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1、FairchildFL7794PWM调光大功率LEDAC直接驱动方案时间：2016-06-0612:52:06 作者：Fairchild 来源：中电网Fairchild公司的FL7794是直接从AC线驱动的LED驱动器,从而最小化外接RC无源元件的数量,输入电压90~305VAC.正常配置下一个电阻可调整LED功率,一个电容提供稳定电压来偏置内部并联稳压器.器件提供模拟/PWM可调光特性,采用高PF和低的THD可获得高效率,主要用于高稳定的大功率LED照明系统.本文介绍了FL77944主要特性,框图,以及12W评估板FEBFL7794
2、4A4测试条件,电路图和材料清单.TheFL77944isadirectAClineLEDdriverwithaminimalnumberofexternalRCpassivecomponents.Innormalconfiguration,oneresistoristoadjustLEDpower,andonecapacitoristoprovideastablevoltagetoaninternalbiasingshuntregulator.TheFL77944providesphase-cutdimmingwithwidedimmingrange,
3、smoothdimmingcontrolandgooddimmercompatibility.ItachieveshighefficiencywithhighPFandlowTHD,whichmakestheFL77944suitableforhigh-efficiencyLEDlightingsystems.TheFL77944hasadedicatedDIMpinwhichcanbeusedwithanalogordigitalPWMdimming.TheFL77944canalsobeusedwitharheostatdimmerswitchwhi
4、chissuitablefordesktoporindoorlamps.OperationofFL77944admitsdrivinghigher-wattagesystems,suchasstreetlightsanddownlights,bysimplyparallelconnectingthedriverICs.FL77944主要特性:ThesimplestDirectACLEDDriverwithOnlyTwoExternalRCPassiveComponentWideACInputRange:90~305VACFourIntegratedHig
5、h-VoltageLEDConstantCurrentSinksofupto150mA(RMS)CapabilityTRIACDimmable(Leading/TrailingEdge)RheostatDimmableAnalog/DigitalPWMDimmingFunctionHighPowerFactor(above0.98innormalconfiguration)AdjustableLEDPowerwithanExternalCurrentSenseResistorLowHarmonicContent(THDunder20%innormalco
6、nfiguration)FlexibleLEDForwardVoltageConfigurationPowerScalabilitywithMultipleDriverICsOver-TemperatureProtection(OTP)SOP16EPPackageFL77944应用:LEDLighting–HighPower-Analog/PWMdimming LEDLighting–LowPower–Analog/PWMdimming LEDLighting–MidPower-Analog/PWMdimming Lighting 图1.FL77944简
7、化框图12W评估板FEBFL77944A4HighLine12WDownLightingReferenceDesignforLEDDirectACDriverwithLowFlickerIndex.ThisdocumentdescribesadirectAClineLEDdriverwithaminimalnumberofexternalcomponents.TheinputvoltagerangeoftheLEDdriverboardisclassedashigh-lineapplicationfor198VAC~242VAC,withasingleD
8、Coutput,constantcurrentdependsontheRcsva
