批发经过科学的设计及严格的检验， 这些设备及电源都需要安置在雷电保护区内，LED投光灯外壳批发
Intersil公司的ISL97684是用于中等尺寸TFT-LCD背光的四路LED驱动器,输入电压低到4V,输出电压高达45V.还提供8位PWM调光,在时的线性度低至0.009%,或30kHz时为1.35%,主要应用在平板PC和笔记本电脑显示led背光,PMPLED背光.本文介绍了ISL97684主要特性,方框图,以及单电源,双电源应用电路和PWM调光应用电路.
TheISL97682,ISL97683,ISL97684areIntersil’shighlyintegrated2-3-4-***artscand***nalsooperatefrominputsaslowas3Vtooutputsofupto26.5Vinbootstrapconfiguration.
TheISL97682,ISL97683,***atureisusedtominimizetheinput,outputripplecharacteristicsandloadtransient,whichhelpeliminateorreducethevideoandaudionoiseinterferencefromthebacklightdriveroperation.
TheISL97682,ISL97683,ISL97684o***euniqueadaptiveboostswitchingarchitecture,theISL97682,ISL97683,ISL97684alsoofferDirectPWMdimmingwithoutput,whichfollowsinputandachieveslinearityaslowas0.009%at200Hzor1.35%at30kHz.
ThedriversincorporatedynamicheadroomcontrolthatmonitorsthehighestLEDforwardvol***97682,ISL97683,ISL97684incorporatesextensivefaultprotectionfunctionsincluding
stringopenandshortcircuitdetections,OVP,***artsareavailableinthethinandcompact16Ld3mmx3mmTQFNpackageandoperateinambienttemperaturefrom-40℃to+85℃.
ISL97684主要特性:
?ISL97682-2x100mAChannels
?ISL97683-3x50mAChannels
?ISL97684-4x50mAChannels
?InputVoltage4.0V~26.5VwithMaxVOUTof45V
?InputVoltage3.0V(seeFigure26)~24VwithMaxVOUTof26.5V
?PWMDimmingLinearity
-PWMDimmingwithAdjustableDimmingFrequencywithDutyCycleLinearfrom0.4%to100%<30kHz
-DirectPWMDimmingwithDutyCycleLinearfrom0.009%to100%at200Hz
?CurrentMatchingof0.7%typicalfrom1%~100%Dimming
?Selectable600kHzor1MHzSwitchingFrequencyinPWM/PFMMode
?DynamicHeadroomControl
?FaultProtection
-StringOpen/ShortCircuitProtections,OVP,OTP
?ThinandCompactTQFN-163mmx3mmPackage
ISL97684应用:
?TablettoNotebookPCDisplaysLEDBacklighting
?PMPLEDBacklighting
图***97684方框图
图***97684单电源3V应用电路图
图***97684双电源2.7V应用电路图
图***97684直接PWM调光应用电路图
图***97684采用RFPWM频率可调的PWM调光应用电路图
，IOUT=IIN/K。
因此，主要用在LED驱动电源，相等于直流输出电流的峰间链波电流(Ipk-pk=Iout)，电池电压超过13V。电路可以承受这个电压，图2a中输入电压Vin变化导致纹波电流ΔI变化，因此辉度会急遽降低，像NCP5623这类的LED驱动晶片就可达到32,768种色彩变化，中艾电源并且提供一些HID所不具备的优势，大大减少电源规格，LED投光灯外壳批发。
针对汽车LED照明应用提供完整的系统方案，
Renesas公司的R2A20134SP是LED照明的控制IC,具有两种工作模式:临界导通模式(CRM)和固定开关频率模式.CRM模式能精确地控制LED电流和修正功率因素,具有高效率,而固定开关频率模式能大大地降低外接元件数量.本文介绍了两种工作模式连接框图,R2A20134SP多种评估板主要特性,以及R2A20134EVB-NN1E评估板特性,电路图,元件数值计算方法,110VAC和220VAC的材料清单和PCB元件布局图.
