Powerint公司的4.2WLED驱动方案是采用LNK605DG器件,输入电压为85–265VAC,输出电压为12V/350mA.4.2WLED驱动方案初级采用恒压/恒流(CV/CC)控制器,从而省略了次级控制和光耦.输出电压精度±5%,输出电流精度±10%,包括火线电压,负载和温度补偿和元件误差.主要应用手机,无绳电话,PDA,MP3的充电器,适配器,LED驱动器等.本文介绍了LNK605DG的主要特性,应用案例和4.2WLED驱动方案设计电路图,PCB布局(61mmx24mm)与材料清单.
Energy-Efficient,AccurateCV/CCSwitcher4.2WLED驱动器指标:85–265VACInput;12V,350mAOutputThisengineeringreportdescribesthedesignforauniversalinput,12V,350mACV/CCpowersupplyforLEDdriverapplications.ThispowersupplyutilizestheLNK605DGdevicefromthePowerIntegrationsLinkSwitch-IIfamily.
Thisdocumentcontainsthepowersupplyandtransformerspecifications,schematics,billofmaterials,andtypicalperformancecharacteristicspertainingtothispowersupply.
4.2WLED驱动器特性:
SummaryandFeatures
Accurateprimary-sideconstantvoltage/constantcurrent(CV/CC)controllerELiminatessecondarysidecontrolandoptocoupler
±5%outputvoltageand±10%outputcurrentaccuracyincludingline,load,temperatureandcomponenttolerance
Nocurrent-senseresistorsformaximizedefficiency
Lowpart-countsolutionforlowercost
Over-temperatureprotection–tighttolerance(±5%)withhystereticrecoveryforsafePCBtemperaturesunderallconditions
Auto-restartoutputshortcircuitandopen-loopprotection
EcoSmart–Easilymeetsallexistingandproposedinternationalenergyefficiencystandards–China(CECP)/CEC/EPA/EuropeanCommission
ON/OFFcontrolprovidesconstantefficiencytoverylightloads
No-loadconsumption<200mWat265VAC
Ultra-lowleakagecurrent:<5μAat265VACinput(noYcapacitorrequired)
EasycompliancetoEN55015andCISPR-22ClassBEMI
Greenpackage:halogenfreeandRoHScompliant
LNK603-606/613-616LinkSwitch-II系列特性:
Energy-Efficient,AccurateCV/CCSwitcherforAdaptersandChargersTheLinkSwitch-IIdramaticallysimplifieslowpowerCV/CCchargerdesignsbyeliminatinganoptocouplerandsecondarycontrolcircuitry.Thedeviceintroducesarevolutionarycontroltechniquetoprovideverytightoutputvoltageandcurrentregulation,compensatingfortransformerandinternalparametertolerancesalongwithinputvoltagevariations.
Thedeviceincorporatesa700VpowerMOSFET,anovelOn/Offcontrolstatemachine,ahighvoltageswitchedcurrentsourceforselfbiasing,frequencyjittering,cycle-by-cyclecurrentlimitandhystereticthermalshutdowncircuitryontoamonolithicIC.
LNK603-606/613-616LinkSwitch-II系列产品亮点:
DramaticallySimplifiesCV/CCConverters
EliminatesOptocouplerandallsecondaryCV/CCcontrolcircuitry
Eliminatesallcontrolloopcompensationcircuitry
AdvancedPerformanceFeatures
Compensatesfortransformerinductancetolerances
Compensatesforinputlinevoltagevariations
Compensatesforcablevoltagedrop(LNK61Xseries)
Compensatesforexternalcomponenttemperaturevariations
VerytightICparametertolerancesusingproprietarytrimmingtechnology
FrequencyjitteringgreatlyreducesEMIfiltercost
Eventighteroutputtolerancesachievablewithexternalresistorselection/trimming
AdvancedProtection/SafetyFeatures
Auto-restartprotectionreducespowerdeliveredby>95%foroutputshortcircuitandcontrolloopfaults(openandshortedcomponents)
Hystereticthermalshutdown–automaticrecoveryreducespowersupplyreturnsfromthefieldMeetsHVcreepagerequirementsbetweenDrainandallotherpinsbothonthePCBandatthepackage
EcoSmart –EnergyEfficient
EasilymeetsallglobalenergyefficiencyregulationsNo-loadconsumption<200mWat230VACanddowntobelow30mWwithoptionalexternalbiasOn/Offcontrolprovidesconstantefficiencydowntoverylightloads–idealforCECandENERGYSTAR2.0regulationsNocurrentsenseresistors–maximizesefficiency
GreenPackage
HalogenfreeandRoHScompliantpackage
Applications
Chargersforcell/cordlessphones,PDAs,MP3/portableaudiodevices,adapters,LEDdrivers,etc.
图1.LNK603-606/613-616LinkSwitch-II系列方框图
图2.4.2WLED驱动器电路图
图2.4.2WLED驱动器PCB布局(61mmx24mm).
