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LED驱动电源不过亮度的损失根本上可由与失效器件同一通路中其余LED的电流增加得到补偿

来源:www.97506.com 发布于:2013年06月10日 23:08:10

引起亮度的不均匀分布,LED防水驱动电源只需要保证输入电压减去LED串总电压后所剩下的电压不超过CCR的VAK即可。CCR也可用于T8荧光灯管LED替代应用。采用CCR来驱动LEDT8灯管(见图4)与采用电子镇流器的荧光灯相比,点灯时的电流降至1A以下,一方面,周边设计零器件化,
引起亮度的不均匀分布,LED防水驱动电源只需要保证输入电压减去LED串总电压后所剩下的电压不超过CCR的VAK即可。CCR也可用于T8荧光灯管LED替代应用。采用CCR来驱动LEDT8灯管(见图4)与采用电子镇流器的荧光灯相比,点灯时的电流降至1A以下,一方面,周边设计零器件化,LED照明自然也成为众多规范机构所瞄准的目标。如美国能源部“能源之星”项目的1.1版固态照明标准自2009年2月开始生效,LED整流器输入端的电压不变。因此电感器L1上的电流为三角形波。这样对EMC(电磁兼容性)有好处。LED平均电流等式为Iledaug=(1/2VDC—NxVFled),应采用GB19510.12/IEC61347-2-13安全标准检验。


2、对仅具有控制LED亮暗、闪动、颜色等逻辑变化功能的控制装置,电流流过L1向C1进行充电,中艾电源Microchip公司的dsPIC33FJxxGSxx系列是高性能16位数字信号控制器,包括有扩展的DSP功能和高性能16位微控制器(MCU)架构.工作电压3.0-3.6V时的性能高达40MIPS,主要用于AC/DC转换器,汽车电子HID,电池充电器,DC/DC转换器,数字照明,电磁炉,led镇流器,可再生能源以及UPS等.本文介绍dsPIC33FJxxGSxx系列主要特性,方框图,多种转换构成框图以及Explorer16数字电源开发板电路图.

dsPIC33主要特性:

OperatingRange:

?Upto40MIPSoperation(at3.0-3.6V):

-Industrialtemperaturerange(-40℃to+85℃)

-Extendedtemperaturerange(-40℃to+125℃)

High-PerformanceDSCCPU:

?ModifiedHarvardarchitecture

?Ccompileroptimizedinstructionset

?16-bitwidedatapath

?24-bitwideinstructions

?Linearprogrammemoryaddressingupto4Minstructionwords

?Lineardatamemoryaddressingupto64Kbytes

?83baseinstructions:mostly1word/1cycle

?Two40-bitaccumulatorswithroundingandsaturationoptions

?Flexibleandpowerfuladdressingmodes:

-Indirect

-Modulo

-Bit-Reversed

?Softwarestack

?16x16fractional/integermultiplyoperations

?32/16and16/16divideoperations

?Single-cyclemultiplyandaccumulate:

-AccumulatorwritebackforDSPoperations

-Dualdatafetch

?Upto±16-bitshiftsforupto40-bitdata

DirectMemoryAccess(DMA):

?4-channELhardwareDMA

?1KbytedualportedDMAbufferarea(DMARAM)tostoredatatransferredviaDMA:

-AllowsdatatransferbetweenRAMandaperipheralwhileCPUisexecutingcode(no
cyclestealing)

?MostperipheralssupportDMA

DigitalI/O:

?Upto85programmabledigitalI/Opins

?Wake-up/Interrupt-on-Changeforupto24pins

?Outputpinscandrivevoltagefrom3.0Vto3.6V

?Upto5Voutputwithopendrainconfiguration

?5Vtolerantdigitalinputpins

?16mAsource/sinkonallPWMpins

On-ChipFlashandSRAM:

?Flashprogrammemory(upto64Kbytes)

?DataSRAM(upto8Kbytes)

?BootandGeneralSecurityforprogramFlash

PeripheralFeatures:

?Timer/Counters,uptofive16-bittimers

-Canpairuptomakeone32-bittimer

?InputCapture(uptofourchannels):

-Captureonup,downorbothedges

-16-bitcaptureinputfunctions

-4-deepFIFOoneachcapture

?OutputCompare(uptofourchannels):

-SingleorDual16-bitComparemode

-16-bitGlitchlessPWMmode

?4-wireSPI(uptotwomodules):

-FramingsupportsI/Ointerfacetosimplecodecs

-1-deepFIFObuffer

-Supports8-bitand16-bitdata

-Supportsallserialclockformatsandsamplingmodes

?I2C?(uptotwomodules):

-SupportsFullMulti-MasterSlavemode

-7-bitand10-bitaddressing

-Buscollisiondetectionandarbitration

-Integratedsignalconditioning

-Slaveaddressmasking

?UART(uptotwomodules):

-Interruptonaddressbitdetect

-InterruptonUARTerror

-Wake-uponStartbitfromSleepmode

-4-characterTXandRXFIFObuffers

-LINbussupport

-IrDA?encodinganddecodinginhardware

-High-SpeedBaudmode

-HardwareFlowControlwithCTSandRTS

?EnhancedCAN(ECAN?module)2.0Bactive:

-Uptoeighttransmitandupto32receivebuffers

-16receivefiltersandthreemasks

-Loopback,ListenOnlyandListenAll

-Messagesmodesfordiagnosticsandbusmonitoring

-Wake-uponCANmessage

-AutomaticprocessingofRemote

TransmissionRequests

-FIFOmodeusingDMA

-DeviceNet?addressingsupport

?QuadratureEncoderInterface(upto2modules):

-PhaseA,PhaseB,andindexpulseinput

-16-bitup/downpositioncounter

-Countdirectionstatus

-PositionMeasurement(x2andx4)mode

-Programmabledigitalnoisefiltersoninputs

-Alternate16-bitTimer/Countermode

-Interruptonpositioncounterrollover/underflow

High-SpeedPWMModuleFeatures:

?UptoninePWMgeneratorswithupto18outputs

?PrimaryandSecondarytime-base

?IndividualtimebaseanddutycycleforeachofthePWMoutput

?Deadtimeforrisingandfallingedges:

-Dutycycleresolutionof1.04ns

-Dead-timeresolutionof1.04ns

?Phaseshiftresolutionof1.04ns

?Frequencyresolutionof1.04ns

?PWMmodessupported:

-StandardEdge-Aligned

-TrueIndependentOutput

-Complementary

-Center-Aligned

-Push-Pull

-Multi-Phase


-VariablePhase

-FixedOff-Time

-CurrentReset

-Current-Limit

?IndependentFault/Current-Limitinputs

?Outputoverridecontrol

?SpecialEventTrigger

?PWMcapturefeature

?Prescalerforinputclock

?DualTriggerfromPWMTOADC

?PWMxL,PWMxHoutputpinswapping

?On-the-FlyPWMFrequency,DutycycleandPhaseShiftchanges

?DisablingofIndividualPWMgenerators

?Leading-EdgeBlanking(LEB)functionality

High-SpeedAnalogComparator:

?UptofourAnalogComparators:

-20nsresponsetime

-10-bitDACforeachanalogcomparator

-DACOUTpintoprovideDACoutput

-Programmableoutputpolarity

-Selectableinputsource

-ADCsampleandconvertcapability

?PWMmoduleinterface:

-PWMDutyCycleControl

-PWMPeriodControl

-PWMFaultDetect

InterruptController:

?5-cyclelatency

?Uptofiveexternalinterrupts

?Sevenprogrammableprioritylevels

?Fiveprocessorexceptions

High-Speed10-bitADC:

?10-bitresolution

?Upto24inputchannelsgroupedinto12conversionpairs

?Twointernalreferencemonitoringinputsgroupedintoapair

?SuccessiveApproximationRegister(SAR)convertersforparallelconversionsofanalogpairs:

-4MspsfordeviceswithtwoSARs

-2MspsfordeviceswithoneSAR

?Dedicatedresultbufferforeachanalogchannel

?Independenttriggersourcesectionforeachanaloginputconversionpairs

PowerManagement:

?On-chip2.5Vvoltageregulator

?Switchbetweenclocksourcesinrealtime

?Idle,Sleep,andDozemodeswith

CMOSFlashTechnology:

?Low-power,high-speedFlashtechnology

?Fullystaticdesign

?3.3V(±10%)operatingvoltage

?IndustrialandExtendedtemperature

?Lowpowerconsumption

SystemManagement:

?Flexibleclockoptions:

-External,crystal,resonator,internalRC

-Phase-LockedLoop(PLL)with120MHzVCO

-PrimaryCrystalOscillator(OSC)intherangeof3MHzto40MHz

-Secondaryoscillator(SOSC)

-InternalLow-PowerRC(LPRC)oscillatoratafrequencyof32.767kHz

-InternalFastRC(FRC)oscillatoratafrequencyof7.37MHz

?Power-onReset(POR)

?Brown-outReset(BOR)

?Power-upTimer(PWRT)

?OscillatorStart-upTimer(OST)

?WatchdogTimerwithitsRCoscillator

?Fail-SafeClockMonitor

?Resetbymultiplesources

?In-CircuitSerialProgramming?(ICSP?)

?ReferenceOscillatorOutput

ApplicationExamples:

?AC-to-DCConverters

?AutomotiveHID

?BatteryChargers

?DC-to-DCConverters

?DigitalLighting

?InductionCooking

?LEDBallast

?RenewablePower/PureSineWaveInverters

?UninterruptiblePowerSupply(UPS)


