NS LM25066带PMBus接口的热插拔控制方案

发布时间：2011-9-29 15:27 发布者：Liming

NS公司的LM25066集成了兼容SMBus/I2C的PMBus接口和高性热插拔控制器,可精确测量,保护和控制计算机和存储的电工作条件.输入电压范围2.9V-17V,可编程25mV或46mV电流阈值,电流测量精度±2.4%,功率测量精度±3.0%,能以12位分辨率和1kHz取样速率实时监视VIN, VOUT, IIN, PIN, VAUX电压,主要用于服务器背板系统,基站电源分配系统和固态电路断路器.本文介绍了LM25066主要特性, 方框图, 典型应用电路图以及评估板LM25066EVK电路图,材料清单和PCB元件布局图.

The LM25066 combines a high performance hot-swap controller with a PMBus™ compliant SMBus/I2C interface to accurately measure, protect and control the electrical operating conditions of computing and storage blades connected to a backplane power bus. The LM25066 continuously supplies real-time power, voltage, current, temperature and fault data to the system management host via the SMBus interface.

The LM25066 control block includes a unique hot-swap architecture that provides current and power limiting to protect sensitive circuitry during insertion of boards into a live system backplane, or any other "hot" power source. A fast acting circuit breaker prevents damage in the event of a short circuit on the output. The input under-voltage and over-voltage levels and hysteresis are configurable, as well as the insertion delay time and fault detection time. A temperature monitoring block on the LM25066 interfaces with a low-cost external diode for monitoring the temperature of the external MOSFET or other thermally sensitive components. The POWER GOOD output provides a fast indicator when the input and/or output voltages are outside their programmed range. LM25066 current measurement accuracy is ±2.4% over temperature.

The LM25066 monitoring block computes both the real-time and average values of subsystem operating parameters (VIN, IIN, PIN, VOUT) as well as the peak power. Accurate power averaging is accomplished by averaging the product of the input voltage and current. A black box (Telemetry/Fault Snapshot) function captures and stores telemetry data and device status in the event of a warning or a fault.

LM25066主要特性:

■ Input voltage range: 2.9V to 17V

■ I2C/SMBus interface and PMBus™ compliant command structure

■ Programmable 25mV or 46mV current limit threshold

■ Configurable circuit breaker protection for hard shorts

■ Configurable under- and over-voltage lockouts with hysteresis

■ Remote temperature sensing with programmable warning and shutdown thresholds

■ Detection and notification of damaged MOSFET condition

■ Real time monitoring of VIN, VOUT, IIN, PIN, VAUX with 12-bit resolution and 1 kHz sampling rate

■ Current measurement accuracy: ±2.4% over temperature

■ Power measurement accuracy: ±3.0% over temperature

■ True input power measurement using simultaneous sampling of VIN and IIN accurately averages dynamic power readings

■ Averaging of VIN, IIN, PIN, and VOUT over programmable interval ranging from 0.001 to 4 seconds

■ Programmable WARN and FAULT thresholds with SMBA notification

■ Blackbox capture of telemetry measurements and device status triggered by WARN or FAULT condition

■ Full-featured application design and development GUI

■ 24-lead LLP package

LM25066应用:

■ Server backplane systems

■ Basestation power distribution systems

■ Solid state circuit breaker

图1. LM25066方框图

图2. LM25066典型应用电路图

评估板LM25066EVK

The LM25066EVK evaluation kit provides the design engineer with a fully functional, intelligent monitoring and hotswap protection board designed for positive voltage systems.

This application note describes the various functions of the evaluation board, how to test and evaluate it, and how to use the companion GUI. The GUI is used to collect telemetry,configure warning and fault thresholds, and assist the designer with selection of the external components for a specific application. Use of the advanced telemetry and monitoring capabilities of the LM25066 requires external control via the PMBus™ interface. However, the LM25066 is capable of acting as a hot-swap and protection circuit without any PMBus™ intervention. Please check the LM25066 webpage for the latest software and datasheet information.

评估板LM25066EVK主要特性:

• Input voltage range: 2.9V to 16V (limited by input clamp D1)

• Programmable current limit: set to 50A (±8%)

• Q1 power limit: 80W (typical)

• UVLO thresholds: 2.9V and 3.1V

• PGD thresholds: 10.8V and 10.25V

• Insertion delay: 147 ms (typical)

• Fault time-out period: 8.9 ms

• Restart time: 1.1 seconds

• PCB size: 3.5” x 4.2”

• Solution size: 0.7” x 0.7”