ST L6727单相PWM控制器应用方案-技术方案

精品文档-下载后可编辑STL6727单相PWM控制器应用方案-技术方案ST公司的L6726A单相PWM控制器嵌入了大电流驱动器,很容易就能建立起通用的有极好性能的DC/DC降压转换器,成本低.输入电压从5V到12V,输出电压可低至1.5V,可广泛应用于各种子系统的电源如MCH,IOCH和PCI等,存储器和端口电源,CPU和DSP电源以及分布式电源等.本文介绍了L6727和L6726A的主要性能,方框图以及应用电路图.L6726ASinglephasePWMcontrollerTheL6726AandL6727arelow-costsingle-phasePWMcontrollers,withembeddedhigh-currentdrivers,enablingtheeasycreationofgeneralpurposeDC-DCstep-downconverterswithexcellentperformanceforabroadrangeofapplications–fromdesktopPCsub-systems,suchasmemoriesandchipsets,togeneral-purposepowersupplies.Withtheirhighlevelofintegration,thesecompactSO-8devicesallowasignificantreductioninthecostandsizeofthepowersupply.L6726Aisasingle-phasestep-downcontrollerwithintegratedhigh-currentdriversthatprovidescompletecontrollogic,protectionsandreferencevoltagetorealizeinaneasyandsimplewaygeneralDC-DCconvertersbyusingacompactSO-8package.DeviceflexibilityallowsmanagingconversionswithpowerinputVINaslowas1.5Vanddevicesupplyvoltagerangingfrom5Vto12V.L6726Aprovidessimplecontrolloopwithtransconductanceerroramplifier.Theintegrated0.8Vreferenceallowsregulatingoutputvoltagewith±1%accuracyoverlineandtemperaturevariations.Oscillatorisinternallyfixedto270kHz.L6726Aprovidesprogrammableovercurrentprotection.CurrentinformationismonitoredacrosstheLow-SidemosfetRdsONsavingtheuseofexpensiveandspace-consumingsenseresistors.FBdisconnectionprotectionpreventsexcessiveanddangerousoutputvoltagesincaseoffloatingFBpin.主要特性:■Flexiblepowersupplyfrom5Vto12V■Powerconversioninputaslowas1.5V■1%outputvoltageaccuracy■High-currentintegrateddrivers■Adjustableoutputvoltage■0.8Vinternalreference■SensorlessandprogrammableOCPacrossLow-sideRdsON■Oscillatorinternallyfixedat270kHz■Programmablesoft-start■LS-LESSstartup■Disablefunction■FBdisconnectionprotection■SO-8package应用范围:■Subsystempowersupply(MCH,IOCH,PCI...)■MemoryandterminationSuppl