iW3620是高性能AC/DC離線LED驅動器，器件在高負載條件下工作在準諧振模式，以得到高的效率和各種內置的保護特性，降低EMI，工作頻率高達130kHz，通用輸入電壓85Vac到264Vac，可驅動40W的LED照明。本文介紹了iW3620主要特性以及典型應用電路。 iW3620：DigitalPWMConstantCurrentControllerforAC/DCLEDDriverTheiW3620isahighperformanceAC/DCofflineLEDdriverwhichusesdigitalcontroltechnologytobuildpeakcurrentmodePWMflybackpowersupplies.Thedeviceoperatesinquasi-resonantmodeatheavyloadtoprovidehighefficiencyalongwithanumberofkeybuilt-inprotectionfeatureswhileminimizingtheexternalcomponentcount,simplifyingEMIdesignandloweringthetotalbillofmaterialcost.TheiW3620removestheneedforsecondaryfeedbackcircuitrywhileachievingexcellentlineandloadregulation.Italsoeliminatestheneedforloopcompensationcomponentswhilemaintainingstabilityoveralloperatingconditions.Pulse-by-pulsewaveformanalysisallowsforaloopresponsethatismuchfasterthantraditionalsolutions,resultinginimproveddynamicloadresponse.Thebuilt-incurrentlimitfunctionenablesoptimizedtransformerdesigninuniversaloff-lineapplicationsoverawideinputvoltagerange. iW3620主要特性：Primary-sidefeedbackeliminatesopto-isolatorsandsimplifiesdesignQuasi-resonantoperationforhighestoverallefficiencyandlowEMIUpto130kHzswitchingfrequencyenablessmallsizeVerytightLEDconstantcurrentregulationBuilt-inoutputconstant-currentcontrolwithprimary-sidefeedbackforLEDdriver.Lowstart-upcurrent(10 Atypical)Built-insoftstartBuilt-inshortcircuitprotectionandoutputovervoltageprotectionCurrentsenseresistorshortprotectionOver-temperatureProtectionOpencircuitprotectionUniversalinputrangefrom85Vacto264VacSingle-faultprotectionSmallinputbulkcapacitorLongMTBFHighefficiency iW3620應用：SolidStateLEDlightingforincandescent,halogen,andfluorescenttubereplacement圖1iW3620典型應用電路