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power management sc5014 high efciency 4-channel hb led driver with i 2 c interface and phase-shifte d pwm dim ming revisionf2.0 features inputfvoltageff4.5vftof27vf outputfvoltageffupftof50v step-upf(boost)fcontroller ultra-fastftransientfresponsef(< 00s) programmablefswitchingffrequency linearfcurrentfsinks 4fstrings,fupftof 20ma/string currentfmatchingf %f currentfaccuracyf2%f pwmfdimming string-by-stringfphasefshifting inputfdimmingffrequencyf 00hz-30khz userfselectablef9forf 0-bitsfdimmingfresolution 5-bitsfanalogfdimming i 2 cfinterface faultfstatusffopen/shortfled,fuvlo,fotp devicefcontrol:fpllfsetting protectionffeatures open/shortedfled(s)fandfadjustablefovpf over-temperaturefandfuvlofshutdownfprotection 4mmfxf4mmf20-pinfqfnfpackage applications ultrabooks tm ,f all-in-onef pcs,f monitors,f automotive - displayfbacklighting backlightingfforfmid-sizefdisplays ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? description thefsc50 4fisfaf4-channel,fhighlyfintegrated,fhigh-ef - ciencyfstep-upf(boost)fhbfledfdriverfdesignedftofreducef thefthicknessfoffmid-sizeflcdfdisplays.fitffeaturesfafwidef inputfvoltagefrangef(4.5vftof27v),fphase-shiftedfpwmf dimming,fanalogfdimming,faffexiblefoutputfconfgura - tion,fanfi 2 cfinterface,fandfnumerousfprotectionffeatures.f thefsc50 4fexhibitsf2%ftof4%fhigherfefficiencyfwhenf usingfthefsamefsizefinductorsfasfexistingfledfdrivers.fbut,f unlikefexistingfdevices,fitfcanfalsofoperatefwithfinductorsf thatfarefupftof 0xfsmallerfwithoutfsacrifcingfefciency.f thisfpartfcanfalsofusefveryflow-proflefinductorsf(asfsmallf asf2.2h,f mmfheight),fwhichfallowsfledfdriversftofbef builtf directlyf intof thef lcdf panelf tof enablef ultra-thinf displays.f thefboostfcontroller,fwithfprogrammablefswitchingffre - quencyffromf200khzftof2.2mhz,fmaximizesfefciencyfbyf dynamicallyfminimizingfthefoutputfvoltagefwhilefmain - tainingfledfstringfcurrentfaccuracy.fitfprovidesfexcellentf linefandfloadfresponsefwithfnofexternalfcompensationf components.fanfexternalfresistorfadjustsfthefcurrentffromf 20- 20mafperfstring.fitfalsoffeaturesfpwmfdimmingfreso - lutionfoff9forf 0-bitsf(userfselectable)foverfafdimmingffre - quencyffromf 00hzftof20khz,fsynchronizedftofthefboostf oscillator.f string-by-stringf phasef shiftingf reducesf thef demandfonfthefinput/outputfcapacitance,fdecreasesfemi,f andfimprovesfdimmingflinearity. uvlo e - pad iset fset cpll scp sc 5014 r 3 r 6 flt c 3 ref flt vcc pgnd r 11 r 7 c 4 r 10 r 1 r 2 ovp io 4 r 9 r 8 v in = 4 . 5 to 27 v up to 120 ma / string io 1 io 2 io 3 c 5 r 5 pwmi pwmi sda scl for i 2 c en en l 1 q 1 r 4 ndrv cs d 1 v out up to 50 v v cc = 4 . 5 to 5 . 5 v typical application circuit
sc5014 2 pin confguration marking information ordering information device package sc50 4mltrt ()(2) mlpq-20f44 sc50 4evb evaluationfboard notes: ()f availablefinftapefandfreelfonly.ffafreelfcontainsf3,000fdevices. (2)f lead-freefpackagingfonly.ffdevicefisfweeefandfrohsfcompliant,f andfhalogenffree. agnd ovp 15 io 1 14 io 2 13 io 3 12 io 4 11 e n 20 c s 16 p g n d 17 18 v c c 19 uvlo 1 scp 2 ref 3 fset 4 cpll 5 p w m i 10 i s e t 8 f l t 9 s d a 7 s c l 6 n d r v 5014 yyww xxxxx xxxxx nnnn = part number yyww = date code xxxxx = semtech lot no. xxxxx = semtech lot no.
sc5014 3 exceedingfthefabovefspecifcationsfmayfresultfinfpermanentfdamageftofthefdeviceforfdevicefmalfunction.ffoperationfoutsidefoffthefparametersf specifedfinfthefelectricalfcharacteristicsfsectionfisfnotfrecommended. notes: ()f testedfaccordingftofjedecfstandardfjesd22-a 4-b. (2)ff calculatedffromfpackagefinfstillfair,fmountedftof3fxf4.5in,f4-layerffr4fpcbfwithfthermalfviasfunderfthefexposedfpadfperfjesd5 fstandards. absolute maximum ratings (refer to pgnd) vccfpinf(v)f f. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . f -0.3f tof +6.0 vin,fio ftofio4f(v) f. . . . . . . . . . . . . . . . . . . . . . . . . . f-0.3ffftofff+30 drvn,fovp,fcs,fen,fuvlo,fscp,fref,f flt f(v) f f. . f -0.3f tof +6.0 fset,fcpll,fscl,fsda,fiset,fpwmif(v)f f. . . . . . . f -0.3f tof +6.0 pgndftofagndf(v) f. . . . . . . . . . . . . . . . . . . . . . . . . f-0.3ffftofff+0.3 esdfprotectionflevel () f(kv)f f. . . . . . . . . . . . . . . . . . . . . . . . . . . . f2 recommended operating conditions ambientftemperaturefrangef(c) f. . . . . . . . f-40f < ft a f < f+85 vinf(v) f f. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . f 4.5f tof 27f io ftofio4fcurrentfperfstringff(ma)f f. . . . . . . . . . . ff 25f(max)f thermal information thermalfresistance,fjunctionftofambient (2)f (c/w)f f. . . . f 32 maximumfjunctionftemperaturef(c) f. . . . . . . . . . . . . . + 50 storageftemperaturefrangef(c) f. . . . . . . . . . . ff-65ftof+ 50 peakfirfrefowftemperaturef( 0sftof30s)f(c)f f. . . . . . +260 unlessfnotedfotherwise,ft a f=f25cfforftypical,f-40cf sc5014 4 parameter symbol conditions min typ max units boostfoscillatorffrequency f sw r fset f=f00k 0.85 .5 mhz boostfoscillatorffrequency f osc r fsetf varies 0.2 2.2 mhz maximumfdutyfcycle d max 88 92 % control signals: en, pwmi, sda, scl highfvoltagefthreshold v ih v cc ff=f4.5vftof5.5v 2. v lowfvoltagefthreshold v il v cc ff=f4.5vftof5.5v 0.8 v sdafoutputflow v sda(l) -6maffromfv cc ftofsda 0.3 v pinfleakagefcurrent i leak v en f=f0v,fffv pwmi f=ffv iset f=fv fset f=fv sda f=fv scl f=f5.0v - a pwm dimming input pwmifinputfdimmingffrequency f pwmi 00 30k hz pwmifinputfresolution 00hzf sc5014 5 electrical characteristics (continued) parameter symbol conditions min typ max units fault protection ledfshort-circuitfprotectionfthreshold v ion(scp) r 4f andfr 5f (3) 7xv scp 20xv scp 23xv scp v ledfopen-circuitfprotectionfthreshold v io_ocp 0.2 v ledfshort-circuitffaultfdelay t scp(delay) v ovpf setftof .5v,ff flt fgoesflow s flt fpinfleakagefcurrent i flt (leak) v en f=f0v,ffv flt f=ff5.0v - a flt foutputflow v flt (low) -5maffromf flt ftofv cc 0.3 v over-temperature protection thermalfshutdownftemperature t otp 50 c thermalfshutdownfhysteresis t otp-h 0 c i 2 c control interface: sda, scl timing specifcations sclfclockffrequency f scl 400 khz sclfclockflowfperiod t low(scl) .3 s sclfclockfhighfperiod t high(scl) 0.6 s holdftimefstartfcondition t hd(start) 0.6 s sdafsetupftime t su(sda) f 00 ns sdafholdftime t hd(sda) 0 0.9 s setupftimefstopfcondition t su(stop) 0.6 s busffreeftimefbetweenfstopf&fstart t bf .3 s notes: ()f ensuredfbyfdesignfandfcharacterization,fnotfproductionftested. (2) f ledfcurrentfmatchingfforf4fchannelsfisfdefinedfasftheflargestfofftheftwofnumbers,fi.e.,f(max-avg)/avgfandf(avg-min)/avg;fwherefmaxfisfthef maximumfledfchannelfcurrent,fminfisfthefminimumfledfchannelfcurrentfandfavgfisfthefaveragefoffthef4fledfchannelfcurrents. (3)f referftofthefapplicationfcircuitfonfpagef23,ffiguref2.
