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TI公司的UCC28950是具有同步整流的綠色相移全橋控制器,能把370V-410VDC的輸入電壓轉換成12V穩壓輸出.初級信號可編程延遲以保證ZVS在寬負載電流和輸入電壓內工作,而負載電流能調整次級同步整流開關延遲以最大化系統效率,并能對多個輕負載進行管理,主要用在相移全橋轉換器,服務器,通信電源,工業電源,高密度電源架構以及太陽能逆變器和電動汽車.本文介紹了UCC28950主要特性,方框圖, 典型應用框圖以及評估板UCC28950EVM-442主要特性, 效率測試連接圖,電路圖和材料清單. Green Phase-Shifted Full-Bridge Controller With Synchronous Rectification The UCC28950 enhanced phase-shifted controller builds upon Texas Instrument’s industry standard UCCx895 phase-shifted controller family with enhancements that offer best in class efficiency in today’s high performance power systems. The UCC28950 implements advanced control of the full-bridge along with active control of the synchronous rectifier output stage. The primary-side signals allow programmable delays to ensure ZVS operation over wide-load current and input voltage range, while the load current naturally tunes the secondary-side synchronous rectifiers switching delays, maximizing overall system efficiency. The UCC28950 also offers multiple light-load management features including burst mode and dynamic SR on/off control when transitioning in and out of Discontinuous Current Mode (DCM) operation, ensuring ZVS operation is extended down to much lighter loads. UCC28950主要特性: Enhanced Wide Range Resonant Zero Voltage Switching (ZVS) Capability Direct Synchronous Rectifier (SR) Control Light-Load Efficiency Management Including Burst Mode Operation Discontinuous Conduction Mode (DCM), Dynamic SR On/Off Control with Programmable Threshold Programmable Adaptive Delay Average or Peak Current Mode Control with Programmable Slope Compensation and Voltage Mode Control Closed Loop Soft Start and Enable Function Programmable Switching Frequency up to 1 MHz with Bi-Directional Synchronization (+/–3%) Cycle-by-Cycle Current Limit Protection with Hiccup Mode Support 150-µA Start-Up Current VDD Under Voltage Lockout Wide Temperature Range –40°C to 125°C UCC28950應用: Phase-Shifted Full-Bridge Converters Server, Telecom Power Supplies Industrial Power Systems High-Density Power Architectures Solar Inverters, and Electric Vehicles 
圖1. UCC28950方框圖
圖2. UCC28950典型應用框圖 評估板UCC28950EVM-442 The UCC28950EVM-442 is a 600-W phase-shifted full-bridge converter that converts a 370 V to 410-V DC input to a regulated 12-V output. This converter was designed to maintain ZVS down to 50% load. This 600-W EVM was designed to demonstrate how the UCC28950 control device could be used in high-efficiency applications by achieving ZVS from 50% to 100% load. To achieve this high efficiency the UCC28950 was designed to drive synchronous rectifiers on the secondary side of the full bridge converter. The UCC28950 also incorporates a burst mode and DCM function to improve no-load efficiency 評估板UCC28950EVM-442主要特性: ZVS from 50% to 100% load Higher Efficiency for 80 + Applications Burst Mode/DCM Function to Reduce No-Load Power Dissipation to Meet Green-Mode Requirements 評估板UCC28950EVM-442典型應用: • Server, Telecom Power Supplies • Industrial Power Systems • High-Density Power Architectures
圖3.評估板UCC28950EVM-442功率級電路圖
圖4.評估板UCC28950EVM-442子板控制卡電路圖
圖5.評估板UCC28950EVM-442效率測試連接圖
圖6.評估板UCC28950EVM-442評估電壓回路和ZVS的連接圖 評估板UCC28950EVM-442材料清單:
評估板UCC28950EVM-442子板材料清單:
詳情請見: http://www.ti.com/lit/ds/slusa16a/slusa16a.pdf 和 http://www.ti.com/lit/ug/sluu421a/sluu421a.pdf |
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