原标题：Silabs Si3406x系列以太网供电+(PoE+)解决方案

　　Silabs公司的Si3406x系列是符合IEEE 802.3要求的全集成式PoE+ PD 接口和带晶体管旁路以及睡眠,唤醒和 LED 驱动器的高效率开关稳压器,集成了以太网供电+(PoE+)型供电设备(PD) 应用中所需的所有电源管理和控制功能,完全支持 IEEE 802.3at 规范,能够进行单个或两个事件分类.主要用在 IP 语音电话,无线接入点,安保和监察 IP 摄像机,照明设备,销售点终端机,以太网设备和网络设备.本文介绍了Si3406x系列主要特性,框图,应用电路以及评估板Si34061ISOC4-KIT主要特性,电路图,材料清单和PCB设计图.

　　Si3406x 产品系列集成了以太网供电+(Power-over-Ethernet Plus，PoE+)型供电设备(PD) 应用中所需的所有电源管理和控制功能。设备将通过 10/100/1000BASE-T 以太网连接供应的输入高电压转换成稳定低压输出电源。该设备产品系列的优化体系结构能够最大程度地减小解决方案的体积和外部物料清单 (BOM) 成本，同时支持使用低成本外部元件并保持高性能。Si3406x 产品系列集成了所需的二极管电桥和瞬态浪涌抑制器，支持将集成电路 (IC) 直接连接到以太网 RJ-45 连接器。此外，还集成了开关电源 FET和所有相关功能。这个集成的、由电流模式控制的开关稳压器支持隔离或非隔离回扫和降压转换器拓扑。可以通过简单的外部电阻值调谐稳压器的切换频率，避免不必要的谐波，以实现更好的辐射控制。同步驱动器用于对次级侧 FET 进行选择性驱动，以提高电源转换的效率。通过可选自动维持功率特征 (MPS) 信号，可以在睡眠期间保持与 PSE开关的连接。

　　此类设备完全支持 IEEE 802.3at 规范，能够进行单个或两个事件分类。标准外部电阻为探测功能和分类模式的编程提供了合适的 IEEE 802.3 签名，内部启动电路确保热插拔开关和稳压器都具有控制良好的软启动初始操作。

　　Si34061 和 Si34062 添加了主变压器偏压线圈支持，可确保超高效操作。Si34061 支持外部扩充或内部热插拔和/或切换 FET 的完全旁路，有助于最大程度地改善在 Class 4 高端应用中的功率容量和散热管理，还可在有需要时进一步提高电源转换效率。

　　Si34062 支持睡眠模式、唤醒功能以及 LED 驱动能力。这些功能可用于最大程度地减少待机电流、控制睡眠和唤醒状态，还可以利用固态或闪烁 LED 提供应用状态信息。Si3406 采用薄型、20 引脚、5 x 5 mm QFN 封装，Si34061 和 Si34062 采用薄型、24引脚、5 x 5 mm QFN 封装。

　　主要特点

　　1 类 (PoE) 或 2 类 (PoE+) 电源

　　完全符合 IEEE 802.3at 要求

　　同步辅助 FET 驱动器

　　电流模式直流-直流转换器

　　可调谐切换频率

　　辅助变压器线圈支持

　　辅助适配器支持

　　内部热插拔和切换 FET 旁路支持

　　自动维持功率特征 (MPS) 支持

　　支持睡眠模式，还扩展了唤醒引脚、模式控

　　制和 LED 驱动器支持

　　120 V 绝对最大电压性能

　　扩展的温度范围(–40°C 至 +85°C)

　　紧凑型、符合 ROHS 要求的 5 mm x 5 mm

　　QFN 封装

　　应用

　　IP 语音电话

　　无线接入点

　　安保和监察 IP 摄像机

　　照明设备

　　销售点终端机

　　以太网设备

　　网络设备

　　The Si3406x family integrates all power management and control functions required ina Power-over-Ethernet Plus (PoE+) powered device (PD) application. These devicesconvert the high voltage supplied over the 10/100/1000BASE-T Ethernet connection toa regulated, low-voltage output supply. The optimized architecture of this device familyminimizes the solution footprint and external BOM cost and enables the use of low-cost

　　external components while maintaining high performance. The Si3406x family integrates the required diode bridges and transient surge suppressor, thus enabling directconnection of the IC to the Ethernet RJ-45 connector. The switching power FET and all associated functions are also integrated. The integrated, current mode controlledswitching regulator supports isolated or non-isolated flyback and buck converter topologies.