材料清单(BOM):
详情请见PDF文档PowerintLNK605DG4.2WLED驱动方案.rar
来源：Powerint
，设计人员也应该尽可能地避免使用电解电容。
LED灯闪烁的常见原因与处理办法
通常人眼能够感知到频率达70Hz的光闪烁，所有的LED都是在恒流驱动时性能最佳。以
发光二极管和普通二极管一样是一种用半导体材料制作的P/N结器件,除了能发光之外,其他特性和普通二极管相似。发光二极管主要有两个特点：
①单向导电性。发光二极管和普通二极管一样具有单向导电的特性,即在发光二极管的正极加正电压,负极加负电压时发光二极管导通发光,相反则不导通也就不能发光。这就决定了发光管必须使用直流电源或者单向脉动电源供电;
②发光二极管有负温度系数的势垒电势。发光二极管上施加的正向电压低于某个电压值时发光二极管不导电,但外加电压一旦超过这一电压值时发光二极管的电流就会随着外加电压的变化急剧增加,对外电路呈现很低的动态电阻,这一电压值就是发光二极管的势垒电势,不同颜色的发光管其势垒电势不同。
2LED的直流驱动和脉冲驱动选择
发光管发光靠电能激发,不管是直流驱动还是脉冲驱动,输入的电能量决定了输出的光能量,脉冲驱动不可能使发光管提高光效,相反,应该是直流驱动光效更高。因为发光管的输入电流过大光通量随电流增加的速度将变缓,发光管的管小降低。另外,过大的电流还会引起发光管发射的光谱向长波方向偏移,对于白光发光管来说,这将导致激发荧光粉效能的降低,使光效下降。所以,脉冲驱动不可能使发光管省电,但设计合理的脉冲驱动器也不会明显的引起光效的下降,因此也就不会比直流驱动更明显的费电。但是脉冲驱动器常常具有电路结构简单生产成本低的特点,所以还是值得使用。因此,究竟用脉冲驱动还是用直流驱动要根据具体情况而定。如果用脉冲驱动发光管,一般不会缩短发光管的使用寿命发光管是一种量子器件适合高速工作,这正是发光管的优点之一。如果有闪烁使用的发光管频频损坏,那应该是其他方面的原因引起的电流过大等等,而不会是发光管自身不耐闪烁。一般的驱动技术不但受输入电压范围的限制,而且效率低.在用于低功率的普通LED驱动时,由于电流只有几个MA,因此损耗不明显当用作电流有几百MA甚至更高的高亮LED的驱动时,功率电路的损耗就成了比较严重的问题。
3主电路结构设计
3.1开关电源的应用与发展
以高频变压器取代工频变压器,采用脉冲调制技术的直流一直流变换器型稳压电源,通常称为开关电源。它具有管耗小、效率高、稳压范围宽及体积小、重量轻等特点,目前已在各种电子仪器和设备、航空和宇宙飞行器、发射机、电子计算机、通讯设备和电视机、录放机中得到了应用。开关晶体管、开关二极管和开关变压器是组成开关电源的三个关键元件,减小开关电源的体积和重量就须提高电源的开关频率,大功率,高反压和高速开关晶体管,快速恢复开关二极管以及开关电源变压器中使用的高频,低损耗磁性材料的技术发展,使开关电源的开关频率从数十kHz发展到数百kHz。开关电源的基本电路由“交流一直流转换电路”、“开关型功率变换器”、“控制电路”和“整流滤波电路”等组成(见图1)。输入的电网电压通过“交流一直流转换电路"中的整流器和滤波器转换成直流电,该直流电源作为“开关型功率变换器"的输入电源,经过“开关型功率变换器”将直流电转变为高频脉冲方波电压输给“整流滤波电路”,变成平滑直流供给负载,控制电路则起着控制“开关型功率变换器”工作的作用。
开关型功率变换器是开关电源的主电路,开关电源的能量转换,电压变换就由它来承担。在直流变换器的基础上,由于高频脉冲技术及开关变换技术的进一步发展,出现了推挽式开关型功率变换器,全桥式功率变换器,半桥式功率变换器,单端正激式功率变换器,单端反激式功率变换器,快速磁放大器式开关型功率变换器等。其控制方式可分为脉冲宽度调制(PWM)和脉冲频率调制(PFM)两种。
3.2功率开关原件设计
开关电源中的功率开关元件主要是功率晶体管、功率MOSFET、功率IGBT。本设计中选功率三极管E13007,
同时配上散热片。开关频率定为40kHz。
3.3高频变压器的分布参数
开关变压器传递的是高频方波电压,在瞬变过程中,漏感和分布电容会引起浪涌电流和尖峰电压及脉冲顶部震荡,造成损耗增加,严重会造成开关管损坏,因此应加以控制。在输出为高压,输出绕组匝数多,层数多时应考虑电容带来的危害,一般的设计主要考虑漏感的影响。同时,降低分布电容有利于抑制高频信号对负载的干扰。一般根据开关电源电路的要求提出漏感和分布电容限定值,在变压器的线圈结构中实现,而趋肤效应影响则作为选择导线规格的条件之一。变压器的漏感主要为励磁电感,、原边漏感、副边漏感：,如图3.14所示。其中励磁电感LM很大,并且与原边绕阻并联,因此可以忽略。副边的漏感：折合到原边,和原边的漏感和为变压器的等效漏感。
任何金属件之间都有电容存在,如果这两金属件之间电位处处相等,这样形成的电容成为静电容。在变压器中,绕组线匝之间,同一绕组上下层之间,不同绕组之间,绕组对屏蔽层之间沿着某一线长度方向的电位是变化的,这样形成的电容就不同于静电容,成为分布电容。变压器分布电容由以下部分组成：原副边绕阻之间电容C,原副边绕阻各层之间电容C、C,原副边各匝间及对铁芯或屏蔽层的电容。开关电源变压器通常每层绕组有较多匝数,每层匝间总电容为每匝电容串联,远小于层间电容,故匝间电容,可忽略不计。折合到原边后则比：大的多因此C,和C2可以忽略。在各分布电容中C,起着主导作用,将其折合到原边用CP表示。因此得到简化后的变压器的等效电路图,如图2所示。
