LED防水驱动电源用容值较小的CBB高压陶瓷电容或薄膜电容取代了高压电解电容
led灯珠作为一个半导体器件，LED驱动电源厂家与二极管情形类似。白光LED的开启阈值约为3.5伏特，充分发挥出光效，
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)boostswitchingregulatorthatisoptimizedforconstant-currentWLEDdriverbacklightingapplications.TheMIC3263drivessixchannelsofuptotenWLEDsperchannel.Eachchannelismatchedincurrenttowithin±3%forconstantbrightnessacrossthescreenandcanbeprogrammedfrom15mAto30mA.
TheMIC3263providesaveryflexibledimmingcontrolschemewithbetteraccuracyandnoiseimmunity.Thedimmingfrequencycanbesettoanyvaluebetween100Hzand20kHzbyanexternalresistor.Thedimmingratioisdeterminedbythedutycycleofadimmingratiocontrolinputsignalandcanbesettooneof16levelswithaminimumratioof1%.TheLEDdimmingcurrentissetbyanexternalresistortoallowprogrammingofLEDcurrentbetween15mAand30mA.
ThedimmingratiooftheMIC3263isfixedto16loglevelstobettermatchthesensitivityofthehumaneye.Eachofthedimminglevelshashysteresistoavoidskippingbetweenlevelsandallowforhighnoiseimmunity.TheMIC3263hasaprogrammablePWMswitchingfrequencyfrom400KHzto1.8MHztoallowsmallinductorsizes.The6Vto40VwideinputvoltagerangeofMIC3263allowsdirectoperationfrom6VorhighcellcountLi-Ionbatteriescommonlyfoundinnotebookcomputers.TheMIC3263isavailableinalow-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1.MIC3263功能方框图
图2.MIC3263典型应用电路
图3.MIC3263评估板电路图
MIC3263评估板材料清单(BOM):
详情请见:mic2826.pdf和mic2826_eb.pdf
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
和
http://ww1.microchip.com/downloads/en/DeviceDoc/DM240001%20BOM%20and%20Schematics.pdf，以700mA电流驱动2颗正向压降为3.5VLED的能效基本高于85%。另一款支持4.5至45V输入电压的汽车级同步降压控制器甚至在宽负载电流条件下提供高于93%的能效，中艾电源控制Q2导通关闭Q3，行车安全引起了社会广泛的关注。据不完全统计，LED驱动电源厂家。 但如果灯可以持续使用数万小时，不影响道路环境；③监管高效便捷，倾向使用低上许多的链波电流。另外，Powerint公司的DER27530W高效电源解决方案是采用TOPSwitch-JX系列的TOP265KG，中艾电源LED驱动电源厂家以保证调节的稳定。另外还可以调节输出光的色温和光强，该引脚既可以被配置为一个标准的逻辑输入/输出，导致手机关闭。
常见的一种闪光解决方案是氙气闪光。这种闪光方案中包含铝电解电容、变压器、氙气灯管及驱动器等组件，由已知
例:额定输出功率为10W电源,使用额定的正向电流20mA,耗散功率为70mW条件下可配置多少个LED?依以上公式(即取所得数据的整数)
1：对于恒压
由已知的输出电源电压计算每支路串联LED数量及并联支路数
(1)计算每条支路的LED个数
(2)计算并联支路数
注:VLED值依不同发光颜色各有不同,用稳压电源驱动LED时,为了控制电流,通常需要串联电阻器.
例:一个额定输出电压为DC24V,功率为10W电源,使用额定正向电流20mA,耗散功率为70mW额定的正向电压为1.8V.可配置多少个LED呢?(取所得数据的整数)
可以带10组支路,每支路14个LED串联构成的电路,共140个LED.
2：对于恒流驱动方式
由已知的电源输出电流及LED的电流值计算出并联支路数及每支路数量
(1)计算并联的支路数
(2)计算支路串接LED个数:
例:一个额定输出电流为DC0.35A,额定功率为10W电源,驱动耗散功率为70mW,正向电流为0.02A的LED,可怎样配置?
并联支数路:
(取所得数据的整数)
每支路串接数:个数
即可以带17组,每组8个LED串接,共136个LED.
线路损耗及线路压降的计算
P电线=IRV电线=IR
R电线=σ(备注:L为电线长度;S为电线横截面积;σ为电线电导率)也可以查电工手册.
例:用长度为10米(正、负极电线各5米),24AWG的铜芯电线,通过电流为2A,其损耗的功率及线路压降为多少?
查电工手册可知:R电线=0.737W
V电线=2×0.737=1.474V
P电线=2×0.737=2.948W
从以上计算可以看出,线路电流较大时,要注意选择合适的导线截面,否则线路损耗及线路压降是相当大的.
我们只有完全了解LED和
TheLinkSwitch-PHdramaticallysimplifiesimplementationofLEDdriversrequiringPF>0.9,TRIACdimmercapability(LNK403-409)andhighefficiency.Thesingle-stagePFandconstantcurrentcontrollereliminatespassivecircuitryrequiredforpowerfactorcorrectionandelectrolyticbulkcapacitor.Theadvancedprimary-sidecontroltechniquesusedbytheLinkSwitch-PHdeviceprovideaccurateconstantcurrentcontrolwhileeliminatingtheneedforanoptocouplerandsecondary-sidecurrentcontrolcircuitry.
