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1、LED Lighting Driver IC Introduction2ContentsLED Lighting Driver IC OverviewAC input to constant current LED driver - IsolatedAC input to constant current LED driver - Non-isolated DC to CC SolutionApplicationsSelection Guide 3LED Lighting Driver IC Overview4LED Lighting Driver IC OverviewLED Lightin
2、gAC/CCDC/CCIsolatedNon-isolatedWith ETWithout ETE26/E27/E17, T5/T8 Par30/Par38, Street lightGU10, E26/E27/E17 T5/T8, Par30/Par38MR16, AR111Street light, car light, desk light, freeze light, projector Emergency light 5AC input to constant current LED driver - Isolated6AC Input Solution - IsolatedAppl
3、icationE27, GU10 . Bulb, Par 30, Par 38T5, T8 . Light bar, Freeze lightStreet light, Desk lightRichtek advantageHigh-precision constant current control to limit current accuracy in +/-5% range on mass production. Small package and high integrated solution with less external components to fit into a
4、small bulb or light barVery low quiescent currentDimming on secondary side to provide better accuracy7Secondary side CC/CV controllerAC to CC Isolated secondary side CC/CV controller & dimmingRT8456RT8454RT8457Single channel CC/CV controllerSingle channel CC/CV controller with dimmingMulti-channel C
5、C/CV controller with dimminglEasilyworkwithanykindofprimarysidetopology.lProvidehighprecisionLEDcurrent.lLEDcurrentaccuracydoesnotvarywiththeaccuracyoftransformer.lOVPsupport8RT8456 Secondary-side constant Current ControllerSecondary side LED current regulationSupport LED voltage up to 45VHigh accur
6、acy LED current threshold control over wide input voltage and temperature range0.6mA operation currentProgrammable LED current through 60mV sense resisterProgrammable OVPEasily connected to different kinds of primary side solutionsTSOT 23-69RT8457: Dimmable secondary side constant current controller
7、LED voltage up to 45VSupport Triac dimming, PWM dimming, analog dimmingHigh accuracy LED current threshold control over wide input voltage and temperature range Programmable LED current through 60mV sense resisterProgrammable OVPEasily connected to different kinds of primary side solutionsSOP-8Dimmi
8、ngInput10RT8454 AC-CC 6-Ch Current RegulatorsVcc up to 50VProgrammable channel current3% current sense amplifier input offsetEasy dimmingProgrammable soft start and OVPAutomatic detecting unconnected AND/OR broken channel to avoid output over voltageVcc under voltage lockout and Thermal shutdownOne
9、LDO controller embedded11RT8454 AC-CC One-Stage Driving Scheme12Application Tip: RT8454Channel Number ExtensionVauxAC to DC Primary Side CircuitOpto-CouplerAC Power Lines13Applications: Isolated E26/27, T5/T8, PAR30/38.Primary side solution example1.Flyback: R7912 (MOS inside) R7732(MOS ext.)Low PF,
10、 small output current ripple, good efficiency, good for no-PF requirement condition.2.Valley-fill PFC+FlybackFor small power (0.7 application.3.Active PFC+FlybackHigh PF (0.9), lower efficiency, small output current ripple, good for high power design.4.PFC single stageHigh PF (0.9), low cost, need b
11、ig output cap to reduce current ripple. Good for small power, low cost design.5.LLCHigh efficiency, high cost. Good for high power, high performance design.6.Primary side constant current : R7710Current accuracy is suffered from transformer accuracy. Good for current accuracy 90%possible)lCheapandsi
