TI公司的UCC28950是具有同步整流的绿色相移全桥控制器,能把370V-410VDC的输入电压转换成12V稳压输出.初级信号可编程延迟以保证ZVS在宽负载电流和输入电压内工作,而负载电流能调整次级同步整流开关延迟以最大化系统效率,并能对多个轻负载进行管理,主要用在相移全桥转换器,服务器,通信电源,工业电源,高密度电源架构以及太阳能逆变器和电动汽车.本文介绍了UCC28950主要特性,方框图, 典型应用框图以及评估板UCC28950EVM-442主要特性, 效率测试连接图,电路图和材料清单.

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

V_DD Under Voltage Lockout

Wide Temperature Range –40°C to 125°C

UCC28950应用:

Phase-Shifted Full-Bridge Converters

Server, Telecom Power Supplies

Industrial Power Systems

High-Density Power Architectures

Solar Inverters, and Electric Vehicles

图1. UCC28950方框图

图2. UCC28950典型应用框图

评估板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

评估板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

评估板UCC28950EVM-442典型应用:

• Server, Telecom Power Supplies

• Industrial Power Systems

• High-Density Power Architectures


图3.评估板UCC28950EVM-442功率级电路图

图4.评估板UCC28950EVM-442子板控制卡电路图

图5.评估板UCC28950EVM-442效率测试连接图

图6.评估板UCC28950EVM-442评估电压回路和ZVS的连接图
评估板UCC28950EVM-442材料清单:


评估板UCC28950EVM-442子板材料清单:

详情请见:
http://www.ti.com/lit/ds/slusa16a/slusa16a.pdf
和
http://www.ti.com/lit/ug/sluu421a/sluu421a.pdf