sc5014 6 typical characteristics v in (v) ???t??3????3 33??? ? ? ? ?? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? ? ? ? ? ?? ? ? ? ? ? ? ? ? ? ? ?? ? ? ? ? ? ? ? ? ? ? ?? ? ? ? ?? ? ? ? ? ?? ? ?? ???? backlight efficiency vs. input voltage 120ma/ch 60ma/ch backlight efciency vs. input voltage 10s4p ???t??3????3 33??? ???t??3????3 33??? ???t??3????3 33??? ???t??3????3 33??? ?? ???? ?? ? ?? ? ? ?? ? ??? ??? ??? ??? ? ?? ? ?? ???? ?? ? ?? ? ?? ???? ?? ? ?? ? ?? ???? ?? ?? ?? ?? ?? ??????? ??????? ??????? ??????? ??? ??? ??? ??? ????? ????? ????? ????? backlight efficiency vs. input voltage 10s4p 7s4p backlight efciency vs. input voltage 120ma/ch v in (v) led pwm dimming duty cycle (%) backlight efciency vs. led string current backlight efciency vs. led string current led pwm dimming duty cycle (%) pwm dimming linearity with phase shift pwm dimming linearity with phase shift led pwm dimming duty cycle (%) efciency(%) efciency(%) efciency(%) iout (ma) iout (ma) led pwm dimming duty cycle (%) pwm dimming linearity with phase shift ?33???3
?3????3????a?? ?33???3
?3????3????a?? ?33???3
?3????3????a?? ?33???3
?3????3????a?? ? ?? ? ? ?? ? ??? ??? ??? ??? ?? ?? ?? ?? ??? ??? ??? ??? ?? ?? ?? ?? ? ?? ? ?? ???? ?? ?? ???? ?? ? ?? ? ?? ???? ?? ??? ??? ??? ??? ??? ??? ??? ??? a??? a??? a??? a??? ?? ?? ?? ?? ?? ?? ?? ?? 60ma/ch, 10s4p, 20khz dimming pwm dimming linearity with phase shift ?33???3
?3????3??????a?? ?33???3
?3????3??????a?? ?33???3
?3????3??????a?? ?33???3
?3????3??????a?? ? ?? ? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ?? ?? ?? ?? ? ?? ? ?? ???? ?? ?? ???? ?? ? ?? ? ?? ???? ?? ??? ??? ??? ??? ??? ??? ??? ??? a??? a??? a??? a??? ?? ?? ?? ?? ?? ?? ?? ?? 120ma/ch, 10s4p, 20khz dimming ???t??3????3 33???3???? ???t??3????3 33???3???? ???t??3????3 33???3???? ???t??3????3 33???3???? ? ?? ? ?? ???? ?? ? ?? ? ? ?? ? ? ?? ? ?? ???? ?? ?? ???? ?? ? ?? ? ?? ???? ?? ??? ??? ??? ??? ??3?333????3??? ??3?333????3??? ??3?333????3??? ??3?333????3??? ??????? ??????? ??????? ??????? ?? ?? ?? ?? ???? ???? ???? ???? backlight efficiency vs. led string current 120ma/ch 60ma/ch efciency(%) ???t??3????3 33???3?? ???t??3????3 33???3?? ???t??3????3 33???3?? ???t??3????3 33???3?? ? ?? ? ?? ???? ?? ? ?? ? ? ?? ? ? ?? ? ?? ???? ?? ?? ???? ?? ? ?? ? ?? ???? ?? ??? ??? ??? ??? ??3?333????3??? ??3?333????3??? ??3?333????3??? ??3?333????3??? ??????? ??????? ??????? ??????? ?? ?? ?? ?? ???? ???? ???? ???? backlight efficiency vs. led string current 120ma/ch 60ma/ch v in =6v v in =12v
sc5014 7 temperature ( c) led string current matching vs. temperature led string current vs. r iset ?
??3???3 3???? ?
??3???3 3???? ?
??3???3 3???? ?
??3???3 3???? ? ?? ? ??? ??? ??? ??? ??? ??? ??? ??? ???? ???? ???? ???? ??? ??? ??? ??? ???? ???? ???? ???? ???? ???? ???? ???? ? ?? ? ?? ?? ?? ?? ??? ??? ??? ??? ?? ?? ?? ?? ?? ?? ?? ?? ?????t? ?????t? ?????t? ?????t? ??t? ? ??t? ? ??t? ? ??t? ? led string current vs. r iset r fset (k ) switching frequency vs. r fset idac register value (in decimal format) analog dimming 0 25 50 75 100 125 0 4 8 12 16 20 24 28 32 dec iled(ma) io1 led string current vs. analog dimming control register (idac) value led string current matching (%) boost switching frequency (khz) led string current (ma) typical characteristics (continued) led string current matching vs. temperature ?? ???? ?? ?? ???? ?? ?? ???? ?? ? ?? ? ?? ???? ?? ?? ???? ?? ?? ???? ?? ? ?? ? ?? ???? ?? ?? ???? ?? ? ?? ? ?? ???? ?? ??? ??? ??? ??? ??????:? ??????:? ??????:? ??????:? ??3?3??3?????? ??3?3??3?????? ??3?3??3?????? ??3?3??3?????? v cc =5v, 120ma/ch led string current vs. r iset ?
??3???3 3? ??? ? ?? ? ? ? ? ?? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? ? ? ? ? ?? ? ? ? ? ? ? ?? ? ? ? ? ? ? ? ? ? ? ?? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ??? ?t? ??? r iset (k ) led string current (ma) led string current accuracy vs temperature current accuracy vs. temperature a? a? a? a? ??? ??? ??? ??? ?? ?? ?? ?? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ?? ???? ?? ?? ???? ?? ? ?? ? ?? ???? ?? ?? ???? ?? ? ?? ? ?? ???? ?? ??? ??? ??? ??? ?????3?:? ?????3?:? ?????3?:? ?????3?:? ??3?3??3?????3?? ??3?3??3?????3?? ??3?3??3?????3?? ??3?3??3?????3?? temperature ( c) led string current accuracy (ma) v cc =5v, 120ma/ch time (20ms/div) vin start up testing condition: vin=12v,vcc=5v, leds=10s4p@120ma , rfset=100k , 25 : :: : iout vout vin sw vin start up v in 10v/div. v sw 20v/div. v out 20v/div. i out 300ma/div. 10s4p, 120ma/ch
sc5014 8 time (100ms/div) testing condition: vin=12v, 25 : :: : , leds=10s4p@120/ch , pwm indirect mode; pwm=10khz, pwmi on / off, duty=0% to 100% led current fade in/out (logarithmic) v_io4 iout vout pwmi led current fade in/out (logarithmic) line transient response led open circuit protection 100% dimming, 120ma/ch x 4 typical characteristics (continued) pwmi 5v/div. v io1 10v/div. v out 20v/div. i out 200ma/div. time (100ms/div) testing condition: vin=12v, 25 : :: : , leds=10s4p@120/ch , pwm indirect mode; pwm=10khz, pwmi on / off, duty=0% to 100% fade in/fade out (linear) v_io4 iout vout pwmi pwmi 5v/div. v io1 10v/div. v out 20v/div. i out 200ma/div. led current fade in/out (linear) time (4us/div) test condition: 8vin to 20vin, 10s4p@120ma per stri ng, rfset=100k , vin rt=1us line transient response v_io4 il vout pwmi v in 10v/div. v out 1v/div. v io1 1v/div. il 3a/div. time (20ms/div) leds open-circuit protection testing condition: vin=12v, 25 : :: : , leds=10s4p@120ma/ch, ch4 open, rfset=100khz, rovp2=357k en iout vout flt v en 5v/div. flt 5v/div. v out 20v/div. i out 200ma/div. starting with one led string open-circuit load transient response load transient response pwmi(10khz)=2% to 98%, vin=12v, 120ma/ch x 4 fading disabled time (100us/div) load transient response testing condition: vin=12v, 25 : :: : , leds=10s4p@120ma/ch, rfset=100khz, pwmi=10k, duty=2% to 98% iout vout pwmi pwmi 5v/div. v out 200mv/div. i out 200ma/div. time (100ms/div) load transient response testing condition: vin=12v, 25 : :: : , leds=10s4p@120ma/ch, rfset=100khz, pwmi=10k, duty=98% to 2% iout vout pwmi 8v 20v pwmi(10khz)=98% to 2%, vin=12v, 120ma/ch x 4 fading disabled pwmi 5v/div. v out 200mv/div. i out 200ma/div.
sc5014 9 time (2ms/div) led dimming without phase shift testing condition: vin=12v, 25 : :: : , leds=10s4p@120ma/ch, rfset=100khz, pwmi=200hz, duty=10% il v_io1 v_io2 iout led dimming without phase shift led dimming without phase shift led dimming with phase shift 35% dimming@200hz, v in =12v, 4p10s, 120ma/ch typical characteristics (continued) v io1 10v/div. v io2 10v/div. i l 1a/div. i out 400ma/div. led dimming with phase shift testing condition: vin=12v, 25 : :: : , leds=10s4p@120ma/ch, rfset=100khz, pwmi=200hz, duty=10% il v_io1 v_io2 iout led dimming with phase shift led dimming without phase shift testing condition: vin=12v, 25 : :: : , leds=10s4p@120ma/ch, rfset=100khz, pwmi=200hz, duty=35% il v_io1 v_io2 iout led dimming with phase shift testing condition: vin=12v, 25 : :: : , leds=10s4p@120ma/ch, rfset=100khz, pwmi=200hz, duty=35% il v_io1 v_io2 iout 35% dimming@200hz, v in =12v, 4p10s, 120ma/ch time (40us/div) analog dimming transient via i 2 c testing condition: vin=12v, 25 : :: : , leds=10s4p@120ma/ch, rfset=100khz, 60ma/ch to 120ma/ch iout vout sda sw v sw 20v/div. i out 300ma/div. analog dimming transient via i 2 c testing condition: vin=12v, 25 : :: : , leds=10s4p@120ma/ch, rfset=100khz, 120ma/ch to 60ma/ch iout vout sda sw time (2ms/div) v io1 10v/div. v io2 10v/div. i l 1a/div. i out 400ma/div. 10% dimming@200hz, v in =12v, 4p10s, 120ma/ch 10% dimming@200hz, v in =12v, 4p10s, 120ma/ch time (2ms/div) v io1 10v/div. v io2 10v/div. i l 1a/div. i out 400ma/div. time (2ms/div) v io1 10v/div. v io2 10v/div. i l 1a/div. i out 400ma/div. analog dimming transient via i 2 c analog dimming transient via i 2 c 60ma/ch to 120ma/ch 120ma/ch to 60ma/ch v sda 5v/div. v out 2v/div. time (40us/div) v sw 20v/div. i out 300ma/div. v sda 5v/div. v out 2v/div.
