大功率LED恒流驱动设计及应用

本科毕业论文（设计）题目大功率LED恒流驱动设计及应用学生指导教师年级2011级专业电子信息工程二级学院信息工程学院信息工程学院2015年5月II郑重声明本人的毕业论文（设计）是在指导教师的指导下独立撰写完成的。如有剽窃、抄袭、造假等违反学术道德、学术规范和侵权的行为，本人愿意承担由此产生的各种后果，直至法律责任并愿意通过网络接受公众的监督。特此郑重声明。毕业论文（设计）作者（签名）：年月日III大功率LED恒流驱动设计及应用摘要近年来，大功率LED因其高效、节能、环保、寿命长、高可靠性等优点逐渐在照明领域获得广泛应用，成为21世纪的新一代照明光源。大功率LED产业的蓬勃发展有力地推动了LED驱动集成电路产业的前进，孕育着巨大的商机。该设计主要针对LED在点亮时随着时间增长电阻温度升高最终会影响LED寿命的现状，详细分析了大功率LED恒流驱动、恒压驱动的不同，具体研究了各种恒流驱动方式的特点，设计了一种基于C8051f310的由PWM控制的恒流驱动电路。该驱动电路采用Allegro公司新推出的一种线性电流传感器ACS712芯片作为驱动实现该功能。此芯片内置有精确的低偏置新型霍尔传感器电路，能够输出与检测交流直流电路，方便直观的采集瞬时电流显示在LCD液晶显示屏上。此外该电路满足12V或24V自动输入方式，输出电流以100mA为基准，最大为6A且误差小于2%并能够显示在液晶显示屏上的所有要求，结合实际的应用案例能够达到用户的技术参数要求。关键词：大功率LED恒流驱动C8051f310PWMACS712IVHigh-powerLEDconstantcurrentdriveapplicationandresearchWangYueDirectedbyprofessorWangZhianABSTRACTInrecentyears,highpowerLEDforitshighefficiency,energysaving,environmentalprotection,theadvantagesoflongservicelife,highreliabilitygraduallywinningiswidelyusedinlightingfield,hasbegantoreplaceincandescentlamp,fluorescentlampetctraditionallightingsource,be21centuryofanewgenerationoflightingsource.ThevigorousdevelopmentofhighpowerwhiteLEDindustryvigorouslypromotedtheLEDdriverICindustryforward,pregnantwithenormousbusinessopportunities.Paperthebriefintroductionofthehigh-powerLEDlight-emittingcharacteristics,thevoltamperecharacteristicsanddrivesolutions,onthebasisofdetailedanalyzingthestructureofsingle-chipmicrocomputercontrol,PWMmodulationtypeswitchingpowersupplyandtheadvantagesanddisadvantagesofthecurrentcontrolmodeandthevoltagecontrolmode,thispaperproposesatypeBuckmodeswitchingpowersupplybasedonPWMmodulationconstantcurrentdrivecircuitprinciple,usingC8051f310drivethedesignofhighpowerLEDcircuitchip.Thedrivercircuithas1000:1highlightthan(PWMdimming),lowcurrentconsumption,highefficiency,under-voltageprotection,shortcircuitprotectionandprotectionfunctions,suchasopencircuitofLEDissuitablefordrivinghighbrightnesshighcurrentLED.KEYWORDS：high-powerLEDSwitchingPowerPWMconstant-currentdrivingC8051f310目录前言.................................................................................................................................................11绪论..............................................................................................................................................31.1大功率LED国内外研究现状.........................................................................................31.2设计介绍与研究意义.......................................................................................................41.3大功率LED伏安特性.....................................................................................................41.4驱动方式分析...................................................................................................................51.4.1电阻限流电路........................................................................................................51.4.2电荷泵升压电路....................................................................................................61.4.3开关变换电路........................................................................................................72开关电源控制方式......................................................................................................................72.1电压控制模式...................................................................................................................82.2电流控制模式...................................................................................................................93LED恒流驱动电路设计.............................................................................................................93.151单片机功能综述........................................................................................................113.2C8051f310芯片介绍......................................................................................................123.3Acs712芯片介绍............................................................................................................133.4at24c254芯片介绍.........................................................................................................143.5LM2576芯片介绍..........................................................................................................153.674HC08芯片介绍..........................................................................................................163.7晶振及缓冲电路.............................................................................................................174软件介绍....................................................................................................................................184.1PWM控制程序如下......................................................................................................184.2AD采样程序如下..........................................................................................................194.3数据锁存程序.................................................................................................................194.4数据锁存程序..............................................................................