原标题：Silabs Si3480以太网供电(PoE)管理解决方案

　　Silabs公司的Si3480是电源管理器, 和Si3452以太网供电(PoE)控制器一起使用. Si3480采用引脚编程,可用来选择电源容量,低功率(category 1, 15.4 W)数量以及大功率(category 2, 30 W)端口,端口极性以及检测时序,并提供LED驱动以显示端口状态.不需要软件,也不需要数据隔离,完全和IEEE 802.3 clause 33兼容,主要用在802.11n WAPs, IP电话系统和iPBX,工业动化系统和安全与RFID系统等.本文介绍了Si3480主要特性,功能方框图以及典型应用电路图和8端口电源管理参考设计和评估板.

　　The Si3480 is a power manager intended for use with the Si3452 Power over Ethernet (PoE) controller. The Si3480 enables the use of a smaller, lower cost, and more efficiently-utilized power supply in an unmanaged PoE Power Sourcing Equipment (PSE) system.

　　The Si3452 is capable of delivering over 30 W per port, which means that, in a typical 8-port system, a 240 W power supply would have to be used to avoid overload. Typically, not all ports are used at full power; so, a smaller power supply in the range of 30 to 150 W can be used along with the Si3480 power management controller.

　　The Si3480 power management controller is pin programmed. The pins are used to set the power supply capacity, the number of low power (category 1, 15.4 W), and high power (category 2, 30 W) ports, the port priority, and the detection timing (Alternative A or Alternative B). The Si3480 uses the real time overload and current monitoring capability of the Si3452 to manage power for up to eight ports. Power management is based on actual consumption rather than mere classification in order to supply power to the greatest number of ports.

　　The Si3480 also provides LED drive to indicate port status and drive an LED bar graph display to indicate the power supply capacity in use. If a port is denied power due to power supply capacity limitations, the LED indicators provide a simple and intuitive indication, helping a user recognize and correct the overload situation by rebalancing loads or adding mid-span power injectors to ports that would not otherwise be powered. In case of a port overload, the port is easily re-enabled by disconnecting the Powered Device (PD) and then reconnecting the PD after correcting the overload situation.

　　Si3480主要特性:

　　Enables use of a smaller power supply for a 4 or 8 port PoE system

　　Self-contained solution operates without the need for a host for unmanaged operation

　　No software required

　　No data isolation required

　　Fully compliant with IEEE 802.3 clause 33 for Power over Ethernet including the 802.3at amendment for higher power (30 W category 2 ports)

　　Pin programmable for overall power supply capacity, port power level, port priority, and

　　detection timing

　　LED indication of port status and overall power consumption

　　20-pin Quad flat package (4x4 mm)

　　4x4 mm PCB footprint; RoHS compliant

　　Extended operating temperature range (–40 to +85℃)

　　Si3480应用:

　　Managed and unmanaged switches and routers 48 ports and below Supports high-power PDs, such as:

　　Pan/Tilt/Zoom security cameras

　　802.11n WAPs

　　Multi-band, multi-radio WAPs

　　IP Phone Systems and iPBXs

　　Industrial automation systems

　　Security and RFID systems

　　Power injectors

　　Networked audio

　　Metropolitan area networked WAPs, cameras, and sensors WiMAX, ASN/BTS, and CPE/ODU systems

　　图1.Si3480功能方框图

　　图2.Si3480典型应用电路图

　　8端口电源管理参考设计和评估板

　　The Si3480MS8-KIT is intended for detailed engineering evaluation of the Si3452 in conjunction with the Si3480 8-port Power Manager. It implements a complete mid-span power injector with intelligent power management and LED display. The Si3480 power manager is controlled via jumpers with no software programming required. The design features Two Si3452 devices, an Si3480 power manager, and an Si3500 dc-dc converter to complete the power-managed PSE system.

　　图3.8端口电源管理参考设计和评估板外形图