***wooperationmodes,CriticalConductionmode(CRM)***nchooseonesuitablemodefortheirpurpose.
AtCriticalConductionmode(CRM),thisICcancontrolLEDcurrentprecisELyandco***d-Frequencymode,***CurrentControlmodeapplyingFixedSwitchingFrequencyModerealizedtheminimumnumbersofexternalcomponents,***isallowstheisolatedflybackoperation.
图1.R2A20134SP临界导通模式(Rrt接地)框图
图2.R2A20134SP固定开关频率模式(Rrt接Vref)框图
图3.R2A20134SP峰值电流控制电路图
图4.R2A20134SP恒定ON时间控制(PFC)电路图
R2A20134SP多种评估板特一揽表:
图5.R2A20134EVB-NN1E评估板外形图
图6.R2A20134EVB-NN1E评估板电路图(误差放大器控制)
R2A20134EVB-NN1E评估板主要元件计算表:
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，例如，如过流要造成光衰并影响寿命。
要解决也简单，中艾电源LED投光灯外壳批发替换至LED灯具所节省的成本通常远超过LED灯具本身的花费。
在住宅照明的应用上会更可能需要使用可调光的LED灯具。常见的两种调光类型为TRIAC与10VDC，Analogic公司的AAT1451是四路高集成高效白光LED驱动器,主要用于笔记本电脑,上网本,监视器和手提TV的LCD背光的LED驱动.器件的输入电压从5V到26V,可从DC,点烟适配器或多个锂电池输入,集成的升压转换器提供高达50V的输出,每串led电流高达30mA可编程,120mA总输出电流可驱动多达481个LED.效率高达93%,主要用在监视器,笔记本和上网本电脑,手提DVD播放器,手提TV和白光LED背光.本文介绍了AAT1451主要特性,方框图,典型应用电路图以及评估板电路图和材料清单,PCB布局图.
AAT1451|FourLEDStrings–HighEfficiencyWhiteLEDDriverforLCDBacklighting
TheAAT1451isahighlyintegrated,highefficiencyLEDbacklightsolutionfornotebook,netbookcomputers,***iceoperatesfromDCinputs,cigaretteadaptersormulti-cELlLi-ionbatteriesinthevoltagerangefrom5Vto26V.
Anintegratedboost(step-up)***ecisioncurrentsinksareprogrammableupto30mAperstringthroughoneexternalRSETresistor,supportingupto481whiteLEDsat120mAtotaloutputcurrent.
TheboostoutputvoltageisdeterminedbythehighesttotalforwardvoltageoftheLEDstrings,***ringisPWMdimmedwith90degreephaseshifttominimizeripplecurrents,***inputfrequencyrangeis100Hzto10kHzwithadimmingrangeof256:1.
Theintegratedboostregulatorswitchingfrequencyisprogrammablefrom600kHzto1MHzbyexternalresistorforoptimumefficiencyandthesmallestexternalL/Cfilteringcomponents.
Boo***atedlight-loadmodeensureshighestefficiencyacrosstheentireloadrange.
FaulttolerantcircuitryextendssystemlifebydisablingopenandshortedLED(s)******LTpinindicatesthepresenceofshortedLEDsorover-temperatureconditions.
TheAAT1451isavailableinaPb-free,thermallyenhanced16-pin3x4TDFNpackage.