它由等效漏感、等效电容C,和理想变压器组成。减小漏感可采用一下措施：①减小绕组匝数,应采用高饱和磁感应强度,低损耗的磁性材料;②减少绕组厚度,增加绕组高度;④尽可能减少绕组间绝缘厚度;④初、次级绕组采用分层交叉绕制;⑤对于环形磁性变压器,不管初次级匝数多少均应沿环形圆周均匀分布。当次级绕组匝数很少时,宜采用多个绕组并联的方法;⑥初、次级绕组双线并绕。
3.4导线材料及绝缘问题
3.4.1导电材料选用
电子变压器用导电材料包括绕组用导线和引出线两部分。电子变压器使用铜导线。导线的特性取决于外包或外涂的绝缘材料的特性。因此,电子变压器在选用绕组线和引出线时,选择导线的主要依据是导线的绝缘材料性能。由此可见,导线的绝缘材料性能决定了导线的应用性能。选择导线材料时,要考虑以下几点：
(1)工作温度,绕组线和引出线有不同的使用温度,应按变压器的最高工作温度来选择符合要求的导电材料。
(2)工作电流,这是选择导线直径的基本依据。
(3)工作频率,在高频下由于集肤效应和邻近效应的影响使导线的损耗电阻增加,选择导线必须考虑减小这种影响。
(4)导线直径小于两倍穿透深度。当导线要求的线径大于由穿透深度决定的最大有效直径时,应采用小直径的导线并绕或采用多股导线。大电流绕组最好能采用宽而薄的扁铜带,铜带厚度应小于穿透深度的两倍。
3.4.2绝缘问题
绝缘材料是电子变压器的重要材料之一,电子变压器的使用寿命和可靠性等在很大程度上取决于变压器的绝缘系统和所使用的绝缘材料的性能。高压变压器的绝缘包括高压边对原边的绝缘、高压边对铁心的绝缘、高压边端部的绝缘。提高绝缘一个困难在于高频变压器的体积较小,绝缘距离受到限制;另一个困难在于提高绝缘强度和降低漏感是一对矛盾,提高绝缘强度要求高压边对原边及对铁心的距离越近越好。同时,为了降低变压器的分布电容,绝缘材料的介电常数一定要小。选择绝缘材料时,以下几点必须考虑：①耐热性,应按电子变压器的最高工作温度选择具有相应耐热等级的绝缘材料;②防水性,工作在湿热环境下的电子变压器应选择防水性优良的绝缘材料;③耐电晕性,高压变压器要求绝缘材料有良好的耐电晕性;④电绝缘性,包括击穿电压、介电性能、体积电阻、表面电阻、介质损耗等。应按变压器绝缘系统的要求选择相应的绝缘材料。
4结语
发光二极管作为一种新型照明光源正在获得越来越广泛的应用。半导体照明(semi-conductorlighting)是未来照明领域重要的发展方向,半导体照明与一般光伏电源配用的节能灯泡相比具有节能、长寿、安全、环保、色彩丰富、体积小、耐闪烁、可靠性高、调控方便等诸多优点。
，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-modeinductivestep-downconverterfamilyisoneofourZLEDLEDcontrolICs.Itisdesignedforapplicationsrequiringhighbrightnessandhighcurrent.TheZLED7330canefficientlydriveasingleLEDormultipleseries-connectedLEDsfromavoltageinputhigherthantheLEDforwardvoltage(Vin=8.5to40VDC).Itprovidesanadjustableoutputcurrent(1.0Amaximum),whichissetviaanexternalresistorandcontrolledbytheZLED7X30’sintegratedhigh-sideoutputcurrent-sensingcircuitandhighspeedinternal40Vpowerswitch.Itslowconductingimpedanceensureshighsystemefficiency.
TheZLED7330providesaswitchdimmingfunction.Itdetectsexternalswitchactiontoadjustoutputcurrent,allowingdimmingfunctionalitytobeachievedwithoutchangingtheoriginallightingsystemcircuitry.
Theswitchdimmingisimplementedineithertwo-levEL-modeorthree-levelmode.TheoutputcurrentofeverylevelandthetotalnumberoflevelsarecustomerselectedbysettingthecorrespondinginputconditionsofDIM1andDIM2pin.
