标签: lt1508lt1509

离线式电源的增长使功率因数校正(PFC)成为必须的部分，以减少输入电流，满足未来调整的需要。开关电源采用桥式整流器，后接一个大电容，这会产生谐波电流。这些谐波只会增加电源的RMS输入电流，对真正的功率没有任何贡献。LT1508和LT1509通过集成PFC和脉宽调制器(PWM)，可完全满足这一设计需要。advertisementSingleIC,PowerFactorCorrected,Off-LineSupplyDesignNote143KurkMathewsAneverincreasingnumberofoff-linepowersuppliesnowlowerpartcountandimprovedPCboardlayout.Start-upisincludepowerfactorcorrection(PFC)inordertoreducecontrolledbyseparatePFCandPWMsoftstartpins.Theinputcurrentandmeetfutureregulatoryrequirements.PWMSoftStartpinisheldlow,disablingthePWMoutputSwitchingpowersuppliesthatincorporateabridgerecti-untilthePFCstageisinregulation.ThePWMwillremainfierfollowedbybulkcapacitancecreateharmoniccur-enabledaslongasthePFCoutputvoltagestaysabove73%rents.Theseharmo……