12、mpleexternalcomponentslVerywideinputvoltagerange(16V400Vorhigher)lStableLEDcurrentoverwideinputvoltagerangelWorkswithstandardseriesdrumchokeinductorslSupportOVP&OCPlSmallPCBtotofitGU10,E17.19Three RT8458 applications1.Typical applicationlAdvantagelVery good line regulation. LED current variation bet
13、ween 110V/220V AC input is minor. (+/-2%)lSmall input/Output caplSimple external componentslGood for application do not need PFC.lDisadvantagelLow PF (About 0.6)2.Valley-fill PFC+RT8458lAdvantagelPF at 0.70.9 for low power application (0.7 designlDisadvantagelBig cap for high power or high PF applic
14、ation.3.Active PF + RT8458lAdvantagelHigh PF (0.95)lGood for high power, high PF designlDisadvantagelHigher costlLower efficiency20RT8458 typical application circuitOVP optionVout31VEMI improvement21High-efficiency universal input designVin.ac (V)Pin(W)V-LED (V)I-LED (A)Pout (W)Eff. (%)9010.2536.20
15、0.2579.303 90.76 11010.2236.29 0.2579.327 91.26 13010.2936.19 0.2579.300 90.38 18010.1936.02 0.2579.257 90.85 22010.2136.02 0.2579.257 90.67 26010.2336.06 0.2579.267 90.59 22RT8458 efficiency vs. LEDsLEDcurrent=350mA23RT8459 High PF, floating buck LED driver for non-isolated applicationlUniqueself-b
16、iasingfloatingbuckdrivertopologylTrueaverageLEDcurrentsenseforhighPFapplicationlCheapandsimpleexternalcomponentslVerywideinputvoltagerange(16V400Vorhigher)lStableLEDcurrentoverwideinputvoltagerangewithhighPFsupportlWorkswithstandardseriesdrumchokeinductorslSupportOVP&OCPlSmallPCBtotofitGU10,E17.24RT
17、8459 typical application circuit25RT8459 test result with universal input* Good line regulation for universal input with high PF support* NOTED: Higher output current ripple & big output cap. for PFC single stage design8459 Vout=44V/200mA/15LEDsVin.ac (V)Vo (V)Io (mA)Pin (W)Po (W)PFEff. (%)current o
18、ffset (%)9043.33 1949.38.41 0.980 90.39 -1.02%11043.37 1969.268.50 0.981 91.80 0.00%13043.35 1959.198.45 0.985 91.98 -0.51%18043.31 1919.038.27 0.972 91.61 -2.55%22043.36 1949.238.41 0.955 91.14 -1.02%26443.41 1969.428.51 0.932 90.32 0.00%26How to choose the driving topology?NeedPFC?RT8458typicalapp
19、licationNOSmalloutputcurrentripple?RT8459typicalapplicationValley-fillPFC+RT8458goodforsmallpower,PFin0.70.9ActivePFC+RT8458,goodforhighpowerdesignorPF0.9NO27DC to CC Solution28Richteks Product - DC to Constant CurrentConverterControllerRT8480RT8452RT8450BRT8482RT8453BRT8470RT8488ApplicationMR16, AR
20、111Street light, Desk light, Freeze lightCar light, Projector lampSolar lighting, Emergency lightRT847129Richteks Product - DC to Constant CurrentRichtek advantageCover wide input/output voltage range and support different kinds of topology include buck, boost, buck-boost, SEPICAccurate output curre
21、nt over wide temperature rangeStable output current vs. input/output voltage changeEasy Dimming : Analog, PWM or PWM Converting to Analog with One External Capacitor, Triac dimmingSupport high-speed PWM dimming up to 50kHzBetter reliability with bipolar processCost competitive30Selection Guide for D
22、C to CC ProductsDC Input to Constant CurrentPart NumberVin(V)Max Vout(V)LED current per string (mA)Max Efficiency(%)LED StringTopologyRT8450A4.540+Zener drop50UP to 1.5A 951Buck,Boost,Buck-BoostRT8450B4.540+Zener drop50UP to 1.5A 951Buck,Boost,Buck-BoostRT84524.536+Zener drop48External MOSFET 951Buc
