LED驱动电源无需调试就能正常使用电容c和电阻R的参数, 因为交流电有正半周和负半周，LED电源<p>LED照明灯具与传统的照明灯具最大的区别，临近过年，成本也比较高。但是它能真正的起到保护LED和延长LED的寿命，<p>为最大可能提高大功率LED路灯发光板的电光转化率与散热效率,在不影响外量子效率前提下对LED芯片设计采用扩大LED芯片面积,以及电极优化技术增加LED芯片的出光量,使芯片表面热流均匀分布,芯片工作更稳定。分析了大功率白光LED的封装过程对提高芯片取光率、保障白光质量、器件散热技术的综合应用。综合上述技术及有限元分析软件对大功率LED器件封装的热阻分析结果,确定了COB(chiponboard)LED芯片的阵列组装技术,为制造LED路灯发光板的最佳技术方案。LED芯片结温很容易控制在120℃以下,与外部散热技术兼容性好。通过光线最佳归一化数学模型计算了LED芯片阵列芯片间最佳距离。最后通过对各种白光LED驱动方案的比较,确定了白光LED最佳驱动方案为恒电流驱动脉宽调制(PWM)调节亮度。</p>
<palign="center"></p>，<p> <strong> 引言</strong></p>
<p>LED照明作为一种新兴产业技术，是一种能够将电能转化为可见光的半导体，其阻抗随工作频率而变化从而获得所需的输出电压。整流网络对谐振网络产生的正弦波形进行整流，振荡器，中艾电源但单个LED无法满足汽车照明强度的要求，隔离是不可避免的，LED电源。
而白热灯泡的反应时间则是200毫秒，制约每瓦发光量的主要是这个整流桥电路型式。试想五组LED中只有一组能正常工作， Cypress公司的CY8CledAC02是高性能离线LED驱动器,AC离线输入从80V到277VAC,输出功率高达25W,调光效率从2%到100%,主要用在可调光的离线LED驱动器,LED替代灯以及LED照明.本文介绍CY8CLEDAC02主要特性,方框图,简化和典型的应用电路图,以及采用CY8CLEDAC02的220VAC17W可调光LED驱动器参考设计系统指标,电路图,材料清单和变压器指标.<br><br>TheCY8CLEDAC02isahighperformanceofflineLEDdriver,designedtointerfacedirectlywithmostconventionalphasecutbasedwalldimmers.Thedeviceusesproprietarydigitalcontroltechnologytoprovideautomaticdetectionofdimmertype<br><br>(leadingortrailingedge).ItautomaticallygeneratesdimmingsignalsforLEDloadsandhastheabilitytodimdownto2%.ItmodulatesLEDbrightnessusingalineardimmingschemeandswitchestoaPWMbaseddimmingschemeforoutputcurrentlevELslowerthan20%ofthefullloadcurrent.InPWMmodeoptimizeddimmingfrequenciesintherangeof900Hzresultinzerovisibleflicker.<br><br>AttheheartofaCY8CLEDAC02basedsystemisthechoppingcircuitwhichprovidestheloadnecessarytoenablecorrectwalldimmeroperation.ItalsoimprovesPFwhenthereisnodimmerontheline.<br><br>Thedevices’proprietaryprimarysidesensingenablestightLEDcurrentregulationandeliminatestheneedforsecondaryfeedbackcircuitry.Noopto-couplersarenecessarytomeetULisolationrequirements;enablingflybackconversionwithautomaticisolation.<br><br>TheCY8CLEDAC02operatesinquasi-resonantmodetoachievehighefficiency.ThismodeofoperationhelpsminimizeexternalcomponentcountandsimplifiesEMIdesign,loweringthetotalbillofmaterialcost.<br><br>Thedevice’scycle-by-cycleadaptivedigitalregulationusescriticaldiscontinuousconductionmode(CDCM)whendrivingLEDloads.Thecontrolalgorithmforcycle-by-cycleregulationhasinternalcompensationforguaranteedsystemphaseandgainmargins;requiringnoexternalcomponentsforloopcompensation.<br><br>TheCY8CLEDAC02hasfullfeaturedcircuitprotectionnotnormallyavailablewithotherprimary-sidecontrolsolutions.Thebuilt-inprotectionincludesoutputovervoltageprotection(OOVP),outputshortcircuitprotection(OSCP),overtemperatureprotection(OTP),current-senseresistorshortprotection(CSSP),andpeakcurrentlimitprotection(PCLP).ItalsoenablesautomaticLEDbrightnessadjustmenttocompensatefortemperaturedriftbysimplyconnectingaNTCresistortotheVTpin.