标签: 大功率led驱动

Thecircuitandfirmwaredescribedinthisapplicationnotedemonstratesaminimalpartscountdriver/control-lerforahigh-power(1Worgreater)LED.Thecircuitisbasedonabucktopologyswitchingpowersupplyusingtheon-chipcomparatorperipheralwithinthePIC12F675PIC®microcontroller.TheswitchingpowersupplydesignensuresefficientpowertransferbetweenthesystembatteryandtheoutputLED.TheFlashPICmicrocontrollerisusedtoimplementintensitycontrol,automatedintensitycompensationforlowbatteryconditions,andtheabilitytoplaybackpre-programmedFlashsequences.TheFlashPICmicro-controlleralsoallowsthecreationofacustomPC-basedgraphicaluserinterface,usingthePICkit™1FlashStarterKitforprogrammingthepre-programmedFlashsequences.Thecombinationoftheswitchingpowersupplydesignandthemicrocontrollerresultsinanefficientcircuitwithadvancedautomatedfeatureswhilekeepingthecircuitsimpleandinexpensive.AN874BuckConfigurationHigh-PowerLEDDriverVoltageandCurrentAuthor:KeithCurtisMicrochipTechnologyInc.The1wattchosenmodulerequiresatypicaldriveof3.4Vat350mAtoproduceitsfulloutputbrightness.Themaximumcurrentdrivefortheunitis500mA.INTRODUCTIONExceedingthemaximumcurrentspecificationforthemodule,evenbyshortdurati……