23、k,Boost,Buck-BoostRT84534.54038UP to 1.5A 951BuckRT84804.540+Zener dropLimited by external MOSFETExternal MOSFET 931Boost, SEPICRT84824.536+Zener drop48External MOSFET 951Buck,Boost,Buck-BoostRT847073028UP to 1A951BuckRT8488736+Zener dropLimited by external MOSFETExternal MOSFET926Boost31Application
24、s32Applications: MR16Major solutionsRT8470 low cost solutionLowest cost solutionAbout 70% Electronic Transformer (ET) compatibilityDifferent brightness with different ET connectedVery popular in ChinaRT8453 high ET compatibility solutionVery high ET compatibilityKeep same brightness with different E
25、T connectedSpecial applicationsRT8453 dimmable solutionDimmable with minor cost added from the previous solutionSame performance as the previous solution without dimmer connectedET limitedWith selected ET, about 50% dimmer can dim pretty wellRT8453 non electrolytic cap solutionHigh ET compatibility
26、with square wave outputRT8453 three-step dimmingSupport three-step dimming with three-step dimming controller addedUse ON/OFF break to switch between three steps33Application: MR16 (RT8470 BUCK-a typical low cost design)34MR16RT8470 BuckCH1: VinCH4: IinCH1: LED voltageCH4: LED currentAverageLEDcurre
27、ntwillbedifferentwithdifferentETconnected35Application: RT8453 MR16Excellent electronic transformer compatibilityHigh efficiency, stable output LED currentSupport Triac dimming with selected ET and Dimmer but no extra cost addedNo flicker with most of the ET36Application: RT8453 MR16CH1: VinCH4: Iin
28、CH1: LED voltageCH4: LED currentVerystableLEDcurrentwithdifferentETconnected37Applications: Street Light (I)AC PowerOther Control SignalsMCUNTCSense LED Temp.Gx6VbaseDimFBx6Vaux6 Current SourcesRT8454CSx6.6 CHs.PFC +AC2DCPrimary SideCircuitOpto38Applications : Street Light (II)PFC AC2DCSolar CellLiF
29、ePO3 BatteriesAC PowerOther Control SignalsMCUNTCSense LED Temp.Gx6DC 12V48VGateSenseDimFBx6GbiasVaux6 Current SourcesRT8488CSx6.6 CHs.(Either one or both)39Applications : Street Light (III)PFC AC2DCSolar CellLiFePO3 BatteriesAC PowerOther Control SignalsMCUNTCSense LED Temp.Thermal FeedbackDC 12V48
30、VGateSenseDimPWMOGbiasVauxDimmingRT8480Up to 40xLEDs (160V)IFBCurrent FB(Either one or both)40Application: Thermal protection41Selection guide42LED Lighting Selection Guide Sorted by ApplicationLED Lighting Selection Guide Sorted by ApplicationApplicationTopologyRichtek SolutionSolid-State Lighting
31、AC or DC InputMR16Buck, Buck-Boost, BoostRT8450B,RT8482,RT8453, RT8470AR111BoostRT8450B,RT8482GU10, E27,PAR30,PAR38Flyback, non-isolatedRT8458, RT8456, RT8457Office LampBoost, Flyback, non-isolatedRT8450B,RT8482, RT8456, RT8458Decoration LightBoostRT8450B,RT8482Street Light, Solar LightBuck, Boost,
32、flybackRT8450B,RT8482,RT8488,RT8454Emergency LightBoostRT8450B,RT8482T5, T8 Light BarFlyback, non-isolatedRT8456, RT8457, RT8458RGB LightBuckRT8453, RT8470Freeze LightBuck, Flyback, non-isolatedRT8450B,RT8453, RT8456, RT8470, RT8458ProjectorSynchronous BuckRT8452Automotive ApplicationInterior LightBuck, SEPIC, Buck-BoostRT8450B,RT8482, RT8488, RT8480Exterior LightBuck, SEPIC, Buck-BoostRT8450B,RT8482, RT8488, RT8480Automotive LightBuck, SEPIC, Buck-BoostRT8450B,RT8482, RT8488, RT8480