sc5014 0 pin descriptions pin # (qfn) pin name pin function uvlo inputfunder-voltageflockoutfpinffdevicefisfdisabledfwhenfthisfpinfisflessfthanf .23vf(nominal).ffaddfafresistorf dividerffromfthisfpinftofthefinputfvoltagefandfagnd,frespectively. 2 scp short-circuitfledfprotectionfprogrammingfpinffshortedfledfprotectionfdisablesfthefindividualfchannelfwhenfthef currentfsinkfvoltagefexceedsfthefprogrammedfvoltagefthreshold.ffaddingfafresistorfdividerffromfthisfpinftofreffandf pgndfprogramsfthefshorted-ledfprotectionfupftof20xfthefv scp fvoltage.ffpullingfthefpinfhighftofvccfdisablesfthefscpf featurefonfallfchannels. 3 ref .23vfreferencefvoltagefoutputfpinffconnectfaf ffceramicfbypassfcapacitorffromfthisfpinftofground. 4 fset step-upf(boost)ffrequencyfsetfpinffconnectfafresistorffromfthisfpinftofgroundftofsetftheffrequencyffromf200khzftof 2.2mhz. 5 cpll compensationfforfthefinternalfpllffconnectfafcompensationfresistorfandfcapacitorffromfthisfpinftofground.fthisf pinfcanfbefleftffoatingfiffnotfused. 6 scl i 2 cfserialfclockfinputffthisfpinfmustfbefconnectedftofgroundfiffnotfused. 7 sda i 2 cfserialfdatafinputffthisfpinfmustfbefconnectedftofgroundfiffnotfused. 8 iset ledfcurrentfprogrammingfpinffconnectfanfexternalfresistorftofgroundftofprogramfthefcurrentfinfthefledfstrings.f forfmorefdetailsfpleasefreferftofledfstringfpeakfcurrentfprogrammingfon fpagef3. 9 flt logicflowffaultfstatusfpinffopen-drainfoutputfisflatchedflowfwhenffaultfconditionfisfdetected:fopen/shortfled,f shortedfstring,fovpforfotp.ffffaultfstatusfcanfbefresetfbyfremovingffaultfcondition(s)fandftogglingfthefen,fvccforf uvlofpins.fthisfpinfcanfbefleftffoatingfiffnotfused. 0 pwmi ledfstringfpwmfdimmingfcontrolfinput. f~4 io4f~fio regulatedfcurrentfsinkfledfchannelf4ftofchannelf frespectivelyffconnectfthefrelatedfiofpinftofthefcathodefoff thefbottomfledfinfstringf4ftofstringf frespectively.fconnectfthefrelatedfiofpinftofgroundftofdisablefthefrelatedfledf stringfduringfpowerfon. 5 ovp over-voltageffeedbackfpinffover-voltagefactivatedfwhenfpinfvoltagefexceedsf .2v.ffusefafresistorfdividerftiedftof thefoutputfandfgndftofsetfthefovpflevel. 6 cs step-upf(boost)fswitchfcurrentfsensefpinffconnectfafresistorffromfthisfpinftofgroundffforfcurrentfsensef-futilizedfinf peakfcurrentfmodefcontrolfloopfandfover-currentfsensefcircuitry. 7 pgnd powerfgroundfftiefthisfpinftofthefpowerfgroundfplanefcloseftofinputfandfoutputfdecouplingfcapacitors. 8 ndrv gatefdriveffforfthefexternalfstep-upf(boost)fn-channelfmosfet. 9 vcc inputfbiasfvoltagefsupplyfforftheficffacceptsf4.5-5.5vfinputs.ffaddfaf fforflargerfceramicfbypassfcapacitorffromf thisfpinftofground. 20 en logicfhighfenablefpinffpullflogicfhighftofenablefthefdeviceforfpullflowftofdisablefandfmaintainflowfshutdownf current. - pad agndfthermalfpadfforfheatsinkingfpurposesffitfshouldfbefconnectedftofgroundfplanefforfproperfcircuitfoperation.
sc5014 block diagram duty cycle mux iset ea minimum voltage detection otp ndrv ls 4 io 1 io 2 io 3 ovp en pwmi cpll vcc cp vco led open / short fault sda scl pwm dim adjust otp 8 fset i 2 c interface cs iset adjust 1 / n pll i - ref adj led freq adjust i 2 c ( pll range ) pwm freq . adjust 18 5 - bit dac uvlo boost oscillator vbg scp ref x 20 sc _ ref duty cycle extractor recycle generator i 2 c interface and led control logic control logic flt oc / sc detection sc _ ref io 4 comp 10 5 4 osc clim + + - pwm comp slope comp 10 mhz ( system clk ) pgnd 10 4 4 dc dc bg ilim + - + - ovp + -
sc5014 2 general description thefsc50 4fcontainsfafhighffrequency,fcurrent-mode,f internallyfcompensatedfboostfcontrollerfwithf4fconstantf currentfsinksfforfdrivingfledfstrings.ffthefledfcurrentfforf allfstringsfisfprogrammedfbyfanfexternalfresistor.fthefboostf converterfoperatesftofmaintainfminimalfrequiredfoutputf voltagefforfregulatingfthefledfcurrentftofthefprogrammedf value.ffaftypicalfbacklightfapplicationfusesf3ftof 4fledsf perfeachfstring,fwithfcurrentfdrivenfupftof 20ma. fthef uniquefcontrolfloopfoffthefsc50 4fallowsffastftransientff responsefinfdealingfwithflinefandfloadfdisturbances. thef sc50 4,foperatingfwithfanfexternalfpowerfmosfet,fregu - latesfthefboostfconverterfoutputfvoltagefbasedfonfthef instantaneousfrequirementfoffthef4fstringfcurrentfsources.f thisfprovidesfpowerftofthefentireflightingfsubsystemfwithf increasedfefciencyfandfreducedfcomponentfcount.ffitf supportsfpwmfdimmingffrequenciesffromf 00hzftof30khzf andfthefsupplyfcurrentfisfreducedftof2maftypicalffwhenfallf ledfstringsfarefof.ff start-up whenfthefenfpinfisfpulledfupfhighf(>2. v),fthefdevicefisf enabledfandfthefuvlofandfvccfpinfvoltagesfarefchecked.f thefvccfvoltagefhasffxedfunder-voltagefrisingfandffallingf tripfpoints.fiffthefvccfpinfisfhigherfthanf4.2vfandfthefuvlof pinfvoltagefisfgreaterfthanf .23v,fthefsc50 4fgoesfintofaf start-upfsequence.fthefuvlofpinfvoltagefcanfbefusedftof programf thef inputf powerf sourcef voltagefvinf turn-onf thresholdfandfitsfhysteresisf(referftofthefdetailedfapplica - tionfcircuitfonfpagef23,ffiguref2)fasfshownfbyftheffollow - ingfequations: f v in_turnon f[v]f=f .23fxf(r f +fr 2 )f/fr f v in_hysteresis f[v]f=f 0 -5 fxfr 2f [] infthefnextfphase,fthefsc50 4fchecksfeachfiofpinftofdeter - minefiffthefrespectivefledfstringfisfenabled.feachfiofpinfisf pulledfupfwithfaf 00 a fcurrentfsource.fiffanyfiofpinfisfcon - nectedftofground,fitfwillfbefdetectedfasfanfunusedfstring,f andfwillfbefturnedfof.fthisfunusedfstringfcheckingfproce - dureftypicallyftakesf ms.fafterfthis,fthefsc50 4fentersfintof afsoft-startfsequence. thefsoft-startffunctionfhelpsftofpreventfexcessfinrushf currentfthroughfthefinputfrailfduringfstart-up.finfthef sc50 4,fthefsoft-startfisfimplementedfbyfslowlyframpingf upfthefreferencefvoltageffedftoftheferrorfamplifer.fthisf closedfloopfstart-upfmethodfallowsfthefoutputfvoltagef toframpfupfwithoutfanyfovershoot.fthefdurationfoffthef soft-startfinfthefsc50 4fisfcontrolledfbyfanfinternalftimingf circuit,fwhichfisfusedfduringfstart-upfandfisfbasedfonfthef boostfconverterfswitchingffrequency.fforfexample,fwithf switchingf frequencyf atf mhz,f itf isf 8msf typicalf andf becomesf4msftypicalfwhenfthefswitchingffrequencyfisf 2mhz.ff iffthefpwmfvoltagefgoesflowfwhilefthefsc50 4fisfinfsoft - startfoperation,fthefsc50 4fswitchesftofstandbyfmode,f wherefthefexternalfpowerfmosfetfandfthefledfcurrentf sourcesfwillfbefturnedfoffimmediately.fthefinternalfsoft- startftimerfisfturnedfoffandfthefsoft-startfvaluefisfsaved.f whenfthefpwmfvoltagefgoesfhi ghfagain,fthefsoft-startf resumesffromfthefpreviouslyfsavedfvalue. eachfledfcurrentfsourcef(io ftofio4)ftriesftofregulatefthef ledfcurrentftofitsfsetfpoint.fthefcontrolfloopfwillfregulatef thefoutputfvoltagefsuchfthatfallfthefiofpinfvoltagesfarefatf leastf0.9vftypical. shutdown whenfthefenfpinfisfpulledfdownfbelowf0.8v,fthefdevicef entersfintofshutdownfmode.finfthisfmode,fallfthefinternalf circuitryfisfturnedfoffandfthefsupplyfcurrentfisflessfthanf af(max).f infthefscenariofwherefthefenfpinfvoltagefisfhigh,fbutfvccf voltageffallsfbelowfthefrespectivefuvlofthreshold,fthef sc50 4fgoesfintofafsuspendfmode.finfthisfmode,fallfthef internalfcircuitryfexceptfthefreferencefandfthefoscillatorf arefturnedfof. thermal shutdown (tsd) iffthefthermalfshutdownftemperaturefofftypicalf 50cfisf reached,fthefboostfconverterfandfallfiofcurrentfsourcesf arefturnedfof.fthef flt fpinfisfforcedflowfinfthisfcondition.ff whenftheftemperatureffallsfbelowftheftsdftripfpointfbyf 0c,f thef sc50 4f willf restartf followingf thef start-upf sequencefasfdescribedfbefore.fthef flt fpinfisflatchedffandf willfstayflow,fitfisfresetfbyfcyclingfthefen,fvccforfuvlo.f applications information
sc5014 3 applications information (continued) boost converter operation thefsc50 4fincludesfafboostfcontrollerfwithfprogramma - blefswitchingffrequency.fitfappliesfafcurrent-modefcontrolf methodfwithfanfintegratedfcompensationfloopfasfshownf infthefdiagramfbelow.fthefclockf(seefblockfdiagramfonf page )ffromfthefoscillatorfsetsftheflatchfandfturnsfonfthef externalfpowerfmosfet,fwhichfservesfasfthefmainfpowerf switch.fthefcurrentffowingfthroughfthisfswitchfisfsensedf byfthefcurrentfsensefresistorfinfseriesfwithfthefswitch.fthef sensedfswitchfcurrentfisfsummedfwithfthefslope-com - pensatedframpfandffedfintofthefmodulatingfinputfoffthef pwmfcomparator.fwhenfthefmodulatingframpfintersectsf theferrorfampliferfoutputf(comp),ftheflatchfisfresetfandf thefpowerfmosfetfisfturnedfof.ffthefsensefresistorfalsof setsfthefpeakfcurrentflimitfoffthefpowerfmosfet,fi ocp fusingf theffollowingfequation: f i ocp [a]f=f0.4f/fr csf [] ea min . voltage detection boost oscillator control logic comp osc + + - pwm comp slope comp dc + - v in = 4 . 5 to 27 v io c 5 l 1 q 1 d 1 ls cs ndrv r cs thefcurrent-modefcontrolfsystemfcontainsftwofloops.fforf thefinnerfcurrentfloop,ftheferrorfamplifierf(ea)foutputf (comp)fcontrolsfthefpeakfinductorfcurrent.finfthefouterf loop,fthefeafregulatesfthefoutputfvoltagefforfdrivingfthef ledfstrings.f boost converter switching frequency selection thefresistorfbetweenffsetfandfgndfsetsfthefboostfcon - verterfswitchingffrequencyf(200khzftof2.2mhz)fusingfthef followingfequation: f f sw f[khz]f=f 0 5 /fr fsetff [k] afhigherfswitchingffrequencyfallowsfthefusefofflow-proflef heightfinductorsfforfspace-constrainedfandfcost-sensitivef applications.ff over-voltage protection (ovp) thefsc50 4fffeaturesfprogrammablefoutputfover-voltagef protectionftofpreventfdamageftoftheficfandfoutputfcapaci - torfinfthefeventfoffafledfstringfopen-circuit.fthefboostfcon - verterfoutputfvoltagefisfsensedfatfthefovpfpinfthroughffthef resistorfvoltagefdivider.fthefovpftripfthresholdf(referftof detailedfapplicationfcircuitfonfpagef23,ffiguref2)fcanfbefcal - culatedfusingftheffollowingfequation: f ovpftripfvoltagef[v]f=f .2fxf(r f+fr 2 )f/fr 2 whenfthefovpfpinfvoltagefexceedsf .2v,fthefboostfcon - verterfturnsfoffandfthef flt fpinfisfpulledflow.fwhenfthef ovpfpinfvoltageffallsfbelowfthefovpfthresholdf(falling),f thefboostfconverterfrestartsfandfthef flt fpinfisfreleased.f therefisf 0mvfhysteresisfbetweenfthefovpfpinfthresholdf (falling)fandfthefovpfpinfthresholdf(rising).fthisfresultsfinf anfoutputfvoltagefhysteresisfexpressedfas:f ffffffoutputfovpfhysteresisf[mv]f=f 0fxf(r f +fr 2 )f/fr 2 led current sink thefsc50 4fprovidesf4fcurrentfsinksfandfeachfcanfsinkfupf tof 20mafcurrent.ffitfincorporatesfledfstringfshort-circuitf protectionf(trip-levelfprogrammable;fcanfbefdisabled)f andfledfstringfopen-circuitfprotection. led string peak current programming ledfstringfpeakfcurrentf(atf 00%fdimming)fcanfbefsetfbyf selectingfresistorfr iset ,ffconnectedfbetweenfisetfandfgnd.f thefrelationshipfbetweenfr iset fresistancefandfsinglefledf stringf peakf currentf isf calculatedf usingf thef followingf equation: f i led f[ma]f=f2fxf( 036fxf.23)f/fr isetf [k]f thefstringfcurrentfcanfbefprogrammedfupftof 20ma. unused strings thefsc50 4fmayfbefoperatedfwithflessfthanf4fstrings.ffinf thisfmodefoffoperation,fallfunusedfiofpinsfshouldfbefcon - nectedftofground.fduringfstart-up,fthesefunusedfstringsf arefdetectedfandfdisabledfwhilefotherfactivefstringsfworkf normally,fandf flt fdoesfnotf getf pulledflow.