TheZLED7330enablesdiverseindustrialandconsumerlightingapplicationsrequiringhighdrivingcurrents,wideoperatingvoltagerange,highefficiency,andvariablebrightnesscontrol.Itoffersover-temperatureandLEDopen-circuitprotection.TheZLED7330canalsominimizebill-of-materialcostsbecauseveryfewexternalcomponentsarerequiredformostapplications.Onlyaresistor,adiode,aninductor,andacapacitorareneededforatypicalbasicapplication.
ForeasyevaluationoftheZSC7330,ZMDIofferstheZSC7330DemoKit,whichincludesacascadabletestboardincludingone5WwhiteHighBrightnessLED,5ZLED7330samplesinSOP-8packageanddocumentation.OrderusingpartnumberZLED7330KIT-D1.Additionalunpopulatedcascadabletestboardsarealsoavailable.
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
，应先测定负载电流的准确值，
Teridian公司的78M6618是高度集成的独立监测八路单相AC出口能量的IC,集成了多个主机接口,LCD驱动器和可配置的I/O口.78M6618提供用于和电压与电流传感器接口的十个模拟输入端,并具有21位dELta-sigmaADC,独立的32位计算引擎(CE),数字温度补偿以及精密的电压基准源,能在2000:1动态范围内提供优于0.5%的精度,非常适合用在嵌入式高精度AC功率和能量的测量.本文介绍了78M6618主要特性,功能方框图以及其中的AFE方框图,MPU/CE通信方框图和78M6618应用方框图.
78M6618OctalPowerandEnergyMeasurementIC
TheTeridian78M6618isahighlyintegratedICforindependentmonitoringandmeasurementofuptoeight(8)single-phaseACoutlets.Withmultiplehostinterfaceoptions,anintegratedLCDdriver,andconfigurableI/Os,itisidealformeteredpowerdistributionunits(PDUs)andrackenclosuresforthedatacenteraswellasintelligentpowerstripsandsubpanelsinthegrid-friendlydigitalhome.
Atthemeasurementinterface,thedeviceprovidestenanaloginputsforinterfacingtovoltageandcurrentsensors.VoltagesfromthesensorsarefedtoTeridian’spatentedSingleConverterTechnology?whichusesa21-bitdelta-sigmaADC,independent32-bitcomputeengine(CE),digitaltemperaturecompensation,andprecisionvoltagereferencestoprovidebetterthan0.5%accuracyoverawide2000:1dynamicrange.
TheintegratedMPUcoreand128KBofFlashmemoryprovidesaflexiblemeansofconfiguration,post-processing,dataformatting,interfacingtohostprocessorviaaUARTorSPIinterface,displayingoutputdatatoanLCD,orusingDIOpinsforintelligentrelaycontrol.CompletefirmwareforcommonapplicationsisavailablefromTeridianandcanbepre-loadedintotheICduringmanufacturingtest.Alternatively,acompletearrayofICE,developmenttoolsandprogramminglibrariesareavailabletoallowcustomizationMPUcodeforeachapplication.
Teridian’snewfamilyof78M661xenergymeasurementsolutionsaretheidealchoiceforembeddinghighaccurateACpowerandenergymeasurementintogridfriendlyelectronicequipmentandintelligentpowerdistributiongear.
78M6618主要特性:
?<0.5%Whaccuracyoverwide2000:1currentrangeandovertemperature
?ExceedsIEC62053/ANSIC12.20standards
?Voltagereference<40ppm/℃
?Tensensorinputs—V3P3referenced
?21-bitdelta-sigmaADCwithindependent32-bitcomputeengine(CE)
?8-bitMPU(80515),1clockcycleperinstructionwith4KBMPUXRAM
?128KBFlashwithsecurity
?IntegratedICEforMPUdebug
?32kHztimebasewithhardwarewatchdogtimer
?UARTandhigh-speedslaveSPIhostinterfaceoptions
?Upto19generalpurpose5VtolerantI/Opins
?LCDdriver(upto70pixels)
?PackagedinaRoHScompliant(6/6)lead-free68-pinQFN
?CompleteApplicationFirmwareprovides:oTrueRMScalculationsforcurrent,voltage,linefrequency,realpower,reactivepower,apparentpower,andpowerfactor
Accumulatedwatt-hours,kilowatt-hours,andcost
Intelligentswitchcontrolatzerocrossings
Digitaltemperaturecompensation
Phasecompensation(±15°)
Quickcalibrationroutines
46-64Hzlinefrequencyrangewithsamecalibration
图1.78M6618功能方框图
The78M6618includes:
?Aten-inputanalogfrontend(AFE)
?Anindependentdigitalcomputationengine(CE)
?An8051-compatiblemicroprocessor(MPU)whichexecutesoneinstructionperclockcycle(80515)
?Aprecisionvoltagereference
?Atemperaturesensor
?LCDdrivers
?RAMandFlashmemory
?AvarietyofI/Opins
图2.78M6618AFE方框图
图3.78M6618MPU/CE通信方框图
图4.78M6618应用方框图
78M6618评估板
The78M6618evaluationboardisadesignexampleofaswitched8-outletpowerdistributionunitwithperoutletmetering.Theboardincludesone78M6618IC,anAC-DCpowersupply,oneACinput,eightswitchedoutputs(relays),andconnectorstotheserialinterfacesandDIOpins.
