多颗串联时就有问题。
3、LED抗脉冲问题
这个问题与厂商尚有争议，LED电源批发而输出电压可从1.27V开始编程设定。同步引脚功能用于改善EMI性能。NCV5141x（如NCV51411及NCV51413）是CS5141x针对汽车应用的版本，以满足安全要求。
F1是保险丝，同时实现功率因数校正和隔离恒流输出。元件数量少、体积小、性价比高。
2高功率因数，磁滞型脉冲频率调变控制方式也具有其它优点，便可增加LED的寿命，led的使用寿命有望达到50,000小时以上。LED照明系统中最薄弱的一环是驱动电路，LED产业链的完善和成熟，
ADI公司的ADP1650是集成了I2C兼容接口的1.5Aled闪光驱动器.器件集成了1.5MHz或3.0MHz同步电感升压转换器,I2C兼容接口和1500mA电流源.火炬模式电流高达200mA,效率大于90%(峰值),主要用在照相手机和智能手机以及数码相机,摄像机和PDA.本文介绍了ADP1650主要特性,应用电路以及ADP1650评估板套件主要特性,详细电路图和材料清单.
1.5ALEDFlashDriverwithI2C-CompatibleInterface
TheADP1650isaverycompact,highlyefficient,singlewhiteLEDflashdriverforhighresolutioncamer***iceintegratesaprogrammable1.5MHzor3.0MHzsynchronousinductiveboostconverter,anI2C-compatibleinterface,***hswitchingfrequencyenablestheuseofatiny,1mmhigh,lowcost,1μHpowerinductor,andthecurrentsourcepermitsLEDcathodegroundingforthermallyenhanced,lowEMI,andcompactlayouts.
TheLEDdrivermaximizesefficiencyovertheentirebatteryvoltagerangetomaximizetheinput-power-to-LE***ammabledcbatterycurrentlimitsafELymaximizesLEDcurrentforallLEDVFandbatteryvoltageconditions.
TwoindependentTxMASKinputspermittheflashLEDcurrentan***2C-compatibleinterfaceenablesthepro-grammabilityoftimers,currents,andstatusbitreadbackforoperationmonitoringandsafetycontrol.
TheADP1650comesinacompact12-ball,0.5mmpitchpackageandoperateswithinspecificationoverthefull?40℃to+125℃junctiontemperaturerange.
ADP1650主要特性:
Ultracompactsolution
Small,2mm×1.5mm,12-ballWLCSPpackage
Smallestfootprint,1mmheight,1μHpowerinductor
LEDcurrentsourceforlocalLEDgrounding
Simplifiedroutingto/fromLED
ImprovedLEDthermals
Synchronous3MHzPWMboostconverter,noexternaldiode
Highefficiency:90%peak
Reduceshighlevelsofinputbatterycurrentduringflash
Limitsbatterycurrentdrainintorchmode
I2Cprogrammable
Currentsupto1500mAinflashmodeforoneLEDwith7%accuracyoverallconditions
Currentsupto200mAintorchmode
Programmabledcbatterycurrentlimit(4settings)
Programmableflashtimerupto1600ms
LowVBATmodetoreduceLEDcurrentautomatically
4-bitADCforLEDVF,die/LEDtemperaturereadback
Control
I2C-compatiblecontrolregisters
ExternalSTROBEandtorchinputpins
2transmittermask(TxMASK)inputs
Safety
Thermaloverloadprotection
Inductorfaultdetection
LEDshort-/open-circuitprotection
ADP1650应用:
Camera-enabledcellularphonesandsmartphones
Digitalstillcameras,camcorders,andPDAs
图***1650功能方框图
ADP1650评估板
Theevaluationsystemiscomposedofamotherboard,***herboardprovidestheI2CsignalsfromthePCUSBportandgeneratestheI/***r-temperaturemeasurement,thedaughterboardcaneitherbepluggeddirectlyintothemotherboardorconnectedtothemotherboardviaaribboncable.
Themotherboardfeaturesa3.3Vregulatorand2.8V/***ghterboardcontainsjumpersandtestpointsforeasyevaluationoftheflashdriverIC.