sc5014 4 led short-circuit protection (scp) thefsc50 4ffeaturesfafprogrammablefledfshort-circuitf protectionf(scp).fthisfallowsfthefpartftofbefcustomizedf basedfonftheffledfforwardfvoltagef(v f )fmismatchesfbetweenf thefledfstrings.fiffoneforfmorefledsfarefdetectedfasfshort- circuited,fthefcorrespondingfstringfwillfbeflatchedfof.ffthef voltagesfonfallfiofpinsfarefmonitoredftofcheckfiffanyfiofpinf exceedsfthefscpftripfpoint.fthefiofvoltagefforfledfstring(s)f withffaultyfshort-circuitfled(s)fwillfbefhigherfthanfotherf normalfiofpinfvoltages.ffthisfledfshort-circuitfprotectionf tripf levelf (seef detailedf applicationf circuitf onf pagef 23,ffff figuref2)fisfexpressedfbyftheffollowingfequation: f v scp_trip f[v]f=f20fxf( .23fxfr 4 )f/f(r 4 f+fr 5 ) iffanyfiofpinfvoltagefexceedsftheftripfvoltage,fthefiofcurrentf sinkfwillfbeflatchedfoffandfthef flt fwillfgoflow.fthisflatchfcanf befresetfbyfcyclingfuvlo,fvccforfen.fotherfledfstringsfaref unafectedfandfcontinuefinfnormalfoperation.fthisfprotec - tionfwillfbefdisabledfiffscpfisftiedftofvcc.f therefisfaftypicalf 0sfscpfdetectionftime fin fpwmfdimmingf applications.fiffthefpwmfdimmingfon-timefisflessfthanfthef scpfdetectionftime,fthefscpfcannotfbefenabled. infmanyfapplications,fledfstringsfarefconnectedftofthefiof pinsfthroughfafmechanicalfconnector,fwhichfcannotfsupportff anfelectricalfconnectionfatfspecifcftimes.fthisfconnectionf applications information (continued) mightf causef noisef onf thef iof pins.f iff thisf noisef isf largef enough,fitfmayftriggerfaffalsefscpfmode.funderfsuchfcondi - tion,f af ceramicf decouplingf capacitorf ( 00pff ~f 8.2nf)f betweenfiofpinftofgroundfcanfhelpfpreventfthefsc50 4f fromfenteringfthefprotectionfmodefbyffalseftrigger.for,f simplyfdisablefthisffeaturefbyfconnectingfscpfpinftofvccf pin. led open-circuit protection iffanyfledfstringfbecomesfopen,fthefrespectivefiofpinf voltagefwillfbefpulledftofground.fconsequently,fthefinter - nalfcompfnodef(outputfofferrorfamplifer)fisfdrivenfhigh,f whichfcausesfthefboostfoutputfvoltageftofincrease.fthef outputfvoltagefwillfbefeventuallyfclampedftofafvoltagef setfbyfthefovpfresistorfdivider.funderfthisfcondition,fthef faultyfstringfisflatchedfoffandfthef flt fpinfisfpulledflow.f thefboostfvoltagefgetsfregulatedftofthefvoltagefrequiredf tofsetfallfnon-faultyfiofpinsfabovef0.9vf(typ).fthefremain - ingfstringsfremainfinfnormalfoperation.fthef flt fandfthef fault-outfledfcurrentfsinkflatch-offcanfbefresetfbyfcyclingf uvlo,fvccforfen. led analog dimming control thefledfcurrentfinfsc50 4fcanfbefdimmedfviafthef5-bitf analogfdimmingfregisterf(registerfaddress:f0x02).fthefledf currentfcanfbefadjustedfinf32fstepsffromf0maftofmaximumf value,fwhichfisfdeterminedfbyfthefr iset fresistor. soft - start 1 i 2 c interface 1 0 int _ duty bit d [ 9 : 0 ] bits 10 pwm generator freq bits 10 phase shifting fastfreq bit ph _ shift bit 8 en 1 0 pwm input 4 int _ pwm bit extracted duty cycle from pwmi input led frequency and phase - shifter block pwm _ ps [ 4 : 1 ] all bits identical when phase shifting disabled 4 pwm [ 4 : 1 ] 10 duty cycle extractor pwm input figure 1 led pwm dimming control
sc5014 5 applications information (continued) thefsc50 4fhasfafuniquefdacfarchitecturefwhichfallowsfitf tofhavefexcellentfledfcurrentfaccuracyfandfstring-to-stringf matchingfoverfthefentirefdacfrange.f thefanalogfdimmingfmethodfcanfbefusedfinfconjunctionf withfpwmfdimmingftofincreasefthefdimmingfresolution. f thef fastf loopf responsef off thef sc50 4f allowsf thef ledf currentftoftransitionftofafnewfvaluefwithinf 60sforfso.f pleasefreferftofthefgraphsfinftheftypicalfcharacteristicsf section. led pwm dimming control thef sc50 4f supportsf threef pwmf dimmingf modesf forf controllingfthefbrightnessfoffthefleds.f thefdimmingfmodesfare:f ( )fpwmfdirect,f (2)fpwmfindirectfandf (3)fi 2 cfcontrol itfprovidesfflexibilityfinfsettingfthefdutyfcyclefandffre - quencyfoffthefledfpwmfsignal.fthefpwmfdimmingfmodef isfsetfthroughfthefdevicefcontrolfregisterf(registerfaddress:f 0x0)fdcrf[ :0]fbits.freferftoftablef fforfmorefdetails. (1) pwm direct control thefpwmfinputfneedsftofbefheldfhighfforfnormalfopera - tion.ffpwmfdimmingfcanfbefachievedfbyfcyclingfthefpwmf inputfatfafgivenffrequencyfwherefaflowfonfthefpwmf inputfturnsfoffallfiofcurrentfsinksfandfafhighfturnsfonfallf iofcurrentfsinks.ffthefpwmfpinfcanfbeftoggledfbyfexternalf circuitryftofallowfpwmfdimming.ffinfaftypicalfapplication,f afmicrocontrollerfsetsfafregisterforfcounterfthatfvariesfthef pulsefwidthfonfafgpiofpin.ffthefsc50 4fallowsfdimmingf overfafwideffrequencyfrangef( 00hz-30khz)finforderftof allowfcompatibilityfwithfafwidefrangefoffdevices.fthisf includesfthefnewestfdimmingfstrategiesfthatfavoidfthef audiofbandfbyfusingfhighffrequencyfpwmfdimming.finf thisfmanner,fafwidefrangefoffilluminationfcanfbefgener - atedf whilefkeepingfthefinstantaneousfledfcurrentfatfitsf peakfvaluefforfhighfefciencyfandfcolorftemperature.ffthef sc50 4fprovidesfaf 000: fdimmingfrangefatf khzfpwmf frequency.fthefledfcurrentfsinksfturnfon/offveryfrapidlyf (<25ns,ftypical).ffthisfallowsfafwidefdimmingfratio.fanfaddi - tionalfadvantagefoffpwmfdimmingfisfthatfitfavoidsfin-rushf currentsfwhenffllingfthefboostfoutputfcapacitor.fsimplyf applyfthefpwmfsignalftofthefdevicefatf 0%fdutyfforfafmilli - secondf orf two,f andf in-rushf currentf isf reduced.f f thisf dimmingftimefwillfvaryfbasedfonfthefnumberfoffledsfandf thefsizefoffthefoutputfcapacitor.fthisfcanfbefeasilyfdeter - minedfduringftestingfandfprogrammedfintofthefmicrocon - trollerffrmware. table 1 led dimming control methods pwm dim - ming mode register settings dcr[1:0] pwm input source led pwm output phase shift option pwm frequency pwm duty cycle pwmfdirectf control 00 pwmifpinf input samefasfthefpwmifinput f (rangef 00fhzftof30khz) samefasfthefpwmifinput no pwmfindirectf control (default option) 0 pwmifpinf input setfviaftheffreqfregisterf f (0x05)fandffast_freqfbit 0khzf(max):ffast_freq=0 20khzf(max):ffast_freq= samefasfthefdutyfcyclefoffthefpwmfinput yes i 2 c f control i 2 c f control setfviaftheffreqfregisterf f (0x05)fandffast_freqfbit 0khzf(max):ffast_freq=0 20khzf(max):ffast_freq= setfviafthefdutyfcyclefcontrolf f registerf(0x03,f0x04) 0-bitsf@f 0khzfoutput 9-bitsf@f20khzfoutput yes