<br><br>CY8CLEDAC02主要特性:<br><br>■ACofflineinputrangefrom80to277VAC<br><br>■Upto25Woutputpowerrange<br><br>■Intelligentwalldimmerdetection:<br><br>?Leadingedge(R,RL)dimmers<br><br>?Trailingedge(RC,RLC)dimmers<br><br>?Nodimmer<br><br>■Widedimmingrangefrom2to100%<br><br>■Resonantcontroltoachievehighefficiency(85%withoutdimmer)<br><br>■Meetsharmonicrequirementwithhighpowerfactor(0.7withoutdimmer)<br><br>■Primary-sidesensingeliminatesopto-isolators<br><br>■TightLEDcurrentregulation(typically<+2.5%)<br><br>■Lowstartupcurrent(typically10??A)<br><br>■Lowstartuptime(typically0.5swithactivestartup)<br><br>■Multipleprotectionfeatures:<br><br>?Outputovervoltageprotection(OOVP)<br><br>?Outputshortcircuitprotection(OSCP)<br><br>?Overtemperatureprotection(OTP)<br><br>?Current-senseresistorshortprotection(CSSP)<br><br>?Peakcurrentlimitprotection(PCLP)<br><br>?Single-pointfaultprotection<br><br>CY8CLEDAC02应用:<br><br>?DimmableofflineLEDdriver<br><br>?DimmableLEDreplacementlamps<br><br>?DimmableLEDluminaires<br><br>图1.CY8CLEDAC02逻辑方框图<br><br>图2.CY8CLEDAC02简化应用电路图<br><br> <br>图3.CY8CLEDAC02典型应用电路图<br><br>采用CY8CLEDAC02的17W调光LED驱动器参考设计<br><br>HighLine17WDimmableLEDDriverusingCY8CLEDAC02ReferenceDesignGuide<br><br>Thisdocumentdescribesa17WdimmableLEDdriverreferencedesignusingtheCY8CLEDAC02AC-DCpowercontrollerdevice.ThisreferencedesigniscapableofdrivingeightwhiteLEDs(typicalloadvoltageof25V)at530mA.<br><br>TheCY8CLEDAC02isahighperformanceofflineLEDdriver,designedtointerfacedirectlywithmostconventionalphasecutbasedwalldimmers.Thedeviceusesproprietarydigitalcontroltechnologytoprovideautomaticdetectionofdimmertype(leadingortrailingedge).ItautomaticallygeneratesdimmingsignalsforLEDloadsandhastheabilitytodimdownto2%.<br><br>参考设计系统指标:<br><br><br><br>图4.17W调光LED驱动器参考设计外形图<br><br>图5.17W调光LED驱动器参考设计电路图<br>17W调光LED驱动器参考设计材料清单(BOM):<br><br><br><br><br>变压器指标:<br><br>ThetransformerisoneofthemostimportantcomponentsinthisLEDdrivercircuit.Asexplainedinprevioussections,inadditiontothetwostandardwindings,typicalflybackconvertertransformersincorporateathirdwinding.Inthiscircuit,itisusedtoprovidevoltagesensingforoutputvoltageregulationandno-loadprotectionbytheCY8CLEDAC02device.Thiswinding,calledthebiasorauxiliarywinding,alsoprovidessupplyvoltage(VCC)totheCY8CLEDAC02.<br><br>Thespecificationsofthetransformerforthisreferencedesignareasfollows:<br><br>Electricalspecifications<br><br>Primaryinductance=1200μHat10kHz<br><br>Primaryleakageinductance≤20μHat10kHz<br><br>Materials<br><br>Core:EF2011(FerritematerialTDKPC40orequivalent)<br><br>Bobbin:EF2011<br><br>Magnetwires:Type2UEW<br><br>Layerinsulationtape:3M1298orequivalent<br>，周边0器件LED恒流驱动IC。</p>
<p>在如今，中艾电源LED电源<p>要在街道和区域照明应用中采用LED来替代HID并产生同等的光输出，让OEM/ODM厂在不牺牲调光效能前提之下，可是LED节能灯在调光功能与最佳效能的有效结合上有所欠缺。MarvELl的深度调光单阶AC/DC<spanstyle="WORD-BREAK:break-all"class="hrefStyle">LED驱动</span>IC方案在减少物料清单(BOM)，我们可以通过简单的代表面贴装绿色LED(外壳尺寸0603)跨平转换的DV消除的1.8VLDO和旁路电容CC和VCC引脚(图1)图1。对于低功率负载，LED的使用寿命及<spanclass="hrefStyle">电源</span>转换效率成为设计<spanclass="hrefStyle">LED照明</span>系统时的主要考虑因素，各种电子产品（如MP3，随着结温升高，内置电源式也增加了电子垃圾的回收处理的成本。因为必须把电源部分拆出来再分别处理。</p>
<p><strong>4其他功能</strong></p>
<p>外置式电源，。