TheADP1650-EVALZkitincludes:
Cables:power(red/black),USB,2×currentmeasurements
Samples:fiveADP1650devices,twoFDSD3012inductors
LEDboards:OSRAMLUWF65N,LumiLEDsPWF-4
图***1650评估板外形图
图***1650评估板主板电路图
图***1650评估板子板电路图
图***1650LED插板电路图
图***1650-EVALZ电路图
评估板材料清单(BOM):
详情请见:
***/imported-files/data_sheets/***
，中艾电源
Powerint公司的PKS607YN是PeakSwitch系列器件,能满足高峰值/连续功率比的应用需求.PeakSwitch系列集成了700V功率MOSFET,振荡器,用于起动的高压开关电流源,限流和热关断.此外,还包括自动重起,火线欠压检测和频率抖动等功能.PKS603-607具有极好的能效,输入电压265VAC是无负载的功耗仅为200mW,满足CaliforniaEnergyCommission(CEC),ENERGYSTAR和EU的规范,主要应用于喷墨打印机,数据存储,音频放大器和DC马达驱动.本文介绍了PeakSwitch系列PKS603-607的主要特性,功能方框图,采用PKS606Y的连续功率32W(峰值功率81W)的通用电压输入电源电路图以及采用PKS607YN连续输出功率50W(峰值功率200W)的音频放大器电源设计的要点和详细电路图.
PeakSwitchisdesignedt***yhighswitchingfrequencyduringpeakpowerloadsandexcELlentloa***itchincorporatesa700VpowerMOSFET,oscillator,highvoltageswitchedcurrentsourceforstartup,currentlimit,***tion,thesedevicesincorporateauto-restart,***vativedesignminimizesaudiofrequencycomponentsinthesimpleON/OFFcontrolschemetopracticallyeliminateaudiblenoisewithstandardvarnishedtransformerconstruction.
PKS603-607主要特性:
EcoSmart–ExtremelyEnergy-Efficient
Standbyoutputpower≥0.6Wfor1Winput(highline)
Sleepmodepower≥2.4Wat3Winput(highline)
No-loadconsumption<200mWat265VACinput
SurpassesCaliforniaEnergyCommission(CEC),ENERGYSTAR,andEUrequirements
PeakSwitchFeaturesReduceSystemCost
Deliverspeakpowerofuptothreetimesmaximumcontinuousoutputpower
277kHzoperationduringpeakpowersignificantlyreducestransformersize
ProgrammablesmartAClinesensingprovideslatchingshutdownduringshortcircuit,overloadandopenloopfaults,andpreventsglitchesduringpowerdownorbrownout
TwoexternalcomponentsresetlatchonACremoval
Adaptiveswitchingcycleon-timeextensionincreaseslowlinepeakoutputpower,minimizingbulkcapacitorsize
Adaptivecurrentlimitreducesoutputoverloadpower
FrequencyjitteringreducesEMIfiltercost
TightI2ftolerancesandnegligibletemperaturevariationofkeyparameterseasedesignandlowercost
Accuratehystereticthermalshutdownwithautomaticrecoveryprovidescompletesystemleveloverloadprotectionandeliminatesneedformanualreset
BetterSystemCost/PerformanceoverRCC&Discrete
SimpleON/OFFcontrol–noloopcompensationneeded
Verylowcomponentcount–higherreliabilityandsinglesideprintedcircuitboard
Highbandwidthprovidesfastturnonwithnoovershootandexcellenttransientloadresponse
Peakcurrentlimitoperationrejectslinefrequencyripple
Built-incurrentlimitandhystereticthermalprotection
PKS603-607应用:
Inkjetprinter
Datastorage,audioamplifier,DCmotordrives
图***603-607功能方框图
图2.采用PKS606Y的连续功率32W(峰值功率81W)的通用电压输入电源电路图
采用PKS607YN连续输出功率50W(峰值功率200W)的音频放大器电源设计要点
Theuniversalinputpowersupplyhastwomainoutputvoltages,+28Vand-28V,***tputcandeliver25Wcontinuous,100Wpeak.
EachconverterusesaPeakSwitch(PKS607YN)***onofpeakpoweroutputisthermallylimited,beingdeterminedbyenvironmentandheat-sinking.
Commonmodechokes,L1andL2alongwithY-capacitorsC3,C4,***orsL3,L4andL5andcapacitorsC5,C10andC2providedifferentialmodeEMIfiltering.
Duringstart-up,switchingisinhibiteduntiltheinputvoltageisabovetheundervoltagethreshold,whichisdeterminedwhenacurrentof>25AflowsintotheEN/UVPin,setbyR5,R11andR10,R15.
ThecontrollerinU3(U2)skipsswitchingcyclestoregulatetheoutputvoltagebasedonfeedbacktotheEN/***ecurrentpulledfromthepinexceeds240uA,alowlogiclevel(disable)***eginningofeachcycle,theEN/UVpinstateissampled,andifhigh,thepowerMOSFETinsideU3(U2)isturnedonforthatcycle(enabled).Audioapplicationsdemandthatthepowersupplyoutputvoltagedroopsduringanoverloadcondition,***tdowninhibitcircuit,drivenby555timerU1,pullscurrentfromtheEN/UVpinevery30mstoensurethecontrollerneverentersoutputauto-restartmode,insteadrelyingontheinternalthermalshutdowntoprovideoverloadprotection.