sc5014 6 applications information (continued) (2) pwm indirect control thisfisfthefdefaultfmodefforfledfpwmfdimmingfinfthef sc50 4.finfthisfmode,fthefinputfsignalfappliedfonfthefpwmf pinfisfpassedfthroughfafdutyfcyclefextractorfblockfafterfthef systemfhasfdetectedftwofsuccessivefdutyfcyclesfthatfarefthef same.fthefextractorfmeasuresfthefdutyfcyclefoffthefpwmf input,fand,fdependingfonfthefvaluefofffast_freq,fthefdutyf cyclefisfconvertedftofaf9-bitfvaluef(fast_freqf=f )forfaf 0- bitfvaluef(fast_freqf=f0).fthisfvaluefisfthenfpassedftofthef pwmfgeneratorfblockfasfshownfinffiguref . thefledfpwmfoutputffrequencyfisfsetfviaftheffreqfregis - terf(addressf0x05)fandftheffast_freqfbit. withffast_freqf=f0,flowfdimmingffrequencyfoptionfisf selectedfandfthefpwmfdimmingffrequencyfwillfbefaccord - ingftoftheffollowingfequation: 10khz(max) ]1 ]0 : 7[ freq [ 1024 mhz 10 frequency dimming pwm = + = withffast_freqf=f , fthefh ighfdimmingffrequencyfoptionf isfselectedfandfthefpwmfdimmingffrequencyfisfshownfbyf theffollowingfequation: 20khz(max) ]1 ]0 : 7[ freq [ 512 mhz 10 frequency dimming pwm = + = the fdefaultfoptionfisffast_freqf=f .fthisfgivesf9-bitfdutyf cyclef resolutionf andf upf tof 20khzf dimmingf frequencyf range.fthefpwmfinputfisfusuallyfgeneratedfbyfthefsystemf graphicsfprocessor.fthisfmodefallowsfthefuserftofsetfthef pwmf outputf dimmingf frequencyf independentf off thef pwmifinput. iffthefpwmfsignalfhasfjitter,fthefsc50 4fprovidesfanfoptionf tofflterfitfout.fhysteresisfisfalsofprovidedfbyfselectingfthef wnd[ :0]fbitsfinfthefdcrfregisterf(addressf0x0 ).fwnd[ :0]f bitsfsetfthefwindowfcomparatorfsuchfthatfiffafchangefinf thefdutyfcyclefisfdetectedfwhichfisfsmallerfthanfthefsetf window,fthenfitfisfignored. (3) i 2 c control infi 2 cfdimmingfmodef(referftoffiguref ,fpagef 4),fbothfthef outputfledfdimmingfdutyfcyclefandfthefdimmingffre - quencyfarefsetfviafthefinternalfregisters.fthefpwmifpinf shouldfbefconnectedftofground.finfthisfmode,fthefledf dimmingf dutyf cyclef isf setf viaf thef dutyf cyclef registersf (addressesf0x03,f0x04);fandfthefdimmingffrequencyfisfsetf viaftheffreqfregisterf(addressf0x05)fandftheffast_freqf bit. withffast_freqf=f0,fthefledfdutyfcyclefcanfachievef 0-bitf resolution,fd[9:0],fwhichfisfcombinedfbyftwofportions:f( )f msbfportionf-fregisterfaddressf0x03f[ :0]fandf(2)flsbfportionf -fregisterfaddressf0x04f[7:0]fasfshownfbelow.f thefdimmingfdutyfcyclefwithffast_freqf=f0fcanfbefcalcu - latedfas: f ledfdimmingfdutyfcyclef=f{d[9:0] decimalf }/2 0 - withffast_freqf=f ,fthefledfdutyfcyclefcanfachievef9-bitf resolution,fd[9: ],fwhichfisfcombinedfbyftwofportions:f( )f msbfportionf-fregisterfaddressf0x03f[ :0]fandf(2)flsbfportionf -fregisterfaddressf0x04f[7: ]fasfshownfbelow. thefdimmingfdutyfcyclefwithffast_freqf=f fcanfbefcalcu - latedfas: f ledfdimmingfdutyfcyclef=f{d[9: ] decimalf }/2 9 - infbothfcasesfmentionedfabove,fthefdutyfcyclefisffxedftofbef 0fwhenfd[9:0]fisfsetfasf0x00. thefpwmfdimmingffrequencyfisfcontrolledfthefsamefwayfasf infindirectfcontrol. f
sc5014 7 phase-shift pwm dimming thefsc50 4fprovidesfanfoptionfforfphase-shiftedfledfpwmf dimming.fthisfoptionfisfavailablefinfbothfpwmifindirectf controlfandfi 2 cfcontrol.fthefphase-shiftfoptionfisfsetfbyftheffff ph_shiftfbitfinfthefdevicefcontrolfregisterf(registerfaddressf 0x0 ).fthisfoptionfdelaysfthefturn-onfoffthefledfstringsf basedf onf thef numberf off thef stringsf inf operationf (thef numberfoffthefstringsfinfoperationfisfdeterminedfduringf thefstart-up).ffthefdelayftimefcanfbefcalculatedfbyfthefffffffff followingfequation: frequency dimming pwm led f operation in strings of number n , n f t pwm pwm phase , , , f 1 f phase-shiftfmodefisfdisabledfduring fthefs oft-startfperiod.f thisfallowsfthefoutputftoframpfupftofthefcorrectfvoltagefinf afcontrolledffashion. phase-shiftin gfreducesfthefpeakfinputfcurrent,fdecreasesf emifandfimprovesfthefdimmingflinearity.ftheffguresfinfthef typicalf characteristicsf sectionf onf pagef 6f showf thef improvementfinfdimmingflinearityfwithfphase-shiftedf versusfnon-phase-shiftedfdimming. backlight fade-in and fade-out options thefsc50 4ffeaturesfanfoptionfforffade-infandffade-outf brightnessfcontrol,fwhichfallowsfafsmoothftransitionffromf onefbrightnessflevelftofanother. registersf associatedf withf thesef fadingf functionsf aref shownfinfthisfsection. fadef optionf (registerf addressf 0x09)f f setsf fadef enablefoptions,ffadeftime,ffadeftype. fadef ratef (registerf addressf 0x0a)f f setsf fadef stepf sizefoption. theffadefoptionfregisterfallowsfthefuserftofselectffading,f choosefbetweenflinearforflogarithmicffading,fandftofsetf theffadingftime.fthefdefaultfsettingfisffadingfenabledfwithf logarithmicfmode.ftheffadingftimefisfdeterminedfbyfthef ledfpwmfdimmingffrequency.ftheffadefsettingfisfshownf inftablef2. . 2. anfexamplefforfcalculatingftheffadingftimefisfshownfinf thisfsection.fassumingfledfpwmfdimmingffrequencyfisf 0khz,f thenf 0-bitsf aref assignedf forf 024f dutyf cyclef settings.f tablef2fffadefsetting dutyf cyclef zone dutyfcyclef range stepf increment stepf interval totalfstepsf withinfthef range 0ftof5 2 52 2 5 2ftof767 256 3 768ftof 024 2 256 thef timef requiredf tof gof fromf 0%f ( 02/ 024)f tof 90%f (922/ 024)fdutyfcyclefcanfbefcalculatedffusingftheffollow - ingfequation: t pwm f=f00fsf(withf 0khzfdimmingffrequency) cyclefinfzonef# f=f(5 f-fstartingfdutyfcycle)fxf[(zonef#f stepfinterval)f/f(zonef# fstepfincrement)]f cyclefinfzonef#2f=ftotalfstepsfinfzonef#2fxf[(zonef#2fstepf interval)f/f(zonef#2fstepfincrement)] cyclefinfzonef#3f=f(endfdutyfcyclef-f768)fxf[(zonef#3fstepf interval)f/f(zonef#3fstepfincrement)]f infthisfcase,ftheftotalfcyclefwillfbe: totalfcyclef=f2fxf(5 -02)f+ffxf256f+f0.5fxf(922f-f768)f f ffffff=f5 totalffadingftimef=ftotalfcyclefxf t pwm f f fffff=f5fxf 00fsf=f5.ms timef requiredf tof gof fromf 0%f ( 02/ 024)f tof 90%f (922/ 024)fdutyfcyclefcanfbefcalculatedffusingftheffollow - ingfequation: ms 115.1 t 1151 time total ) ( ) ( cycle total period) dimming (pwm s 100 t pwm pwm s r r s 1151 768 922 2 1 256 102 511 2 applications information (continued)
sc5014 8 table 3 fault protection descriptions type of fault user disable? fault criteria action on fault recovery device flt pin (latching / non-latching condition(s) flt pin inputf under-voltagef atfvin f (uvlo) no v in ff.23vf f (rising) high no v in ff.23vf f (rising) high inputf f under-volt - agefatfvccf f (uvlo) no vccff4.2v f (rising) high no vccff4.2v f (rising) high over-voltagef protectionf (ovp) no v ovp f>f.23v f (rising) regulateftofovpf threshold: f i o(n) f=fon low f (non-latching) v ovp ff0.4v limitfq ffetfdrainf currentff0.4v high shortedf led(s) yes,ftief scpftof vcc v io(n) f>f20fxfv scp devicefon: f i o(n) f=fof f otherfi o(all) f=fon low f (latching) replacefshortedf led(s)fandftogglef en,fvccforfuvlo high v io(all) f>f20fxfv scp deviceflatch-of; f i o(all) f=fof low f (latching) replacefshortedf led(s)fandftogglef en,fvccforfuvlo high open f led(s) no v io(n) ff 50ocf(typ) devicefof; f i o(all) f=fof low f (latching) satisfyft hys f>f0oc; f devicefon; i o(all) f=fon; f togglefen,fvccforf high note:ffreferftofthefapplicationfcircuitfexamplefforfr fandfr 2 fonfpagef23,ffiguref2 .