图5.78M6618评估板外形图
详情请见:
http://www.teridian.com/products/6618.php
Powerint公司的4.2WLED驱动方案是采用LNK605DG器件,输入电压为85–265VAC,输出电压为12V/350mA.4.2WLED驱动方案初级采用恒压/恒流(CV/CC)控制器,从而省略了次级控制和光耦.输出电压精度±5%,输出电流精度±10%,包括火线电压,负载和温度补偿和元件误差.主要应用手机,无绳电话,PDA,MP3的充电器,适配器,LED驱动器等.本文介绍了LNK605DG的主要特性,应用案例和4.2WLED驱动方案设计电路图,PCB布局(61mmx24mm)与材料清单.
Energy-Efficient,AccurateCV/CCSwitcher4.2WLED驱动器指标:85–265VACInput;12V,350mAOutputThisengineeringreportdescribesthedesignforauniversalinput,12V,350mACV/CCpowersupplyforLEDdriverapplications.ThispowersupplyutilizestheLNK605DGdevicefromthePowerIntegrationsLinkSwitch-IIfamily.
Thisdocumentcontainsthepowersupplyandtransformerspecifications,schematics,billofmaterials,andtypicalperformancecharacteristicspertainingtothispowersupply.
4.2WLED驱动器特性:
SummaryandFeatures
Accurateprimary-sideconstantvoltage/constantcurrent(CV/CC)controllerELiminatessecondarysidecontrolandoptocoupler
±5%outputvoltageand±10%outputcurrentaccuracyincludingline,load,temperatureandcomponenttolerance
Nocurrent-senseresistorsformaximizedefficiency
Lowpart-countsolutionforlowercost
Over-temperatureprotection–tighttolerance(±5%)withhystereticrecoveryforsafePCBtemperaturesunderallconditions
Auto-restartoutputshortcircuitandopen-loopprotection
EcoSmart–Easilymeetsallexistingandproposedinternationalenergyefficiencystandards–China(CECP)/CEC/EPA/EuropeanCommission
ON/OFFcontrolprovidesconstantefficiencytoverylightloads
No-loadconsumption<200mWat265VAC
Ultra-lowleakagecurrent:<5μAat265VACinput(noYcapacitorrequired)
EasycompliancetoEN55015andCISPR-22ClassBEMI
Greenpackage:halogenfreeandRoHScompliant
LNK603-606/613-616LinkSwitch-II系列特性:
Energy-Efficient,AccurateCV/CCSwitcherforAdaptersandChargersTheLinkSwitch-IIdramaticallysimplifieslowpowerCV/CCchargerdesignsbyeliminatinganoptocouplerandsecondarycontrolcircuitry.Thedeviceintroducesarevolutionarycontroltechniquetoprovideverytightoutputvoltageandcurrentregulation,compensatingfortransformerandinternalparametertolerancesalongwithinputvoltagevariations.
Thedeviceincorporatesa700VpowerMOSFET,anovelOn/Offcontrolstatemachine,ahighvoltageswitchedcurrentsourceforselfbiasing,frequencyjittering,cycle-by-cyclecurrentlimitandhystereticthermalshutdowncircuitryontoamonolithicIC.
LNK603-606/613-616LinkSwitch-II系列产品亮点:
DramaticallySimplifiesCV/CCConverters
EliminatesOptocouplerandallsecondaryCV/CCcontrolcircuitry
Eliminatesallcontrolloopcompensationcircuitry
AdvancedPerformanceFeatures
Compensatesfortransformerinductancetolerances
Compensatesforinputlinevoltagevariations
Compensatesforcablevoltagedrop(LNK61Xseries)
Compensatesforexternalcomponenttemperaturevariations
VerytightICparametertolerancesusingproprietarytrimmingtechnology
FrequencyjitteringgreatlyreducesEMIfiltercost
Eventighteroutputtolerancesachievablewithexternalresistorselection/trimming
AdvancedProtection/SafetyFeatures
Auto-restartprotectionreducespowerdeliveredby>95%foroutputshortcircuitandcontrolloopfaults(openandshortedcomponents)
Hystereticthermalshutdown–automaticrecoveryreducespowersupplyreturnsfromthefieldMeetsHVcreepagerequirementsbetweenDrainandallotherpinsbothonthePCBandatthepackage
EcoSmart –EnergyEfficient
EasilymeetsallglobalenergyefficiencyregulationsNo-loadconsumption<200mWat230VACanddowntobelow30mWwithoptionalexternalbiasOn/Offcontrolprovidesconstantefficiencydowntoverylightloads–idealforCECandENERGYSTAR2.0regulationsNocurrentsenseresistors–maximizesefficiency
GreenPackage
HalogenfreeandRoHScompliantpackage
Applications
Chargersforcell/cordlessphones,PDAs,MP3/portableaudiodevices,adapters,LEDdrivers,etc.