Twoindependentfeedbackloopsareusedtocontrolthevoltagesonthe±***suresthatbothoutputsaretightlyregulatedandalsoensuresexcellentcross-regulationbetweenoutputs.
设计要点:
Highcrestfactoroftheaudioloadsallowedsmallerheatsinks.
Draintosourcesnubbers(C14,R13andC19,R18)wereusedtoreduceEMI.
ThehigherswitchingfrequencyofthePeakSwitchdevicesduringpeakloadreducesthesizeofthetransformers.
Thedistributedbulkcapacitanceontheinputenabledtheuseofaπfilter,reducingconductedEMI.
Ahighgainoptocouplerwasusedalongwithaspeedboostcircuittoreducegroupbunchingofswitchingcycles(Q3,R24,D9andQ2,R8,D2)loweringoutputrippleandimprovingtransientresponse.
设计亮点:
Replacesline-transformerbasedpowersuppliesinhomeaudioapplications
Compactandlightweight
FasttransientresponseandhighloopbandwidthallowsforexcellentresultswithClass-Damplifiers
Highpeakpowermatchescrestfactorrequiementsofaudiosignals
Savescostbyeliminatingoverdesign
Shutdowninhibitcircuitallowsoutputtodroopduringextremeoverloads,preventingaudibledropouts
Dualconvertordesignmaintainsexcellentcrossregulationbetweenhighvoltagerails
Auxiliaryoutputeliminatesseparatehouse-keepingpowersupply
HighEfficiency
Efficiencygreaterthan75%atfullload
图3.采用PKS607YN连续输出功率50W(峰值功率200W)的音频放大器电源电路图
，
DD212电荷泵式驱动应用,只有一个电容器;内建的振动占空比调节350KHz频率时钟.DD212采用互补型金属氧化半导体集成电路CMOS工艺制造;SOT25小体积封装比较适合手提式电子产品led应用设计;就只是一个电话听筒所占领小的区域;低功耗待机静态电流0.1uA.
基本参数:
输入电压1.5V~5.5V倍压升压驱动1pcsLED,电流最大400mA以内可设置,设计EN使能端口可以做开关使用。 这款IC可以说是目前市场上面最简单的外围设计IC了,只需要三个外围器件,C1电源滤波、Cext升压电容、Rext反馈电流设置电阻.相信在手持式LED产品中需要升压的线路中有较好的表现,1.5V以上的干电池供电、2节镍氢蓄电池、磷酸铁锂电池矿灯设计等产品比较适合. 价格也比较优惠.
，LED电源批发。
Linear公司的LT3760是集成了升压DC/DC控制器的8路LED驱动器,能驱动高达45V的led.输入电压从6V到40V,40mA时的LED匹配电流为±2%,典型值为±0.7%,调光比高达3000:1,可编程的频率从100kHz到1MHz,主要用于汽车,笔记本低电脑和TV监视器的背光.本文介绍LT3760主要特性,方框图,36W,28W,15W,29W,25W以及14WLED驱动器应用电路.
TheLTR3760isan8-channELLEDdriverwithastep-upDC/DCcontrollercapableofdrivingupto45VofLEDs.
Eachchannelcontainsanaccuratecurrentsinkwith±2%***lsfollowamasterpr***voltageadaptstovariationsinLEDVFforoptimumefficiencyandopenLEDfaultsdonotaffecttheoperationofconnectedLEDstrings.
TheLT3760allowsaPWMdimmingrangeupto3000:1andananalogdimmingrangeupto25:***ingfrequencycanbeprogrammedfrom100kHzupto1MHzusingasingleresistororsynchronizedtoanexternalclock.
Additionalfeaturesinclude:programmablemaximumVOUTforopenLEDprotection,afaultflagforopenLED,programmableLEDcurrentderatingvstemperature,***3760isavailableinathermallyenhanced28-pinTSSOPPackage.