sc5014 9 applications information (continued) fault protection thef sc50 4f providesf faultf detectionf forf lowf supplyf voltage,fledfrelatedffaults,fboostfconverterfover-voltagef andfthermalfshutdown.fthefopenfdrainfoutputfpinf( flt )f indicatesfafsystemffault.fthefnaturefofftheffaultfcanfbefreadf fromftheffaultfstatusfresistorf(registerfaddress:f0x00)fviafi 2 cf interface.freferftoftablef3fforfafdescriptionfofftheffaultf protectionfmodes. other possible confgurations dependingfonfdifferentfapplicationfrequirements,fthef sc50 4fcanfalsofbefeasilyfconfguredftofotherftopologies,f suchfasfthefsepicfconfgurationfshownfinffiguref4,fpagef 24.f li-ion powered display confguration iffafli-ionfpoweredfdisplayfapplicationfisfrequired,fv cc f fisf neededftofpowerfwithf5v.fhowever,fv in fcanfbefsetflowerf fromf3vftof4.2vfforfexample.fanfadvantagefoffthisftypefoff confgurationfisfthatfitfprovidesfhigherfefciency.ffpleasef useffiguref3fonfpagef23fforfreference. high output voltage confguration iffafhighfoutputfvoltagefapplicationfisfrequired,fanfaddi - tionalfexternalfcascodefmosfetfcanfbefaddedfonfeachfiof pinftofmeetfsuchfrequirement,fpleasefreferftoffiguref5fonf pagef24fforfreference. infthisfcase,fthefupperflimitfonfthefoutputfvoltagefisfmainlyf determinedfbyfthefratingfoffthefexternalfmosfet,fheatf dissipation,fetc. pcb layout considerations thefplacementsfoffthefpowerfcomponentsfoutsidefthef sc50 4fshouldffollowftheflayoutfguidelinesfoffafgeneralf boostfconverter.fthefdetailedfapplicationfcircuitfisfusedf asfanfexample. capacitorf(c2)fshouldfbefplacedfasfclosefasfpossibleftof thefvccfandfagndftofachievefthefbestfperformance. capacitorf(c )fisfthefinputfpowerfflteringfcapacitorfforf thefboost.fitfneedsftofbeftiedftofpgnd. . 2. thefconverterfpowerftrainfinductorf(l )fisfthefboostf converterfinputfinductor.fusefwidefandfshortfftracesf connectingfthesefcomponents. thefoutputfrectifyingfdiodef(d )fusesfafschottkyfdiodef forffastfreversefrecovery.ftransistorf(q )fisfthefexternalf switch.fresistorf(r9)fisfthefswitchfcurrentfsensingfresis - tor.ftofminimizefswitchingfnoisefforfthefboostfcon - verter,fthefoutputfcapacitorf(c6)fshouldfbefplacedf suchfthatfthefloopfformedfbyfq ,fd ,fc6fandfr9,fisf minimized.fthefoutputfoffthefboostfconverterfisfusedf tofpowerfupfthefleds.fusefwidefandfshortftracefcon - nectingfpinfndrvfandfthefgatefoffq .fthefgndsfforfr9f andfc6fshouldfbefpgnd.fthesefcomponentsfshouldf befcloseftofthefsc50 4. resistorf(r8)fisfthefoutputfcurrentfadjustingfresistorf forfio fthroughfio4fandfshouldfreturnftofagnd.fplacef itfnextftofthefic. resistorf (r6)f isf thef switchingf frequencyf adjustingf resistorfandfshouldfreturnftofagnd.fplacefitfnextftof thefic. thef decouplingf capacitorf (c3)f forf pinf reff shouldf returnftofagnd.fplacefitfnextftofthefic. resistorsf(r4,fr5)fformfafdividerftofsetfthefscpflevel,fr4f shouldfreturnftofagnd.fplacefitfnextftofthefic. resistorsf(r2,fr )fformfafdividerftofsetfthefuvloflevelf forfuvlofpin.fr fshouldfreturnftofagnd.fplacefitfnextf tofthefic. r fandfr 0fformfafdividerftofsetfthefovpflevelfforf vout,fr 0fshouldfreturnftofagnd.fplacefitfnextftofthef ic. allftheftracesfforfcomponentsfwithfagndfconnectionf shouldfavoidfbeingfroutedfcloseftofthefnoisyfareas. anfexposedfpadfisflocatedfatfthefbottomfoffthefsc50 4f forfheatfdissipationfandfanalogfground.fafcopperfareaf underneathfthefpadfisfusedfforfbetterfheatfdissipation.f onfthefbottomflayerfoffthefpcbfanotherfcopperfarea,f connectedfthroughfviasftoftheftopflayer,fisfusedfforf betterfthermalfperformance.fthefpadfatfthefbottomfoff thef sc50 4f shouldf bef connectedf tof agnd.f agndf shouldfbefconnectedftofpgndfatfafsinglefpointfforf betterfnoisefimmunity. 3. 4. 5. 6. 7. 8. 9. 0. . 2.
sc5014 20 components selection inductor selection thefchoicefoffthefinductorfafectsfthefconvertersfsteadyf statefoperation,ftransientfresponse,fandfitsfloopfstability.f specialfattentionfneedsftofbefpaidftofthreefspecifcationsf offthefinductor,fitsfvalue,fitsfdcfresistancefandfsaturationf current.fthefinductorsfinductancefvaluefalsofdeterminesf thef inductorf ripplef current.fthef boostf converterf willff operatefinfeitherfccmf(continuousfconductionfmode)forf dcmf(discontinuousfconductionfmode)fdependingfonfitsf operatingfconditions.fthefinductorfdcfcurrentforfinputf currentfcanfbefcalculatedfusingftheffollowingfequation. v i v i in out out in i in - input current;i out C output current; v out C boost output voltage; v in C input voltage; C effciency of the boost converter thenfthefdutyfratiofunderfccmfisfshownfbyftheffollowingf equation. d out d in out v v v v v d v d fCfforwardfconductionfdropfofffoutputfrectifyingf diode f whenfthefboostfconverterfrunsfunderfdcmf(flffl boundary ),fnormallyf thefconverterfhasfhigherf efciency. whenfselectingfanfinductor,fanotherffactorftofconsiderfisf thefpeak-to-peakfinductorfcurrentfripple,fwhichfisfgivenf byftheffollowingfequation: l f d v i sw in l usuallyfthisfpeak-to-peakfinductorfcurrentfripplefcanfbef chosenfbetweenf30%ftof50%foffthefmaximumfinputfdcf current.fthisf givesf thef bestf compromisef betweenf thef inductorfsizefandfconverterfefciency.fthefpeakfinductorf currentfcanfbefcalculatedfusingftheffollowingfequation: l f 2 d v i i sw in in peak -l v forfmostfapplications,fanfinductorfwithfafvaluefoff2.2 hftof 22 hfshouldfbefacceptable,f(referftofthefdetailedfapplica - tionf circuitf onf pagef 23,f figuref 2).fthef inductorf peakf currentfmustfbeflessfthanfitsfsaturationfrating.fwhenfthef inductorfcurrentfisfcloseftofthefsaturationflevel,fitsfinduc - tancefcanfdecreasef20%ftof35%ffromfthef0afvaluefdepend - ingfonfthefvendorfspecifications.ffusingfafsmallfvaluef inductorfforcesfthefconverterfinfdcm,finfwhichfcasefthef inductorfcurrentframpsfdownftofzerofbeforefthefendfoff eachfswitchingfcycle.fitfreducesfthefboostfconvertersf maximumfoutputfcurrentfandfproducesfaflargerfinputf voltagefripple.fthefdcrfoffthefinductorfplaysfafsignifcantf rolefforftheftotalfsystemfefciencyfandfusuallyftherefisfaf trade-offbetweenfthefdcrfandfsizefoffthefinductor.fftablef 4flistsfsomefrecommendedfinductorsfandftheirfvendors. ffffffffffffffffffffff tablef4.ffrecommendedfinductors inductor vendorfwebsite hcm0703,f2.2uh~0uh www.cooperindustries.com ihlp-2525cz-0 ,f4.7uh~0uh www.vishay.com mlpc0730l,f2.2uh~4.7uh www.nec-tokin.com/english output capacitor selection thefnextfdesignftaskfisftargetingfthefproperfamountfoff outputfripplefvoltagefdueftofthefconstant-currentfledf loads.fusuallyfx5rforfx7rfceramicfcapacitorfisfrecom - mended.fthefceramicfcapacitorfminimumfcapacitancef neededfforfafgivenffripplefcanfbefestimatedfusingftheffol - lowingfequation: ripple sw out out in out out v f v i v v c v
sc5014 2 application information (continued) v ripple C peak to peak output ripple. thefripplefvoltagefshouldfbeflessfthanf200mvf(pk-pk)ftof ensurefgoodfledfcurrentfsinkfregulation.fforfexample,faf typicalf applicationf wheref 20ma/channelf currentf isf needed,ftheftotalfoutputfcurrentfforf4fchannelsfwillfbef 480ma,fandf6xf4.7 fffcapacitorsfarefrecommended. duringfloadftransient,fthefoutputfcapacitorfsuppliesforf absorbsfadditionalfcurrentfbeforefthefinductorfcurrentf reachesfitsfsteadyfstatefvalue.flargerfcapacitancefhelpsf withfthefovershoot/undershootfduring loadftransientfandf loopfstability.f input capacitor selection x5rforfx7rfceramicfcapacitorfisfrecommendedfforfinputf bypassfcapacitor.ffaf ffcapacitorfisfsufcientfforfthefvccf input.fbypassfthefvinfinputfwithfaf 0 fforflargerfceramicf capacitor. output freewheeling diode selection schottkyfdiodesfarefthefidealfchoicefforfthefsc50 4fdueftof theirflowfforwardfvoltagefdropfandffastfswitchingfspeed.ff tablef5fshowsfseveralfdiferentfschottkyfdiodesfthatfworkf properlyf withf thef sc50 4.fverifyf thatf thef diodef hasf af voltagefratingfgreaterfthanfthefmaximumfpossiblefoutputf voltage.fthefdiodefconductsfcurrentfonlyfwhenfthefpowerf switchfisfturnedfof.fthefdiodefmustfbefratedftofhandlefthef averagef outputf current.f af diodef ratedf forf af averagef currentfwillfbefsufcientfforfmostfdesigns. tablef5.ffrecommendedfrectiferfdiodes rectiferfdiode vendorfwebsite dfls40 www.diodes.com ss4/5/6,fss24/25/26 www.vishay.com external power mosfet selection thefboostfconverterfinfsc50 4fusesfanfexternalfpowerf mosfetftofregulatefthefoutputfvoltagefandfoutputfpowerf tofdrivefledfloads.ffthisfboostfswitchingfstructurefhasfanf advantagef inf thatf thef sc50 4f isf notf exposedf tof highf voltage.ffonlyfthefexternalfpowerfmosfet,ffreewheelingf diodefandfthefinductorfwillfbefexposedftofthefoutputf voltage.fthefexternalfpowerfmosfetfshouldfbefselectedf withfitsfvoltagefratingfhigherfthanfthefoutputfvoltagefbyf minimumf30%.fthefcurrentfratingfshouldfbefenoughftof handlefthefinductorfpeakfcurrent.flowfr ds (on)fmosfetsf arefpreferredfforfachievingfbetterfefciency. thefgdf(gatefdriver)fonfsc50 4fprovidesf af(peak)fcurrentf drivingfcapabilityfwhichfisfsuitablefforfmostfmosfetsfforf highffrequencyfoperation.fthefaveragefcurrentfrequiredftof drivefthefmosfetfisfgivenfbyftheffollowingfequation. i gate = q g x f sw q g gate charge thefr ds(on) fandfitsfrmsfcurrentfi s_rms foffthefpowerfmosfetf willfgeneratefthefconductionflossfusingftheffollowingf equation. p cond = i s_rms 2 x r ds(on) thefmosfetsfswitchflossfcanfbefcalculatedfusingftheffol - lowingfequation. p sw = ? x v in x i l_peak x f sw x (t on + t off ) where t on and t off are the mosfets on and off time and they can be estimated by the following equations. ( ) ( ) g plateau gd r on r / v q t t + ? + = 5 5 ( ) g plateau gd f off r / v q t t + + = 5 whereft r ,ft f ,fq gd fandfv plateau fcanfusuallyfbeffoundffromfdata - sheetfoffthefselectedfmosfet.fr g fisfthefresistancefoffthef optionalfresistorfconnectedfinfseriesfonfthefgatefoffthef mosfet.
