Linear公司的LTC4266A是四;路PSE控制器,可向LTPoE++兼容的PD提供高达90W的功率,而LTC4266C是完全自动化的PSE系统,能为Type 1 (多达13W) PD供电.其先进的电源管理包括14位电流监测ADC,DAC可编程的限流以及预选端口的多种快速关断.主要用在LTPoE++ PSE交换/路由, LTPoE++ PSE中跨, IEEE 802.3at Type 1 PSE交换/路由以及IEEE 802.3at Type 1 PSE中跨.本文介绍了LTC4266A/LTC4266C主要特性, 网络供电系统框图,以及完整的4端口以太网大功率源框图, 光隔离的I2C总线连接等.

Quad PoE/PoE+/LTPoE++ PSE Controller

The LTCR4266A is a quad Power Sourcing Equipment (PSE) controller capable of delivering up to 90W of LTPoE++ power to a compatible LTPoE++ Powered Device (PD). A proprietary detection/classification scheme allows mutual identification between a LTPoE++ PSE and LTPoE++ PD while remaining compatible and interoperable with existing Type 1 (13W) and Type 2 (25.5W) PDs. The LTC4266A feature set is a superset of the popular LTC4266. These PSE controllers feature low RON external MOSFETs and
0.25Ω sense resistors which are especially important at the LTPoE++ current levels to maintain the lowest possible heat dissipation.

The LTC4266C targets fully automatic PSE systems powering Type 1 (up to 13W) PDs.Advanced power management features include: 14-bit current monitoring ADCs, DAC-programmable current limit, and versatile quick shutdown of preselected ports.Advanced power management host software is available under a no-cost license. PD Discovery uses a proprietary dual-mode 4-point detection mechanism ensuring excellent immunity from false PD detection. The LTC4266 includes an I2C serial interface operable up to 1MHz.

The LTC4266 is available in multiple power grades allowing delivered PD power of 13W, 25W, 35W, 45W, 70W and 90W. These controllers are available in a 38-pin 5mm ×7mm QFN package.

LTC4266A/LTC4266C主要特性:

Four Independent PSE Channels

Compliant with IEEE 802.3at Type 1 and 2

Low Power Dissipation

0.25Ω Sense Resistance Per Channel

Very High Reliability 4-Point PD Detection

2-Point Forced Voltage

2-Point Forced Current

High Capacitance Legacy Device Detection

1MHz I2C Compatible Serial Control Interface

Midspan Backoff Timer

Supports 2-Pair and 4-Pair Output Power

Available in Multiple Power Grades

LTC4266A-1: LTPoE++™ 35W

LTC4266A-2: LTPoE++ 45W

LTC4266A-3: LTPoE++ 70W

LTC4266A-4: LTPoE++ 90W

LTC4266C: PoE 13W

Available in 38-Pin 5mm × 7mm QFN Package

LTC4266A+LTC4266C应用:

LTPoE++ PSE Switches/Routers

LTPoE++ PSE Midspans

IEEE 802.3at Type 1 PSE Switches/Routers

IEEE 802.3at Type 1 PSE Midspans

图1.网络供电系统框图

图2.完整的4端口以太网大功率源框图

图3.正VDD升压转换器

图4.光隔离的I2C总线连接图