TOP264-271TOPSwitch-JXFamily
TOPSwitch-JXcosteffectivELyincorporatesa725VpowerMOSFET,highvoltageswitchedcurrentsource,multi-modePWMcontrol,oscillator,thermalshutdowncircuit,faultprotectionandothercontrolcircuitryontoamonolithicdevice.
TOP264-271产品亮点:
EcoSmart®-EnergyEfficient
EnergyefficientoverentireloadrangeNo-loadconsumptionbelow100mWat265VAC
Upto750mWstandbyoutputpowerfor1Winputat230VAC
HighDesignFlexibilityforLowSystemCost
Multi-modePWMcontrolmaximizesefficiencyatallloads
132kHzoperationreducestransformerandpowersupplysize
66kHzoptionforhighestefficiencyrequirements
Accurateprogrammablecurrentlimit
Optimizedlinefeed-forwardforlineripplerejection
FrequencyjitteringreducesEMIfiltercost
Fullyintegratedsoft-startforminimumstartupstress
725VratedMOSFET
Simplifiesmeetingdesignderatingrequirements
ExtensiveProtectionFeatures
Auto-restartlimitspowerdeliveryto<3%duringoverloadfaults
Outputshort-circuitprotection(SCP)
Outputover-currentprotection(OCP)
Outputoverloadprotection(OPP)
Outputovervoltageprotection(OVP)
Userprogrammableforhysteretic/latchingshutdown
SimplefastACreset
Primaryorsecondarysensed
Lineundervoltage(UV)detectionpreventsturn-offglitches
Lineovervoltage(OV)shutdownextendslinesurgewithstand
Accuratethermalshutdownwithlargehysteresis(OTP)
AdvancedPackageOptions
eDIP™-12package:
Lowprofilehorizontalorientationforultra-slimdesigns
HeattransfertobothPCBandheatsink
OptionalexternalheatsinkprovidesthermalimpedanceequivalenttoaTO-220
eSIP®-7Cpackage:
VerticalorientationforminimumPCBfootprint
SimpleheatsinkmountingusingclipprovidesthermalimpedanceequivalenttoaTO-220
ExtendedcreepagetoDRAINpin
HeatsinkisconnectedtoSOURCEforlowEMI
图1.TOP264-271功能方框图(E和V封装).
图2.TOP264-271高效19V65W通用输入反激电路图
图3.TOP264-271高效12V30W通用输入反激电路图
采用TOPSwitchTM-JXTOP267VG的薄型36.3WLCD监视器电源薄型36.3WLCD监视器电源主要特性:
Lowprofile<12mmcomponentheight
Verylowstandbyconsumption
<100mWinputpowerwith6mAloadon5Voutputat230VACinput
<90mWinputpowerwith5mAloadon5Voutputat230VACinput
Verylowno-loadinputpower
No-loadInputpowerof55mWat230VACinput
Highfull-loadefficiency
>82%efficiencyat90VAC/60Hz
LowTOPSwitch-JXdevicetemperature
<92℃at90VAC,60Hz,25℃
<100℃at90VAC,60Hz,40℃
>12dBmarginonconductedEMI
Hystereticoutputovervoltageprotection
Hystereticoutputshort-circuitprotection
Hystereticthermaloverloadprotectionwithlargehysteresispreventsboard
temperatures>100℃
薄型36.3WLCD监视器电源指标:
图4.薄型36.3WLCD监视器电源电路图
图5.薄型36.3WLCD监视器电源PCB布局图
材料清单(BOM):
图6.变压器电特性图
,耗电仅为普通白炽灯的1/10,为工程师带来更高的设计灵活性。
设计工具
全新 SIMPLE SWITCHER 易电源设计工具让国内工程师可以轻松为开关电源解决方案构思一款高效率的系统设计,
Allegro公司的A8735是超低功耗Xenon闪光灯充电集成电路,封装尺寸只有2x2mm,关断模式的电流仅为0.5uA,峰值电流1A限制,效率大于75%,很适合用于手机单个锂离子电池充电以及小型照相机.本文介绍了A8735主要特性和优势,功能方框图,典型应用电路图以及推荐的PCB布局图.
TheAllegro?A8735isaXenonphotoflashchargerICdesignedtomeettheneedsofultralowpower,smallformfactorcameras,particularlycameraphones.Byusingprimary-sidevoltagesensing,theneedforasecondary-sideresistivevoltagedividerisELiminated.Thishastheadditionalbenefitofreducingleakagecurrentsonthesecondarysideofthetransformer.Toextendbatterylife,theA8735featuresverylowsupplycurrentdraw(0.5μAmaxinshutdownmode).TheIGBTdriveralsohasinternalgateresistorsforminimumexternalcomponentcount.Thechargeandtriggervoltagelogicthresholdsaresetat1VHI(min)tosupportapplicationsimplementinglow-voltagecontrollogic.
TheA8735isavailableinan8-contact2mm×2mmDFN/MLPpackagewitha0.60maximumoverallpackageheight,andanexposedpadforenhancedthermalperformance.Itislead(Pb)freewith100%mattetinleadframeplating.
A8735主要特性和优势:
?Ultrasmall2×2DFN/MLP-8package
?Lowquiescentcurrentdraw(0.5μAmax.inshutdownmode)
?Primary-sideoutputvoltagesensing;noresistordividerrequired
?Fixed1Apeakcurrentlimit
?1Vlogic(VHI(min))compatibility
?IntegratedIGBTdriverwithinternalgateresistors
?Optimizedformobilephone,1-cellLi+batteryapplications
?Zero-voltageswitchingforlowerloss
?>75%efficiency
?Chargecompleteindication
?Integrated50VDMOSswitchwithself-clampingprotection
图1.A8735功能方框图
图2.A8735单电源应用电路图
图3.A8735带单独偏压电源的应用电路图
图4.A8735推荐的应用电路图
图5.A8735推荐的元件布局图
详情请见:
http://www.allegromicro.com/en/Products/Part_Numbers/8735/8735.pdf
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。
①分路保护
一般LED灯是分成很多串接支路。我们可以在每个支路的前面加一支PTC组件分别进行保护。这种方式的好处是精确性高,不会滋生尺寸方面的不利影响。实际上,。