Linear LT3518 LED驱动器解决方案

LinearLT3518LED驱动器解决方案关键词：LT3518LED,DC/DC转换器Linear公司的LT3518LED是电流模式DC/DC转换器，内置了用来驱动LED的2.3A,45V开关。LT3518具有3000:1真色彩PWM调光比，从250kHz到2.5MHz的可调工作频率，主要应用在显示器背景光，汽车电子，照明以及扫描仪。本文介绍LT3518的主要性能，方框图以及多种典型的应用电路图。LT3518-Full-FeaturedLEDDriverwith2.3ASwitchCurrentTheLT®3518isacurrentmodeDC/DCconverterwithaninternal2.3A,45VswitchspecificallydesignedtodriveLEDs.TheLT3518operatesasaLEDdriverinboost,buckandbuck-boostmodes.Itcombinesatraditionalvoltageloopandauniquecurrentlooptooperateasaconstant-currentsourceorconstant-voltagesource.Programmableswitchingfrequencyallowsoptimizationoftheexternalcomponentsforefficiencyorcomponentsize.TheswitchingfrequencyoftheLT3518canbesynchronizedtoanexternalclocksignal.TheLEDcurrentisexternallyprogrammablewitha100mVsenseresistor.TheexternalPWMinputprovides3000:1LEDdimming.TheCTRLpinprovidesfurther10:1dimmingratio.4mm)package.TheLT3518providesacompletesolutionforbothconstant-voltageandconstant-currentapplications.TheLT3518isavailableinthetinyfootprintQFNUF16(4mm主要特性：■3000:1TrueColorPWMTMDimmingRatio■2.3A,45VInternalSwitch■100mVHighSideCurrentSense■OpenLEDProtection■AdjustableFrequency:250kHzto2.5MHz■WideInputVoltageRange:Operationfrom3Vto30VTransientProtectionto40V■OperatesinBoost,BuckModeandBuck-BoostMode■GateDriverforPMOSLEDDisconnect*■Constant-CurrentandConstant-VoltageRegulation■CTRLPinProvides10:1AnalogDimming■LowShutdownCurrent:1μA4mm)16-PinQFNPackage■Tiny(4mm应用：■DisplayBacklighting■AutomotiveandAvionicLighting■Illumination■Scanners图1。LT3518方框图图2。典型应用图3。降压模式1.5ALED驱动器电路图4。500mA5V-12V升压转换器图5。降压/升压模式LED驱动器电路AO-Electronics傲壹电子官网：中文网：。带LED开路保护的降压模式1.0ALED驱动器电路图7。带LED开路保护的升压模式300mALED驱动器电路