sc5014 22 components selection (continued) current sensing resistor selection thefswitchfcurrentfisfsensedfviafthefcurrentfsensingfresis - tor,fr cs .fthefsensedfvoltagefatfthisfpinfisfusedftofsetfthef peakfswitchfcurrentflimitfandfalsofusedfforfsteadyfstatef regulationfoffthefinductorfcurrent.fthefcurrentflimitfcom - paratorfhasfaftripfvoltagefoff0.4vf(typical).fr cs fvaluefisf chosenftofsetfthefpeakfinductorfandfswitchfcurrentfusingf theffollowingfequation. i 2 sw(peak) = 0.4/r cs thefpowerfdissipationfinfr sns fcanfbefcalculatedfusingfthef followingfequations. p r_cs = i rms 2 x r cs i rms = d x [i o /(1-d)] 2 i o = output dc current, d = duty cycle forftheftypicalfapplicationfcircuitfshownfinfthefdetailedf applicationfcircuitf(pagef23,ffiguref2),fthefpowerfdissipa - tionfonfthefsensingfresistorfisfshownfbyftheffollowingf equations. assumingfv in f=f6vfandfv out f=f3 .5v,fthusfdf=f8%, p r_cs = 0.81 x (0.48/0.19) 2 x 0.08 = 0.414(w) forfthisfexample,faf0.08ff %fthick-flmfchipfresistorfratedf atf wfcanfbefused. pll filter component selection thefdetailedfapplicationfcircuitfonfpagef23,ffiguref2fshowsf thefoptimalfr/cfflterfcomponentsfforfthefpllfcompensa - tion.fthesefarefoptimizedfforfinternalf mhzfswitchingffre - quency.f pleasef contactf semtechf powerf managementf applicationfgroupfiffafdifferentfswitchingffrequencyfisf selected.
sc5014 23 figure 2 application circuit example, 40 led @ 100ma c 5 2 . 7 pf v in ( 6 - 27 v ) sc 5014 vcc en uvlo scp r e f f s e t c p l l scl sda i s e t pwm io 4 io 3 io 2 io 1 ovp c s p g n d n d r v r 4 c 4 100 pf r 3 c 6 q 1 c 12 sda r 8 r 15 c 1 scl c 3 l 1 r 9 r 1 pwm r 12 v cc ( 5 v ) r 6 r 2 gnd r 11 vout 10 wleds per channel flt flt 2 . 2 f 10 k pgnd 10 f / 35 v x 2 pcs 4 . 7 f / 50 v x 6 pcs 1 f 24 . 3 k 80 m 357 k 10 k 25 . 5 k r 7 , 110 k 20 k 10 k r 5 , 40 . 2 k 100 k d 1 10 k 4 . 7 h aon 7244 b 260 pad figure 3 li-ion powered display application circuit example, 20 led @ 20ma v in ( 3 - 4 . 2 v ) s c 504 vcc en uvlo scp r e f f s e t n c scl sda i s e t pwm io 4 io 3 io 2 io 1 ovp c s p g n d n d r v r 4 r 3 c 6 q 1 c 12 sda r 8 r 15 c 1 scl c 3 l 1 r 1 pwm r 12 v cc ( 5 v ) r 6 r 2 gnd r 11 vout 5 wleds per channel flt flt 2 . 2 f / 10 v 10 k pgnd 10 f / 6 . 3 v x 2 pcs 1 f 13 k 100 m 249 k 10 k 127 k 20 k 10 k r 5 , 60 . 4 k 100 k d 1 10 k si 2318 b 140 pad r cs
sc5014 24 c 5 2 . 7 pf v in ( 6 - 27 v ) s c 504 vcc en uvlo scp r e f f s e t c p l l scl sda i s e t pwm io 4 io 3 io 2 io 1 ovp c s p g n d n d r v r 4 c 4 100 pf r 3 q 1 c 12 sda r 8 r 15 c 1 scl c 3 l 1 r 1 pwm r 12 v cc ( 5 v ) r 6 r 2 gnd r 11 vout flt flt 2 . 2 f pgnd 1 f r 7 , 110 k 20 k 10 k r 5 pad d 1 c 6 l 2 c 8 r cs figure 4 sepic confguration c 5 2 . 7 pf v in ( 12 - 19 v ) s c 504 vcc en uvlo scp r e f f s e t c p l l scl sda i s e t pwm io 4 io 3 io 2 io 1 ovp c s p g n d n d r v r 4 c 4 100 pf r 3 c 6 q 1 c 12 sda r 8 r 15 c 1 scl c 3 l 1 r 1 pwm r 12 v cc ( 5 v ) r 6 r 2 gnd r 11 vout up to 70 v 20 wleds per channel flt flt 2 . 2 f 10 k pgnd 10 f / 25 v x 3 pcs 2 . 2 f / 100 v x 6 pcs 1 f 75 k 50 m 787 k 10 k 25 . 5 k r 7 , 110 k 20 k 10 k r 5 , 40 . 2 k 250 k d 1 10 k aon 6482 dfls 1100 pad v in 3 . 3 h r cs figure 5 cascode confguration drives 80 leds@100ma
sc5014 25 acknowledgesfandfthefmasterfterminatesftheftransferfwithf thefstopfconditionf[p]. (2) combined format read afterfthefstartfconditionf[s],fthefslavefaddressfisfsent,ffol - lowedfbyfanfeighthfbitfindicatingfafwrite.ffthefsc50 4fi 2 cf thenfacknowledgesfthatfitfisfbeingfaddressed,fandfthef masterfrespondsfwithfanf8-bitfdatafbytefconsistingfoffthef registerfaddress.fthefslavefacknowledgesfandfthefmasterf sendsfthefrepeatedfstartfconditionf[sr].foncefagain,fthef slavefaddressfisfsent,ffollowedfbyfanfeighthfbitfindicatingf afread.fthefslavefrespondsfwithfanfacknowledgefandfthef 8-bitfdataffromfthefpreviouslyfaddressedfregister;fthef masterfthenfsendsfafnon-acknowledgef(nack).ffinally,fthef masterfterminatesftheftransferfwithfthefstopfconditionf[p]. (3) stop separated reads stop-separatedfreadsfcanfalsofbefused.fthisfformatfallowsf afmasterftofsetfupfthefregisterfaddressfpointerfforfafreadf andfreturnftofthatfslavefatfaflaterftimeftofreadfthefdata.finf thisfformatfthefslavefaddressffollowedfbyfafwritefcommandf aref sentf afterf af startf [s]f condition.fthef sc50 4f thenf acknowledgesf itf isf beingf addressed,f andf thef masterf respondsfwithfthef8-bitfregisterfaddress.fthefmasterfsendsf afstopforfrestartfconditionfandfmayfthenfaddressfanotherf slave.fafterfperformingfotherftasks,fthefmasterfcanfsendfaf startf orf restartf conditionf tof thef sc50 4f withf af readf command.fthefdevicefacknowledgesfthisfrequestfandf returnsf thef dataf fromf thef registerf locationf thatf hadfffffffff previouslyfbeenfsetfup. serial interface the i 2 c general specifcation thefsc50 4fisfafread-writefslave-modefi 2 cfdevicefandf compliesfwithfthefnxpfb.v.fi 2 cfstandardfversionf2. ,fdatedf januaryf2000.fthefsc50 4fhasf fuser-accessiblefinternalf 8-bitfregisters.fthefi 2 cfinterfacefhasfbeenfdesignedfforf programfflexibility,fsupportingfdirectfformatfforfwritef operation.freadfoperationsfarefsupportedfonfbothfcom - binedfformatfandfstopfseparatedfformat.fwhileftherefisfnof autofincrement/decrementfcapabilityfinfthefsc50 4fi 2 cf logic,faftightfsoftwarefloopfcanfbefdesignedftofrandomlyf accessfthefnextfregisterfindependentfoffwhichfregisterf youfbeginfaccessing.fthefstartfandfstopfcommandsfframef thefdata-packetfandfthefrepeatfstartfconditionfisfallowedf iffnecessary. limitations to the i 2 c specifcations thefsc50 4fonlyfrecognizesf7-bitfaddressing.fthisfmeansf thatf 0-bitfaddressingfandfcbusfcommunicationfarefnotf compatible.f thefdevicefcanfoperatefinfeitherfstandardf modef( 00kbit/s)forffastfmodef(400kbit/s). slave address assignment thef7-bitfslavefaddressfisf0 0 f x.fthefeighthfbitfisfthef datafdirectionfbit.f0x5ffisfusedfforfreadfoperationfandf 0x5efisfusedfforfwritefoperation. supported formats thefsupportedfformatsfarefdescribedfinftheffollowingf subsections. (1) direct format write thefsimplestfformatfforfanfi 2 cfwritefisfdirectfformat.ffafterf thefstartfconditionf[s],fthefslavefaddressfisfsent,ffollowedf byfanfeighthfbitfindicatingfafwrite.fthefsc50 4fi 2 cfthenf acknowledgesfthatfitfisfbeingfaddressed,fandfthefmasterf respon dsfwithfanf8-bitfdatafbytefconsistingfoffthefregisterf address.fthefslavefacknowledgesfandfthefmasterfsendsf thefappropriatef8-bitf datafbyte.foncefagain,fthefslavef
sc5014 26 i 2 c direct format write slave address register address data s w a a a p s C start condition w C write = 0 a C acknowledge ( sent by slave ) p C stop condition slave address C 7 - bit register address C 8 - bit data C 8 - bit i 2 c stop separated format read slave address register address slave address b data nack s w a a s / sr r a p p slave address s register address setup access master addresses other slaves register read access s C start condition w C write = 0 r C read = 1 a C acknowledge ( sent by slave ) nak C non - acknowledge ( sent by master ) sr C repeated start condition p C stop condition slave address C 7 - bit register address C 8 - bit data C 8 - bit i 2 c combined format read slave address register address slave address data nack s w a a sr r a p s C start condition w C write = 0 r C read = 1 a C acknowledge ( sent by slave ) nak C non - acknowledge ( sent by master ) sr C repeated start condition p C stop condition slave address C 7 - bit register address C 8 - bit data C 8 - bit