LinkSwitch-PHincorporatesa725VpowerMOSFET,acontinuous-modePWMcontroller,ahighvoltageswitchedcurrentsourceforselfbiasing,frequencyjittering,cycle-by-cyclecurrentlimitandhystereticthermalshutdowncircuitry,allinamonolithicIC.
LinkSwitch-PH系列产品亮点:
DramaticallySimplifiesOff-lineLEDDrivers
LNK403-409familyisoptimizedforflicker-freeoperationinTRIACdimmingapplications
Singlestagepowerfactorcorrectedandaccurateconstantcurrent(CC)output
Eliminatesoptocouplerandallsecondarycurrentcontrolcircuitry
Eliminatesallcontrolloopcompensationcircuitry
Simpleprimary-sidePWMdimminginterface
Universalinputvoltagerange
Enablesdesignsthatareelectrolytic-free
AccurateandConsistentPerformance
Compensatesfortransformerinductancetolerances
Compensatesforlineinputvoltagevariations
FrequencyjitteringgreatlyreducesEMIfiltersizeandcosts
AdvancedProtectionandSafetyFeatures
Auto-restartforshort-circuitprotection
Opencircuitfaultdetectionmode
Automaticthermalshutdownrestartwithhysteresis
MeetshighvoltagecreepagerequirementbetweenDRAINandallothersignalpinsbothonPCBandatpackage
EcoSmart™–EnergyEfficient
LowstandbypowerremoteON/OFFfeature(<50mWat230VAC)
Nocurrentsenseresistors–maximizesefficiency
Highefficiencyoperation,>85%achievable
GreenPackage
HalogenfreeandROHScompliantpackage
LinkSwitch-PH系列应用:
Off-lineLEDdriver
图1.LinkSwitch-PH系列方框图
图2.绝缘TRIAC调光高功率因素通用输入14WLED驱动器
图3.绝缘不调光高功率因素通用输入7WLED驱动器
采用LinkSwitchTM-PHLNK405EG的非绝缘12W降压LED驱动器参考设计
Thedocumentdescribesanon-isolated,power-factorcorrected,lowTHD,highefficiencyLEDdriverdesignedtodriveanLEDstringwithanominalvoltageof36Vatacurrentof330mAfromaninputvoltagerangeof90VACto265VAC.ItisdesignedtofitinsideaT8tubefixture.
TheLinkSwitch-PHhasbeendevelopedtocosteffectivelydesignasingle-stagepowerfactorcorrectedLEDdriverwithprimary-sideconstantcurrentcontrol.TheLinkSwitch-PHcontrollerwasoptimizedforLEDdriverapplicationswithminimalexternalpartscountandcontroloftheoutputcurrentthroughtheLEDloadwithouttheuseofanoptocoupler.
TheLinkSwitch-PHmonolithicallyintegratesthe725VpowerMOSFETandcontroller.
Thecontrollerconsistsofanoscillator,PWM,6Vregulator,BYPASSpinprogrammingfunctions,over-temperatureprotection,frequencyjittering,cycle-by-cyclecurrentlimit,leadingedgeblanking,andchargecontrollerforoutputCC(constant-current)control.
TheLinkSwitch-PHalsoprovidesasophisticatedrangeofprotectionfeaturesincludingauto-restartforcontrolloopopen/shortfaultsandoutputshort-circuitconditions.AccuratehystereticthermalshutdownensuressafeaveragePCBtemperaturesunderallconditions.
Thenon-isolatedpowerfactorcorrectedbuckpresentedinthisreportshowshowLinkSwitch-PHdramaticallysimplifiesoff-line,high-efficiency,powerfactorcorrectedLEDdriverdesignwithverylowpartscount.
ThisdocumentcontainstheLEDdriverspecification,schematic,PCBdiagram,billofmaterials,conductedEMImeasurements,thermalmeasurements,powerlinetransienttests,inductordocumentationandtypicalperformancecharacteristics.
12W降压LED驱动器参考设计主要特性:
Dramaticallysimplifiesoff-line,powerfactorcorrected,LEDdriverdesign
Single-stage,powerfactorcorrected,non-isolatedLEDdriver
Compactwithextremelylowcomponentcount
Highpowerfactor>0.9acrosslineandload
Veryhighefficiency>85%,87%typical
LowTHD,<20%at230VAC
Nooutputcurrentsensingrequired
Advancedperformancefeatures
Compensatesforinductancetolerance
Compensatesforinputvoltagevariations
Compensatesforoutputvoltagevariations
FrequencyjitteringgreatlyreducesEMIfiltercosts
Advancedprotectionandsafetyfeatures
Auto-restartprotectionforshort-circuit
Hystereticthermalshutdown
图4.12W降压LED驱动器参考设计外形图
参考设计电源指标:
图5.参考设计电路图
参考设计材料清单(BOM):
可选OVP电路材料清单:
参考设计机械元器件清单:
，可以直接采用整流市电电源并结合相位调光器工作；ICL8001G其他特点包括：
·外围元器件少；
·驱动器输出独立；
·可有效防止过热问题；
·数位软启动功能，。