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Linear公司的LT3798是絕緣無光耦帶PFC的反激控制器,功率因素大于0.97,不需要光耦合器,諧波低,恒流和恒壓調整,精度在±5%,無負載的功耗小于0.5W,和能源之星標準兼容,主要用在離線5W-100W電源,高DC VIN絕緣應用和離線總線轉換器(12V,24V或48V輸出).本文介紹了LT3798主要特性,框圖以及通用輸入24W和48W PFC電源電路圖. Isolated No Opto-Coupler Flyback Controller with Active PFC The LT®3798 is a constant voltage/constant current isolated flyback controller that combines active power factor correction (PFC) with no opto-coupler required for output voltage feedback into a single-stage converter. A LT3798 based design can achieve a power factor of greater than 0.97 by actively modulating the input current, allowing compliance with most Harmonic Current Emission requirements. The LT3798 is well suited for a wide variety of off-line applications. The input range can be scaled up or down, depending mainly on the choice of external components. Efficiencies higher than 86% can be achieved with output power levels up to 100 watts. In addition, the LT3798 can easily be designed into high DC input applications. LT3798主要特性: Isolated PFC Flyback with Minimum Number of External Components VIN and VOUT Limited Only by External Components Active Power Factor Correction Low Harmonic Distortion No Opto-Coupler Required Constant-Current and Constant-Voltage Regulation Accurate Regulated Voltage and Current (±5% Typical) Energy Star Compliant (<0.5W No Load Operation) Thermally Enhanced 16-lead MSOP Package LT3798應用: Offline 5W to 100W+ Applications High DC VIN Isolated Applications Offline Bus Converter (12V, 24V or 48V Outputs) 
圖1. LT3798方框圖
圖2. LT3798通用輸入24W PFC總線電源電路圖
圖3. LT3798通用輸入48W PFC電源電路圖 詳情請見: 
3798p[1].pdf
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