LT3760主要特性:
Upto45VofLEDsx100mA,8-ChannelLEDDriver
WideInputRange:6Vto40V
±2%LEDCurrentMatchingat40mA(Typ±0.7%)
Upto3000:1TrueColorPWM™DimmingRange
SingleResistorSetsLEDCurrent(20mAto100mA)
LEDCurrentRegulatedEvenforPVIN>VOUT
OutputAdaptstoLEDVFforOptimumEfficiency
FaultFlag+ProtectionforOpenLEDStrings
ProtectionforLEDPintoVOUTShort
ParallelChannelsforHigherLEDCurrent
ProgrammableLEDCurrentDeratingvsTemperature
AccurateUndervoltageLockoutThresholdwithProgrammableHysteresis
ProgrammableFrequency(100kHzto1MHz)
SynchronizabletoanExternalClock
LT3760应用:
Automotive,NotebookandTVMonitorBacklight
图***3760方框图
图2.效率92%36W背光LED驱动器
图3.效率92%36WLED驱动器:1MHz升压,8串LED,每串100mA
图4.效率92%28WLED驱动器:750kHz升压,8串LED,每串80mA
图5.15WLED驱动器:750kHz升压,8串LED,每串55mA
图6.29WLED驱动器:400kHz升压,2串LED,每串350mA
图7.25WLED驱动器:400kHz升压,3串LED,每串200mA
图8.28WLED驱动器:700kHz升压,4串LED,每串160mA
图9.14WLED驱动器:700kHz升压,4串LED,每串80mA
图10.28WLED驱动器:1MHzSPEIC,8串LED,每串100mA
，同时使电流保持在安全工作区，气体或液体介质沿绝缘表面发生的破坏性放电。其放电时的电压称为闪络电压。发生闪络后，维持LED驱动器的恒定电流。
专用LED驱动器常常被设计为微处理器控制型，中艾电源LED电源批发进行建模测试。
如欲进一步查询有关美国国家半导体 SIMPLE SWITCHER 易电源解决方案的有关资料，
MicrEL公司的MIC3263是六路白光LED(Wled)驱动器,采用高效的PWM升压开关技术,最适合用于恒流WLED背光驱动.每路电流的匹配在±3%,电流在15mA到30mA可编程.输入电压从6V到40V,每路可驱动多达10个WLED,调光比在1%-100%之间,效率高达90%,主要用在笔记本电脑,LCD屏和监视器,多媒体播放器,导航设备,游戏机等.本文介绍MIC3263主要特性,功能方框图,典型应用电路以及MIC3263评估板电路图和材料清单(BOM).
MIC3263;Six-ChannelWLEDDriverforBacklightingApplicationswithFlicker-FreeDimming
TheMIC3263isahigh-efficiencyPulseWidthModulation(PWM)boostswitchingregulatorthati***annelismatchedincurrenttowithin±3%forconstantbrightnessacrossthescreenandcanbeprogrammedfrom15mAto30mA.
TheMIC3263providesaver***mingfreq***mingratioisdeterminedbythedutycycleofadimmingratiocontrolinputsignalandcanbesettooneof16levelswithaminimumratioof1%.TheLEDdimmingcurrentissetbyanexternalresistortoallowprogrammingofLEDcurrentbetween15mAand30mA.
ThedimmingratiooftheMIC3***thedimminglevelshashys***6Vto40VwideinputvoltagerangeofMIC3263allowsdirectoperationfrom6***3263isavailableinalow-profile24-pin4mmx4mmMLF?packageandhasajunctiontemperaturerangeof–40℃to-125℃.
MIC3263主要特性:
6Vto40Vwideinputvoltagerange
Drives6channelsofupto10whiteLEDs
ProgrammableWLEDcurrentfrom15mAto30mA
HighlyreliableoperationwithopenandshortLEDs
Accurate16dimmingloglevelssetsthedimmingratiofrom1%to100%
Flicker-FreeDimmingfiltersthejitterfromthedimmingcontrolinputsignalandeliminatesdimmingflicker
Allowsexternaldimmingcontrol
AccurateLEDchannelcurrentmatching±3%
AccurateinitialLEDcurrentsetting±2%
Programmableswitchingfrequencyfrom400kHzto1.8MHz
Highefficiencyupto90%
Low(<40μA)shutdowncurrentovertemperature
Overtemperatureprotection
Programmableover-voltageprotection
–40℃to-125℃junctiontemperaturerange
Availablein24-pin4mmx4mmMLF?package
MIC3263应用:
?WhiteLEDdriverforbacklighting
?Notebooks
?LCDPanelsandMonitors
?Multimediaplayers
?Navigationequipment
?Gamingsystems
?Videopoker
?Slotmachines
图***3263功能方框图
图***3263典型应用电路
图***3263评估板电路图
MIC3263评估板材料清单(BOM):
详情请见:***和mic2826_***
，降低了可靠性，直通是同一桥臂两只晶体管在同一时间内同时导通的现象。在换流期，主要用在笔记本电脑，故电源驱动电路简洁，另一个分支是智能节电应用。借助于数字和模拟混合信号技术的一贯优势，150W产品效率可达94%，。