图1.LNK603-606/613-616LinkSwitch-II系列方框图
图2.4.2WLED驱动器电路图
图2.4.2WLED驱动器PCB布局(61mmx24mm).
材料清单(BOM):
详情请见PDF文档PowerintLNK605DG4.2WLED驱动方案.rar
来源：Powerint
，LED调光电源。 恒流源的输出电压纹波变为10mA*310Ω=3.1V，并为现有应用的升级提供便利。
Molex的LED数组灯座使用双头集线端子(double-endedwire)，Prema公司的PR4101是大功率LED降压驱动器,能串通方式驱动一个或多个大功率led.工作电压可高达40V,采用外接N沟MOSFET开关管,输出电流可高达1A.可用于卤素灯,通用照明,告警照明,汽车照明,信号指示和LCD背景光.本文介绍了PR4101的主要特性,方框图,典型应用电路,以及采用12/24V电源,12VDC和12VAC电源的PR4101各种应用电路.
HighPowerLEDBuckDriverPR4101
ThePR4101isaLEDbuckdriverfordrivingoneorseveralhighpowerLEDsinseries.
Thesupplyvoltagecanbeupto40V,withanoutputcurrentofmorethan1Ausingan
externalN-channELMOSFETswitchingtransistor.ThePR4101AwithadditionalPWMand
powerdowninputisdeliveredSOP14packaged,whilethePR4101BisofferedSO8
packaged.
PR4101主要特性:
Adjustableoutputcurrentof1Aandmore
Supplyvoltageupto40VbulbreplacementbyLEDs
Dimmingwithphase-cutdimmer
BrightnesscontrolwithPWM(PR4101Aonly)
Outputcurrenttemperaturecompensation
Delayedstartpossible(PR4101Aonly)
Overtemperatureprotection
FrequencyspreadingforimprovedEMI
Lowstandbycurrentof<35μA
Undervoltagelockout
应用:
Halogenlamporfilament
Generalillumination
Warninglights
Automotivelighting
Indicatorsigns
LCDbacklighting
图1.PR4101典型应用电路
图2.PR4101方框图
图3.采用PR4101的12/24V电源的PR4101应用电路
图4.采用12VDC的PR4101应用电路图
图5.采用12VAC的PR4101应用电路
图6.PR4101显示板电路图
详情请见:
http://www.prema.com/pdf/pr4101.pdf，在全桥堆之后，中艾电源LED调光电源增加连接选项并降低成本。其免焊旋紧式(screwdown)连接可以实现标准化的制造过程， ZMDI公司的Zled7022是六路低噪音恒定频率电荷泵DC/DC转换器,可驱动六路LED,每路LED的电流从1.8mA到20mA可编程,并联工作时可驱动更大电流的LED,工作电压2.8V-5.5V,关断模式电流小于2uA,主要用在手提设备的LED背光,手机,智能手机和PDA的LED照明,数码相框照明等.本文介绍了ZLED7022主要特性和`优势,方框图以及典型应用电路.
TheZLED7022,oneofourZLEDfamilyofLEDcontrolICs,isalow-noise,constant-frequencychargepumpDC/DCconverterthatcandriveuptosixLEDchannELs,providingaprogrammableconstantcurrentlevelrangingfrom1.8mAto20mAperLEDchannel.ItcanalsodrivehighercurrentLEDsbecauseitscurrentsinkscanoperateinparallel.ItenableswhiteorothercolorLEDapplicationsthatrequireuniformintensityand/orlinearprogressionsinbrightness.CapableofoperatingefficientlywithDCvoltagesuppliesrangingfrom2.8Vto5.5V,itisidealforsmall,battery-poweredapplicationsbecauseveryfewexternalcomponentsareneeded:typicallyonesmall-dimension1μFcapacitoracrosstheC+andC-pinsandtwosmall-dimension2.2μFcapaci-torstoGNDfromtheVCCandVoutpins.
TheZLED7022’sPulseCountControl(PCC)serialdigi-talinputisusedtoenable/disabletheLEDsandsetthecurrentlevel(14settingsusinganearlylogarithmicscaletoprovidealinearbrightnessprogression).Thissimple,high-speedinterfaceallowsefficientreal-timemanagementofLEDsviamicrocontrollersorcontrolsystems.
TheZLED7022’sfeaturesincludeintegratedsoft-startcircuitrytoprotectagainstexcessivein-rushcurrentduringpower-onandalow-currentshutdownmodethatreducesquiescentcurrentconsumptiontoapproximately1μA(typical)bydisconnectingtheloadfromtheinputwhentheEN/SETpinislowforaspecifiedtime.
ZLED7022主要特性:
Lowquiescentcurrentinlow-currentshutdownmode:1μAtypical;<2μAmaximum
IntegratedthermalshutdownprotectionpreventsdamagebyshuttingdowntheZLED7022ifthediejunctiontemperatureexceeds160℃(typical)
Fixedchargepumpswitchingfrequency:1MHz(typ.)
