecapacitoroperates atandshouldhalveforeach7 goodqualityaluminumelectrolyticcapacitor willalsohavea coretemperatureofapproximately3 C to5 C ,a capacitorratedfor5,000hoursat105 C thatis operatingin anambientenvironmentof85 C willhavea coretemperatureofapproximately90 C , (LifeACTUAL) canbefoundusingtheequation:(3)WhereLifeR ATEDis theratedlifetimeattheratedcoretemperatur eTCORE.

6 Forexample:If theambienttemperatureis 85 C thecoretemperatureis 85 C + 5 C = 90 C.(105 C - 90 C)/7 C = ^ 5,000* 22, ,000hoursormoreat105 March2009 RevisedMay2013AN-1937LM343310 Ato40 ALEDD riverEvaluationBoardSubmitDocumentationF eedbackCopyright 2009 2013, March2009 RevisedMay2013 SubmitDocumentationFeedbackCopyright 2009 2013, ,U4,U5LM5111 GateDriverMSOP-3 TIPowerPAD -8U6LM2937 LinearRegulatorSOT-2231 TIC1C0805C471K5 RACTUC apacitor0805470pF,50V1 KemetC2 LMK316BJ476ML-TCapacitor120647 F, ,C3b16SH150 MCapacitorMULTICAP150 F,16V2 SanyoC4a,C4b,C4c,GRM32ER61C226KE20 LCapacitor121022 F,16V6 MurataC4d,C4e,C4fC6,C34.

7 C35 GRM32ER61C476ME15 LCapacitor121047 F,16V3 MurataC7,C8, F,50V3 KemetC9,C17,C23,OPEN0805C24,C26,C27,C29, C30C10,C11,C20, F,16V6 MurataC21,C25,C33C120805YD105 KAT2 ACapacitor08051 F,16V1 AVXC13C0805C103K1 RACTUC apacitor080510nF, F, F,25V1 MurataC22 GRM21BR61C106KE15 Capacitor080510 F, F,50V1 AVXC28 OPEN1210D1,D2,D6,D7MA2YD2600 LDiodeSOD-12360V,800mA2 PanasonicD3 MBRS240LT3 DiodeSMB40V,2A1 ONSemiconductorD4 OPENSMBD5 OPENSOD-123J2B8B-EH-A(LF)(SN)Connector1 JSTS alesAmerica, * H, H,48A1 CoilcraftL3,L4,L5,L6,L7,HI1206T500R-10 FerriteBead120650 @100 MHz6 StewardL8L9,L10 OPEN1206L11 MPZ2012S101 AFerriteBead0805100 @100 MHz1 TDKP13352T-1-103 LFPotentiometerBOURNS210k 1 BournsQ1,Q2,Q3,Q4,SIE808DF-T1-E3 FETP olarPAK20V, 6 VishayQ5, ,Q9,Q13,OPENSOIC-8Q14,Q15,Q16,Q17,Q18Q10 ,Q11, March2009 RevisedMay2013AN-1937LM343310 Ato40 ALEDD riverEvaluationBoardSubmitDocumentationF eedbackCopyright 2009 2013, (continued)

8 1 PanasonicR3,R13,R30,ERJ-6 ENF1002 VResistor080510k 4 PanasonicR31R4 ERJ-6 GEYJ393 VResistor080539k 1 PanasonicR5 ERJ-6 GEYJ101 VResistor0805100 1 PanasonicR8 ERJ-6 ENF2002 VResistor080520k 1 PanasonicR11, 2 PanasonicR15a,R15b, 5 VishayR15c,R15d,R15eR17,R18,R19, 4 PanasonicR20R24 ERJ-6 GEYJ100 VResistor080510 1 PanasonicR25 ERJ-6 ENF7502 VResistor080575k 1 PanasonicR34 ERJ-6 GEYJ103 VResistor120610k 1 PanasonicR35 CRCW0805100 KFKEAR esistor1206100k 1 VishayR36 CRCW080524K0 FKEAR esistor120624k 1 VishayR14,R21,R22,OPEN0805R23,R32,R38,R3 9R40,R41,R42 ERJ-6 GEY0R00 VResistor08050 3 Panasonic-12V, "2 KeystoneADJ,PWM, "3 Keystone6AN-1937LM343310 Ato40 ALEDD riverEvaluationBoardSNVA386D March2009 RevisedMay2013 SubmitDocumentationFeedbackCopyright 2009 2013,TexasInstrumentsIncorporated-14-13- 12-11-10-986889092949698100 EFFICIENCY (%)VEE INPUT VOLTAGE (V) VOLTAGE (V)VSENSE (mV) (ILED= 18A,VLED= )ILED= 30 Anominal,VIN= 5V,VEE= -12 VToptrace:DIMinput,1V/div,DCBottomtrace.

9 ILED,10A/div,DCT = 2 March2009 RevisedMay2013AN-1937LM343310 Ato40 ALEDD riverEvaluationBoardSubmitDocumentationF eedbackCopyright 2009 2013, March2009 RevisedMay2013 SubmitDocumentationFeedbackCopyright 2009 2013, March2009 RevisedMay2013AN-1937LM343310 Ato40 ALEDD riverEvaluationBoardSubmitDocumentationF eedbackCopyright 2009 2013, March2009 RevisedMay2013 SubmitDocumentationFeedbackCopyright 2009 2013, March2009 RevisedMay2013AN-1937LM343310 Ato40 ALEDD riverEvaluationBoardSubmitDocumentationF eedbackCopyright 2009 2013,TexasInstrumentsIncorporatedIMPORTA NTNOTICET exasInstrumentsIncorporatedanditssubsidi aries(TI)reservetherighttomakecorrection s,enhancements,improvementsandotherchang estoitssemiconductorproductsandservicesp erJESD46,latestissue,andtodiscontinueany productorserviceperJESD48, (alsoreferredtohereinas components )

10 AresoldsubjecttoTI s ,in accordancewiththewarrantyin TI s ,testingofallparametersofeachcomponentis productsandapplications, ,eitherexpressorimplied,is grantedunderanypatentright,copyright,mas kworkright,orotherintellectualpropertyri ghtrelatingtoanycombination,machine,orpr ocessin licensetousesuchproductsorservicesora licensefroma thirdpartyunderthepatentsorotherintellec tualpropertyofthethirdparty,ora TIdatabooksordatasheetsis permissibleonlyif reproductionis withoutalterationandis accompaniedbyallassociatedwarranties,con ditions,limitations, is solelyresponsibleforcompliancewithallleg al,regulatoryandsafety-relatedrequiremen tsconcerningitsproducts,andanyuseofTIcom ponentsin itsapplications, hasallthenecessaryexpertisetocreateandim plementsafeguardswhichanticipatedangerou sconsequencesoffailures,monitorfailuresa ndtheirconsequences, , ,TI s goalis , FDAC lassIII(orsimilarlife-criticalmedicalequ ipment)