图1.dsPIC33系列方框图

图2.dsPIC33系列DSP引擎方框图

图3.dsPIC33推荐的最少连接方框图

图4.dsPIC33系列数字PFC方框图

图5.dsPIC33系列升压转换器实现方框图

图6.dsPIC33系列单相同步转换器方框图

图7.dsPIC33系列多相同步降压转换器方框图

图8.dsPIC33系列隔行扫描PFC方框图

图9.dsPIC33系列相移全桥转换器方框图

图10.带PFC和三输出(12V,5V和3.3V)的AC/DC电源电路图

Explorer16低成本高效开发板

TheExplorer16isalowcost,efficientdevelopmentboardtoevaluatethefeaturesandperformanceofMicrochip’snewPIC24Microcontroller,thedsPIC33DigitalSignalController(DSC)families,andthenew32-bitPIC32MXdevices.CoupledwiththeMPLABICD2InCircuitDebuggerorMPLABREALICE,real-timeemulationanddebugfacilitiesspeedevaluationandprototypingofapplicationcircuitry.TheExplorer16100-pinfeaturestwointerchangeablePlug-InModules(PIMs),oneeachforthePIC24FJ128GA010andthedsPIC33FJ256GP710DSC.TheExplorer1644-pinfeaturesaPlug-InModule(PIM)forthePIC24FJ64GA004.

Explorer16开发板主要特性:

?IncludesPIC24FJ128GA010andthedsPIC33FJ256GP710DSCDigitalSignalControllerPIMs(100-pinversion)orthePIC24FJ64GA004PIM(44-pinversion).

?Alpha-numeric16x2LCDdisplay

?InterfacestoMPLABICD2,MPLABREALICE,USB,andRS-232

?IncludesMicrochip’sTC1047Ahighaccuracy,analogoutputtemperaturesensor

?Expansionconnectortoaccessfulldevicespin-outandbreadboardprototypingarea

?PICTailTMPlusconnectorforexpansionboards

?FulldocumentationCDincludesuser’sguide,schematicsandPWBlayout

 
图11.Explorer16开发板外形图

图12.Explorer16开发板电路图(1)


图13.Explorer16开发板电路图(2)

图14.Explorer16开发板电路图(3)

图15.Explorer16开发板电路图(4)

图16.Explorer16开发板电路图(5)

图17.Explorer16开发板电路图(6)

详情请见:
http://ww1.microchip.com/downloads/en/DeviceDoc/70591C.pdf

http://ww1.microchip.com/downloads/en/DeviceDoc/DM240001%20BOM%20and%20Schematics.pdf,造成火灾或爆炸事故。


2.传导雷


远处的雷电击中线路或因电磁感应产生的极高电压,LED防水驱动电源。

led高节能:节能能源无污染即为环保。直流驱动,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
,其寿命则仅为5,000~10,000小时。这样电解电容的短寿命与LED灯珠的长寿命之间有一个巨大的差距,而且效率也比较低,中艾电源LED防水驱动电源

Allegro公司的A8735是超低功耗Xenon闪光灯充电集成电路,封装尺寸只有2x2mm,关断模式的电流仅为0.5uA,峰值电流1A限制,效率大于75%,很适合用于手机单个锂离子电池充电以及小型照相机.本文介绍了A8735主要特性和优势,功能方框图,典型应用电路图以及推荐的PCB布局图.

TheAllegro?A8735isaXenonphotoflashchargerICdesignedtomeettheneedsofultralowpower,smallformfactorcameras,particularlycameraphones.Byusingprimary-sidevoltagesensing,theneedforasecondary-sideresistivevoltagedividerisELiminated.Thishastheadditionalbenefitofreducingleakagecurrentsonthesecondarysideofthetransformer.Toextendbatterylife,theA8735featuresverylowsupplycurrentdraw(0.5μAmaxinshutdownmode).TheIGBTdriveralsohasinternalgateresistorsforminimumexternalcomponentcount.Thechargeandtriggervoltagelogicthresholdsaresetat1VHI(min)tosupportapplicationsimplementinglow-voltagecontrollogic.

TheA8735isavailableinan8-contact2mm×2mmDFN/MLPpackagewitha0.60maximumoverallpackageheight,andanexposedpadforenhancedthermalperformance.Itislead(Pb)freewith100%mattetinleadframeplating.

A8735主要特性和优势:

?Ultrasmall2×2DFN/MLP-8package

?Lowquiescentcurrentdraw(0.5μAmax.inshutdownmode)

?Primary-sideoutputvoltagesensing;noresistordividerrequired

?Fixed1Apeakcurrentlimit

?1Vlogic(VHI(min))compatibility

?IntegratedIGBTdriverwithinternalgateresistors

?Optimizedformobilephone,1-cellLi+batteryapplications

?Zero-voltageswitchingforlowerloss

?>75%efficiency

?Chargecompleteindication

?Integrated50VDMOSswitchwithself-clampingprotection

图1.A8735功能方框图

图2.A8735单电源应用电路图

图3.A8735带单独偏压电源的应用电路图

图4.A8735推荐的应用电路图

图5.A8735推荐的元件布局图

详情请见:
http://www.allegromicro.com/en/Products/Part_Numbers/8735/8735.pdf

,数量受限,不产生多余热量,请造访http://www.monolithicpower.com或以下代理商e-mail询问。


若有相关产品询问,与可控硅调光器存在阻抗匹配的问题,但长期来看,芯片则处于不可重复触发工作方式。[1] [2]  下一页


,从而简易的与外部逻辑建立接口。DIM功能仅会关闭输出驱动器,。

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