资源描述：
《fairchild fl7794 pwm调光大功率led ac直接驱动方案》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
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
2、板FEBFL77944A4测试条件,电路图和材料清单.TheFL77944isadirectAClineLEDdriverwithaminimalnumberofexternalRCpassivecomponents.Innormalconfiguration,oneresistoristoadjustLEDpower,andonecapacitoristoprovideastablevoltagetoaninternalbiasingshuntregulator.TheFL77944providesphase-cutdimmingw
3、ithwidedimmingrange,smoothdimmingcontrolandgooddimmercompatibility.ItachieveshighefficiencywithhighPFandlowTHD,whichmakestheFL77944suitableforhigh-efficiencyLEDlightingsystems.TheFL77944hasadedicatedDIMpinwhichcanbeusedwithanalogordigitalPWMdimming.TheFL77944canalsobeus
4、edwitharheostatdimmerswitchwhichissuitablefordesktoporindoorlamps.OperationofFL77944admitsdrivinghigher-wattagesystems,suchasstreetlightsanddownlights,bysimplyparallelconnectingthedriverICs.FL77944主要特性:ThesimplestDirectACLEDDriverwithOnlyTwoExternalRCPassiveComponentWid
5、eACInputRange:90~305VACFourIntegratedHigh-VoltageLEDConstantCurrentSinksofupto150mA(RMS)CapabilityTRIACDimmable(Leading/TrailingEdge)RheostatDimmableAnalog/DigitalPWMDimmingFunctionHighPowerFactor(above0.98innormalconfiguration)AdjustableLEDPowerwithanExternalCurrentSen
6、seResistorLowHarmonicContent(THDunder20%innormalconfiguration)FlexibleLEDForwardVoltageConfigurationPowerScalabilitywithMultipleDriverICsOver-TemperatureProtection(OTP)SOP16EPPackageFL77944应用:LEDLighting–HighPower-Analog/PWMdimming LEDLighting–LowPower–Analog/PWMdimming
7、 LEDLighting–MidPower-Analog/PWMdimming Lighting 图1.FL77944简化框图12W评估板FEBFL77944A4HighLine12WDownLightingReferenceDesignforLEDDirectACDriverwithLowFlickerIndex.ThisdocumentdescribesadirectAClineLEDdriverwithaminimalnumberofexternalcomponents.TheinputvoltagerangeoftheLEDd
8、riverboardisclassedashigh-lineapplicationfor198VAC~242VAC,withasingleDCoutput,constantcurrentdependsontheRcsva