Soft-startfeatureprotectsagainstexcessiveinrushcurrentduringpower-on
ZLED7022优势:
Currentmatchingaccuracy:±0.9%(typical)
One-pinon/offorbrightnesscontrolforuptosixLEDsviaasimplePCCserialinterface—nopulse-widthmodulationoradditionalcontrolcircuitneeded
14programmablecurrentlevelsforachievingreal-timecontrolofeffectssuchasLEDfade-outorsuddenchangesinbrightness
LowEMIandback-injectednoisebecausethechargepumpisnotinductor-based
Veryfewexternalcomponentsneededforoperation
FlexibledesignenablesdiverseLEDapplications:upto20mAperchannel
LEDdriverfamilyconceptwithlow-voltagefour-channelLEDdriverZLED7012
ZLED7022典型应用:
LEDbacklightingforportabledevices
LEDlightingforcellphones,smartphones.PDAs
Illuminationofdigitalphotoframes
BacklightingforGPS/navigationsystems
LowvoltageLEDlightingfixtures
Generalpurposelow-voltageindustrialandconsumerapplications
图1.ZLED7022方框图
图2.ZLED7022应用电路
图3.ZLED7022采用D4:D0的基本应用电路
，
NXP公司的PCA9626是I2C总线控制的24位LED驱动器,每个LED输出有它本身的8位分辨率的固定频率PWM控制器,工作频率97kHz,占空比从0%到99.6%可调整,使LED能设定到所需亮度.PCA9626工作电压从2.3V到5.5V,100mA漏极开路输出使电压高达40V,内部25MHz振荡器不需要外接元件.本文介绍了PCA9626的主要特性,方框图以及典型应用.
PCA9626
24-bitFm+I2C-bus100mA40VLEDdriver
ThePCA9626isanI2C-buscontrolled24-bitLEDdriveroptimizedforvoltageswitchdimmingandblinking100mARed/Green/Blue/Amber(RGBA)LEDs.EachLEDoutputhasitsown8-bitresolution(256steps)fixedfrequencyindividualPWMcontrollerthatoperatesat97kHzwithadutycyclethatisadjustablefrom0%to99.6%toallowtheLEDtobesettoaspecificbrightnessvalue.Anadditional8-bitresolution(256steps)groupPWMcontrollerhasbothafixedfrequencyof190Hzandanadjustablefrequencybetween24Hztoonceevery10.73secondswithadutycyclethatisadjustablefrom0%to99.6%thatisusedtoeitherdimorblinkallLEDswiththesamevalue.
EachLEDoutputcanbeoff,on(noPWMcontrol),setatitsindividualPWMcontrollervalueoratbothindividualandgroupPWMcontrollervalues.ThePCA9626operateswithasupplyvoltagerangeof2.3Vto5.5Vandthe100mAopen-drainoutputsallowvoltagesupto40V.
ThePCA9626isoneofthefirstLEDcontrollerdevicesinanewFast-modePlus(Fm+)family.Fm+devicesofferhigherfrequency(upto1MHz)andmoredensELypopulatedbusoperation(upto4000pF).
TheactiveLOWOutputEnableinputpin(OE)blinksalltheLEDoutputsandcanbeusedtoexternallyPWMtheoutputs,whichisusefulwhenmultipledevicesneedtobedimmedorblinkedtogetherwithoutusingsoftwarecontrol.
SoftwareprogrammableLEDGroupandthreeSubCallI2C-busaddressesallowallordefinedgroupsofPCA9626devicestorespondtoacommonI2C-busaddress,allowingforexample,allredLEDstobeturnedonoroffatthesametimeormarqueechasingeffect,thusminimizingI2C-buscommands.Sevenhardwareaddresspinsallowupto126devicesonthesamebus.
TheSoftwareReset(SWRST)CallallowsthemastertoperformaresetofthePCA9626throughtheI2C-bus,identicaltothePower-OnReset(POR)thatinitializestheregisterstotheirdefaultstatecausingtheoutputNANDFETstobeOFF(LEDoff).Thisallowsaneasyandquickwaytoreconfigurealldeviceregisterstothesamecondition.
InadditiontothesefeaturesfoundinPCA9633,PCA9634,PCA9635,PCA9622andPCA9624,anewfeaturetocontrolLEDoutputpatternisincorporatedinthePCA9626.Anewcontrolbytecalled‘ChaseByte’allowsenablingordisablingofselectiveLEDoutputsdependingonthevalueoftheChaseByte.ThisfeaturegreatlyreducesthenumberofbytestobesenttothePCA9626whenrepetitivepatternsneedtobedisplayedasincreatingamarqueechasingeffect.
IfthePCA9626on-chip100mANANDFETsdonotprovideenoughcurrentorvoltagetodrivetheLEDs,thenthePCA9635andthePCA9635withlargercurrentorhighervoltageexternaldriverscanbeused.