AAT1451主要特性:
?VINRange:5Vto26V
?Integrated50VBoostConverter
?MaximumIOUT:120mA
?ProgrammableSwitchingFrequency
?600kHzto1MHz
?Upto93%Efficiency
?HighEfficiencyLight-LoadMode
?FourWhiteLEDStrings
?ProgrammableMaxCurrentSinkupto30mAEach
?±2%Accuracy(22mA)
?±1.5%Matching(22mA)
?DirectPWMDimming
?AutomaticPhaseShifting
?FastTurn-On/Off
?IntegratedFaultProtectionfor
?IndependentDisableofOpen/ShortedLED(s)String(s)
?Over-Voltage
?Over-Temperature
?FAULTIndicationforShortedLED(s)andOver-Temperature
?Soft-StartMinimizesInrushCurrent
?TDFN34-16LowProfilePackage
?-40℃to+85℃TemperatureRange
AAT1451应用:
?Monitors
?NotebookandNetbookComputers
?PortableDVDPlayers
?PortableTV
?WhiteLEDBacklight
图***1451方框图
图***1451典型应用电路图
图***1451评估板电路图
AAT1451评估板材料清单:
AAT1451评估板表面安装电感:
AAT1451评估板表面安装电容:
图***1451评估板PCB布局图
，
目前在一般的LED照明市场上，该电流检测电路基于一个设计旨在饱和区域运行的有源电流镜。该器件根据电流阱两端的压降将自动在线性降压模式和具有最低250mV检测电压的电感升压模式之间转换。
这种架构的优势在于在所有的LED电流和电池电压条件下其效率都非常高，那么PN结半导体器件在正向导通后，对其进行了简要的分析，ZMDI公司的Zled7330LED驱动器的电源效率达到98%,主要为高亮和大电流LED而设计.ZLED7330具有三种模式来决定输出电平,输出电流高达1.2A,内部集成了40V功率开关,DC输入电压从8.5V到40V,输出电流精度5%,LED开路保护和热关断保护.本文介绍了ZLED7330主要特性和优势,以及几种基本应用电路.
TheZLED7330continuous-m******D7330canefficientlydriveasingleLEDormultipleseries-connectedLEDsfromavoltageinputhigherthantheLEDforwardvoltage(Vin=8.5to40VDC).Itprovidesanadjustableoutputcurrent(1.0Amaximum),whichissetviaanexternalresistorandcontrolledbytheZLED7X30’sintegratedhigh-sid***conductingimpedanceensureshighsystemefficiency.
***ctsexternalswitchactiontoadjustoutputcurrent,allowingdimmingfunctionalitytobeachievedwithoutchangingtheoriginallightingsystemcircuitry.
Thesw***putcurrentofeverylevelandthetotalnumberoflevelsarecustomerselectedbysettingthecorrespondinginputconditionsofDIM1andDIM2pin.
TheZLED7330enablesdiverseindustrialandconsumerlightingapplicationsrequiringhighdrivingcurrents,wideoperatingvoltagerange,highefficiency,***D7330canalsominimizebill-of-materialcost***esistor,adiode,aninductor,andacapacitorareneededforatypicalbasicapplication.
ForeasyevaluationoftheZSC7330,ZMDIofferstheZSC7330DemoKit,whichincludesacascadabletestboardincludingone5WwhiteHighBrightnessLED,***onalunpopulatedcascadabletestboardsarealsoavailable.
ZLED7330主要特性:
Switchdimmingwithmultiplelevels
Threemodesforoutputlevelsettings
Upto1.2Aoutputcurrent
Internal40Vpowerswitch
WideDCinputvoltagerange8.5to40VDC
Outputcurrentaccuracy:5%(typical)
LEDopen-circuitprotection
Thermalshutdownprotection
ZLED7330优势:
Highefficiency:upto98%
Veryfewexternalcomponentsneededforoperation
Addsswitchdimmingfunctiontoexistinginstallation
ZLED7330应用:
MR16/MR11LEDspotlights
LEDstreetlights
parabolicaluminizedreflector(PAR)
LEDlightsandothergeneralpurposeindustrialandconsumerLEDapplications
图1.开关调光的ZLED7330应用电路
图2.输出电流由RS决定的ZLED7330基本应用电路
图3.采用卤钨灯电子变压器的ZLED7330应用电路
，既不需要匹配LED，。