sc5014 27 register map address bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 reset value description 0x00 clf pll_rdy led_ short led_ open otp ovp fault 0x00 faultfstatus 0x0 wnd wnd0 fast_ freq flt_en phase_ shift int_ duty int_ pwm 0xb5 devicefcontrol 0x02 idac4 idac3 idac2 idac idac0 0xf analogfdimmingf control 0x03 d9 d8 0x00 dimmingfdutyfcyclef controlf 0x04 d7 d6 d5 d4 d3 d2 d d0 0x00 dimmingfdutyfcyclef controlf2 0x05 freq7 freq6 freq5 freq4 freq3 freq2 freq freq0 0x00 dimmingffrequencyf select 0x06 npll7 npll6 0x00 pllfdividerfmsb 0x07 npll5 npll4 npll3 npll2 npll npll0 npll9 npll8 0x00 pllfdividerflsb2 0x08 npll7 npll6 npll5 npll4 npll3 npll2 npll npll0 0x08 pllfdividerflsb 0x09 fade_en fade_ type step_ mul2 step_ mul step_ mul0 0x80 fadefoptions 0x0a fade_ rate6 fade_ rate5 fade_ rate4 fade_ rate3 fade_ rate2 fade_ rate fade_ rate0 0x00 fadefrate
sc5014 28 defnition of registers and bits fault status register bit field defnition read / write description 0x00f[7] clf w clearflatchingffagsfbit.f f (setf=f ftofclearfotp,fled_open,fled_shortfandfmaskfovpfforf32ftof64s) 0x00f[6] pll_rdy r pllfreadyfstatus 0x00f[5] led_short r oneforfmorefledfstringsffaultedfshorted 0x00f[4] led_open r oneforfmorefledfstringsffaultedfopen 0x00f[2] otp r thermalfshutdownf( f=fthermalfotpffault) 0x00f[] ovp r outputfover-voltageffaultf(f f=fovpf) 0x00f[0] fault r orfoffallffaultfconditionsf(0=fnoffault,f f=ffaultfcondition)
sc5014 29 device control register bit field defnition read / write description 0x0f[7:6] win[:0] r/w afmodifedfdutyfcyclefsentfintofthefpwmifpinfreplacesfthefexistingfsavedfdutyfcyclefwhenfitsf deviationffromfthefsavedfdutyfisfoutsidefthefwindowfforftwofconsecutivefsamples.f 00f=f0fbitsf(nofwindow) 0f=f fbitfwindow 0f=f2fbitfwindow f=f3fbitfwindow 0x0f[5] fast_freq r/w determinesfthefledfpwmfdimmingffrequencyfselection: f=fhighfpwmfdimmingffrequencyfmodefassumingf9-bitfpwmfdutyfcyclefdimming,fdividingf thefsystemfclockf 0mhzf/f(52fxf(freq+)). 0f=flowfpwmfdimmingffrequencyfmodefassumingf 0-bitfpwmfdutyfcyclefdimming,fdividingf thefsystemfclockf 0mhzf/f(024fxf(freq+)). 0x0f[4] flt_en r/w thisfbitfenablesffaultfchecking: 0f=fled_openfandfled_shortffaultsfarefnotfchecked. f=fled_openfandfled_shortffaultsfarefchecked. 0x0f[2] ph_shift r/w enablesfstring-by-stringfphasefshifting.fthisfisfafdontfcarefiffint_pwm=0. 0f=fphasefshiftingfdisabled. f=fphasefshiftingfisfenabled. 0x0f[] int_duty r/w determinesfthefdutyfcyclefsource.ffthisfisfafdontfcarefiffint_pwmf=f0. 0f=fledfdutyfcyclefisfsetfbyfthefpwmifinput. f=fledfdutyfcyclefisfsetfbyfthef 0-bitfdutyfcyclefcontrolfregisters. 0x0f[0] int_pwm r/w setsfthefledfpwmfdimmingfsource. 0f=fledfpwmfdimmingfdrivenfdirectlyffromfthefpwmifinputfsourcef(directfpwmfdimming). f=fledfpwmfdimmingfdrivenffromfanfinternalfoscillatorf(requiredfforfphase-shiftedfpwmf dimming);fenablesfthefpll. analog dimming control register bit field defnition read / write description 0x02f[4:0] idacf[4:0] rf/fw 5-bitfanalogfdimmingfregisterffthefledfcurrentfcanfadjustedfinf32fstepsffromf0maftofmaxf valuefdeterminedfbyfr iset . defnition of registers and bits (continued)
sc5014 30 defnition of registers and bits (continued) dimming duty cycle control register bit field defnition read / write description 0x03f[:0] f 0x04f[7:0] df[9:0] rf/fw 0-bitfpwmfbrightnessfsettingffthisfvaluefisfspreadfoverfregisters:ff0x03f(msb)fandf0x04f (lsb). dimming frequency select register bit field defnition read / write description 0x05f[7:0] freqf[7:0] rf/fw thisfregisterfsetsfthefledfdimmingffrequency. fast_freqf=f ,fthenfledfdimmingffrequencyfisfequalftof 0mhzf/f(52fxf(freq+)). fast_freqf=f0,fthenfledfdimmingffrequencyfisfequalftof 0mhzf/f(024fxf(freq+)). pll control registers bit field defnition read / write description 0x06f[:0] f 0x07f[7:0] f 0x08f[7:0] npllf[7:0] rf/fw thesefregistersfsetfthefpllffdividerfvaluefffthefsystemfclockfisfintendedftofrunfatf 0mhz;fthisf valuefdividesfthefsystemfclockfdownftofaffrequencyfcomparableftofthefsyncfsignalsffrequen - cyftofallowfpllfsynchronization.ftypicalfvaluesfarefshownfbelow. f in n n in 60fhz 69,982 0x02f-f0x97f-f0xfe 0mhz fmhz 8 0x00f-f0x00f-f 0x08 0mhz fade options registers bit field defnition read / write description 0x09f[7] fade_en r/w enablesftheffadingffeature. fade_enf=f0:fnoffading;fjumpsfdirectlyftofnewfpwmfvalue. fade_enf=f :fenablesffading. 0x09f[6] fade_type r/w selectsftheffadingftype. fade_typef=f0:flogarithmicffading. fade_typef=f :flinearffading.
sc5014 3 bit field defnition read / write description 0x09f[2:0] step_mul f [2:0] r/w usedftofspeedfupffadeftime,fwhenfselectedfledfpwmfdimmingffrequencyfisflow.fdefnefaf2 n f multiplierfofftheffadefamount. step_mul[2:0]f=f000,fn=0,ffmultiplierf=f step_mul[2:0]f=f00,fn=,ffmultiplierf=f2 f=f2 step_mul[2:0]f=f00,fn=2,ffmultiplierf=f2 2 f=f4 step_mul[2:0]f=f0,fn=3,ffmultiplierf=f2 3 f=f8 step_mul[2:0]f=f00,fn=4,ffmultiplierf=f2 4 f=f6 step_mul[2:0]f=f0~,fn=5,ffmultiplierf=f2 5 f=f32 fade rate register bit field defnition read / write description 0x0af[6:0] fade_rate f [6:0] rf/fw defnesfhowfoftenfthefdutyfisfchangedfduringfaffade.f fadefratef=fpwmfoutputfratef/f( f+ffade_rate[6:0]) defnition of registers and bits (continued)
sc5014 32 bxn bbb c a b d1 e1 e d/2 .001 max .002 - .039 nom 0.80 0.02 (0.20) 0.90 controlling dimensions are in millimeters (angles in degrees). coplanarity applies to the exposed pad as well as the terminals. notes: 2. 1. 1 2 n e1 .100 .106 .110 2.55 2.70 2.80 pin 1 indicator 4.10 3.90 4.00 4.10 3.90 .157 .154 .161 .154 .161 aaa c a c (laser mark) d e b a1 a a2 seating plane lxn e/2 inches .020 bsc b .007 bbb aaa n d1 e l e d .012 .100 dim a1 a2 a min .000 - .031 0.30 0.18 .012 0.25 .010 0.50 2.80 0.30 2.55 .004 .004 20 .016 .157 .106 .020 .110 0.10 0.10 20 0.40 4.00 2.70 0.50 bsc millimeters max 0.05 - 1.00 dimensions min 0.00 - nom (.008) .035 outline drawing mlpq-20 4x4
sc5014 33 land pattern mlpq-20 4x4 dimensions k h g z x p (c) company's manufacturing guidelines are met. 4.80 .189 z y failure to do so may compromise the thermal and/or thermal vias in the land pattern of the exposed pad shall be connected to a system ground plane. functional performance of the device. 2. this land pattern is for reference purposes only. consult your manufacturing group to ensure your notes: 1. dim x y h k p c g millimeters inches (3.95) .010 .033 .122 .020 .106 .106 (.156) 0.25 0.85 2.70 0.50 2.70 3.10
semtechfcorporation powerfmanagementfproductsfdivision 200fflynnfroad,fcamarillo,fcaff930 2 phone:ff(805)f498-2 ffffax:ff(805)f498-3804 www.semtech.com contact information sc5014 34 ?fsemtechf20 2 allfrightsfreserved.freproductionfinfwholeforfinfpartfisfprohibitedfwithoutfthefpriorfwrittenfconsentfoffthefcopyrightf owner.fthefinformationfpresentedfinfthisfdocumentfdoesfnotfformfpartfoffanyfquotationforfcontract,fisfbelievedftofbef accuratefandfreliablefandfmayfbefchangedfwithoutfnotice.fnofliabilityfwillfbefacceptedfbyfthefpublisherfforfanyfconse - quencefoffitsfuse.fpublicationfthereoffdoesfnotfconveyfnorfimplyfanyflicensefunderfpatentforfotherfindustrialforfintellec - tualfpropertyfrights.fsemtechfassumesfnofresponsibilityforfliabilityfwhatsoeverfforfanyffailureforfunexpectedfoperationf resultingffromfmisuse,fneglectfimproperfinstallation,frepairforfimproperfhandlingforfunusualfphysicalforfelectricalfstressf including,fbutfnotflimitedfto,fexposureftofparametersfbeyondfthefspecifedfmaximumfratingsforfoperationfoutsidefthef specifedfrange. semtechfproductsfarefnotfdesigned,fintended,fauthorizedforfwarrantedftofbefsuitablefforfusefinflife- supportfapplications,fdevicesforfsystemsforfotherfcriticalfapplications.finclusionfoffsemtechfproductsf infsuchfapplicationsfisfunderstoodftofbefundertakenfsolelyfatfthefcustomersfownfrisk.fshouldfafcustomerf purchaseforfusefsemtechfproductsfforfanyfsuchfunauthorizedfapplication,fthefcustomerfshallfindemnifyfandfholdf semtechfandfitsfofcers,femployees,fsubsidiaries,fafliates,fandfdistributorsfharmlessfagainstfallfclaims,fcostsfdamagesf andfattorneyffeesfwhichfcouldfarise. notice:fallfreferencedfbrands,fproductfnames,fservicefnamesfandftrademarksfarefthefpropertyfofftheirfrespectivef owners.

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