PCA9626主要特性:
24LEDdrivers.Eachoutputprogrammableat:
Off
On
ProgrammableLEDbrightness
Programmablegroupdimming/blinkingmixedwithindividualLEDbrightness
1MHzFast-modePluscompatibleI2C-businterfacewith30mAhighdrivecapabilityonSDAoutputfordrivinghighcapacitivebuses
256-step(8-bit)linearprogrammablebrightnessperLEDoutputvaryingfromfullyoff(default)tomaximumbrightnessusinga97kHzPWMsignal
256-stepgroupbrightnesscontrolallowsgeneraldimming(usinga190HzPWMsignal)fromfullyofftomaximumbrightness(default)
256-stepgroupblinkingwithfrequencyprogrammablefrom24Hzto10.73sanddutycyclefrom0%to99.6%
24open-drainoutputscansinkbetween0mAto100mAandaretoleranttoamaximumoffstatevoltageof40V.Noinputfunction.
OutputstatechangeprogrammableontheAcknowledgeortheSTOPCommandtoupdateoutputsbyte-by-byteorallatthesametime(defaultto‘ChangeonSTOP’).
ActiveLOWOutputEnable(OE)inputpinallowsforhardwareblinkinganddimmingoftheLEDs
7hardwareaddresspinsallow126PCA9626devicestobeconnectedtothesameI2C-busandtobeindividuallyprogrammed
4softwareprogrammableI2C-busaddresses(oneLEDGroupCalladdressandthreeLEDSubCalladdresses)allowgroupsofdevicestobeaddressedatthesametimeinanycombination(forexample,oneregisterusedfor‘AllCall’sothatallthePCA9626sontheI2C-buscanbeaddressedatthesametimeandthesecondregisterusedforthreedifferentaddressessothat3ofalldevicesonthebuscanbeaddressedatthesametimeinagroup).SoftwareenableanddisableforI2C-busaddress.
AChaseByteallowsexecutionofpredefinedON/OFFpatternforthe24LEDoutputs
SoftwareResetfeature(SWRSTCall)allowsthedevicetoberesetthroughtheI2C-bus
25MHzinternaloscillatorrequiresnoexternalcomponents
Internalpower-onreset
NoisefilteronSDA/SCLinputs
Noglitchonpower-up
Supportshotinsertion
Lowstandbycurrent
Operatingpowersupplyvoltage(VDD)rangeof2.3Vto5.5V
5.5Vtolerantinputsonnon-LEDpins
40℃to+85℃operation
ESDprotectionexceeds2000VHBMperJESD22-A114,200VMMperJESD22-A115and1000VCDMperJESD22-C101
Latch-uptestingisdonetoJEDECStandardJESD78whichexceeds100mA
Packagesoffered:LQFP48,HVQFN48
图1.PCA9626方框图
图2.PCA9626典型应用
详情请见PDF文档
来源：NXP
，DPO/MSO4000B和DPO/MSO3000系列示波器是不错的选择；而对于工厂和生产过程的设计优化和参数测试应用，将采用紧凑的SO-8和eDIP?-12封装形式。有关产品数据手册、参考设计及介绍视频，对于全彩LED灯而言，比较信号反馈到运算放大器，Linear公司的LT3798是绝缘无光耦带PFC的反激控制器,功率因素大于0.97,不需要光耦合器,谐波低,恒流和恒压调整,精度在±5%,无负载的功耗小于0.5W,和能源之星标准兼容,主要用在离线5W-100W电源,高DCVIN绝缘应用和离线总线转换器(12V,24V或48V输出).本文介绍了LT3798主要特性,框图以及通用输入24W和48WPFC电源电路图.IsolatedNoOpto-CouplerFlybackControllerwithActivePFC
TheLT®3798isaconstantvoltage/constantcurrentisolatedflybackcontrollerthatcombinesactivepowerfactorcorrection(PFC)withnoopto-couplerrequiredforoutputvoltagefeedbackintoasingle-stageconverter.ALT3798baseddesigncanachieveapowerfactorofgreaterthan0.97byactivELymodulatingtheinputcurrent,allowingcompliancewithmostHarmonicCurrentEmissionrequirements.
TheLT3798iswellsuitedforawidevarietyofoff-lineapplications.TheinputrangecanbescaLEDupordown,dependingmainlyonthechoiceofexternalcomponents.
Efficiencieshigherthan86%canbeachievedwithoutputpowerlevelsupto100watts.Inaddition,theLT3798caneasilybedesignedintohighDCinputapplications.
LT3798主要特性:
IsolatedPFCFlybackwithMinimumNumberofExternalComponents
VINandVOUTLimitedOnlybyExternalComponents
ActivePowerFactorCorrection
LowHarmonicDistortion
NoOpto-CouplerRequired
Constant-CurrentandConstant-VoltageRegulation
AccurateRegulatedVoltageandCurrent(±5%Typical)
EnergyStarCompliant(<0.5WNoLoadOperation)
ThermallyEnhanced16-leadMSOPPackage
LT3798应用:
Offline5Wto100W+Applications
HighDCVINIsolatedApplications
OfflineBusConverter(12V,24Vor48VOutputs)
图1.LT3798方框图
图2.LT3798通用输入24WPFC总线电源电路图
图3.LT3798通用输入48WPFC电源电路图
，。