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NS LM3152 12A开关电源控制方案

关键词:电源管理 AC/DC转换器 LM3151/2/3

时间:2009-07-16 17:53:00       来源:NS

NS公司的LM3151/2/3 是SIMPLE SWITCHER ®控制器,能为降压稳压器提供高达12A的输出电流,输入电压从6V到42V,输出电压3.3V,开关频率250 kHz, 500 kHz和750 kHz,不需要回路补偿.可用于高性能DSP,FPGA,ASIC和微处理器,宽带,网络和光纤通信基础设备,路由器,安全监视和电源模块.本文介绍了LM3151/2/3的主要特性, 方框图以及演示板电路图和演示板材料清单(BOM).

The LM3151/2/3 SIMPLE SWITCHER ® Controller is an easy to use and simplified step down power controller capable of providing up to 12A of output current in a typical application. Operating with an input voltage range of 6V-42V, the LM3151/2/3 features a fixed output voltage of 3.3V, and features switching frequencies of 250 kHz, 500 kHz, and 750 kHz. The synchronous architecture provides for highly efficient designs. The LM3151/2/3 controller employs a Constant On-Time (COT) architecture with a proprietary Emulated Ripple Mode (ERM) control that allows for the use of low ESR output capacitors, which reduces overall solution size and output voltage ripple. The Constant On-Time (COT) regulation architecture allows for fast transient response and requires no loop compensation, which reduces external component count and reduces design complexity.

Fault protection features such as thermal shutdown, under-voltage lockout, over-voltage protection, short-circuit protection, current limit, and output voltage pre-bias startup allow for a reliable and robust solution.

The LM3151/2/3 SIMPLE SWITCHER  concept provides for an easy to use complete design using a minimum number of external components and National’s WEBENCH  online design tool. WEBENCH  provides design support for every step of the design process and includes features such as external component calculation with a new MOSFET selector, electrical simulation, thermal simulation, and Build-It boards for prototyping

主要特性:
PowerWise  step-down controller
6V to 42V Wide input voltage range
Fixed output voltage of 3.3V
Fixed switching frequencies of 250 kHz/500 kHz/750 kHz
No loop compensation required
Fully WEBENCH  enabled
Low external component count
Constant On-Time control
Ultra-Fast transient response
Stable with low ESR capacitors
Output voltage pre-bias startup
Valley current limit
Programmable soft-start

应用:
High Performance DSPs, FPGAs, ASICs and microprocessors
Broadband, Networking and Optical Communications Infrastructure
Routers
Security Surveillance
Power Modules



图1.LM3151/2/3方框图

LM3152-3.3演示板

The LM3152-3.3 demonstration board is part of the Power-Wise  family of SIMPLE SWITCHER  Controllers. It has been designed to balance solution size and  performance.
The Constant-On-Time (COT) Emulated Ripple Mode (ERM) Control allows for the use of low ESR output capacitors and therefore decreases the output voltage ripple while maintaining a fast transient response. There is no loop compensation required for the COT architecture, as there is in voltage-mode and current mode control architectures, which helps to facilitate the ease of design and fast transient response. The demo board uses a 2-layer, 2 ounce copper PCB with all of the components mounted on the top side. The LM3152-3.3 IC has a fixed output voltage of 3.3V and will operate over the input voltage range of 6V to 24V at 10A load current. The components within the dashed line of the board photo in Figure 2, represent the total design solution. The aluminum electrolytic input capacitor Cin1 is used for input filter damping when using long leads, which contributes to parasitic inductance in the lab while using the demo board. Cin1 along with
the input/output posts and EN test point connector may not be needed when the final circuit is integrated in the system design.

LM3152-3.3演示板主要特性:
■ Easy To Use with Webench and Offline Design Tools
■ No Loop Compensation Required
■ Low Solution Component Count
■ Ultra-Fast Transient Response
■ Low Output Voltage Ripple (32mVpp)
■ 3.3V Fixed Output Voltage
■ Optimized for 10A Average Load Current
■ 95% Peak Efficiency
■ Constant-On-Time with Emulated Ripple Mode Control
■ 500kHz Switching Frequency



图2.LM3152-3.3演示板外形图



图3.LM3152-3.3演示板电路图

LM3152-3.3演示板材料清单(BOM):



详情请见:
http://www.national.com/ds/LM/LM3151.pdf

http://www.national.com/cgi-bin/rdpdf.cgi/RD-164.pdf
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