　　The switching frequency for the regulator is tunable with a simple external resistorvalue to help avoid unwanted harmonics for better emissions control. A synchronousdriver is provided to optionally drive a secondary side FET to improve efficiency of powerconversion. Connection to the PSE switch is maintained during sleep by an optional automated maintain-power-signature (MPS) signal.

　　These devices fully support the IEEE 802.3at specification for the cases of single ortwo event classification. Standard external resistors provide the proper IEEE 802.3 signatures for the detection function and programming of the classification mode, and internalstartup circuits ensure well-controlled soft-start initial operation of both the hotswapswitch and the voltage regulator.

　　The Si34061 and Si34062 add main transformer bias winding support for ultra-high-efficiencyoperation.

　　The Si34061 includes support for external augmentation or full bypass of the internalhotswap and/or switching FET for best power handling and thermal management at the high end of Class 4, plus offers a further boost in power conversion efficiency whenneeded.

　　The Si34062 includes support for sleep modes with wake function, as well as LED drive capability. These features can be utilized to minimize standby current, control sleepand wake states, and provide application status information using a solid or blinkingLED.

　　The Si3406 is available in a low-profile, 20-pin, 5 x 5 mm QFN package, and theSi34061 and Si34062 are available in low-profile, 24-pin, 5 x 5 mm QFN packages.

　　Si3406x系列主要特性:

　　• Type 1 (PoE) or Type 2 (PoE+) power

　　• Full IEEE 802.3at compliance

　　• Synchronous secondary FET driver

　　• Current mode dc-dc converter

　　• Tunable switching frequency

　　• Auxiliary transformer winding support

　　• Auxiliary adapter support

　　• Internal hotswap and switching FET bypasssupport

　　• Automated maintain-power-signature (MPS)support

　　• Sleep mode augmented with wake pin,mode control, and LED driver

　　• 120 V Absolute Max voltage performance

　　• Extended –40 to +85 ℃ temperature

　　• Compact ROHS-compliant 5 mm x 5 mmQFN Package

　　Si3406x系列应用:

　　• Voice over IP telephones

　　• Wireless access points

　　• Security and surveillance IP cameras

　　• Lighting luminaires

　　• Point-of-sale terminals

　　• Internet appliances

　　• Network devices

　　评估板Si34061ISOC4-KIT

　　This Si34061-ISO-FB EVB maximum output level is Class 4 power (η x 30 W).The Si34061-ISO-FB EVB is shown below. The Si34061 IC integrates an IEEE 802.03at compatiblePoE+ interface as well as a current control based dc/dc converter.

　　The Si34061 PD integrates two diode bridges, which can be used up to 200 mA input current, detection circuit, classification circuit, dc/dc switch, hot-swap switch, TVS overvoltageprotection, dynamic soft-start circuit, cycle-by-cycle current limit, synchronous gate driver, bias winding option, maintain power signature (MPS), thermal shutdown and inrush current protection.

　　Beyond this, to improve thermal and power performance Si34061 integrates a driver foran external hot swap switch, as well as a driver for a primary dc/dc switch.

　　To improve efficiency, the Si34061 can be driven from an auxiliary bias winding. Besides a PoE input, the Si34061 is capable of running from an external wall adapterwith a minimum voltage of 12 V.

　　The switching frequency of the converter is tunable by an external resistor.

　　评估板Si34061ISOC4-KIT主要特性:

　　• IEEE 802.03at Compatible

　　• High Efficiency

　　• High Integration

　　• Optional MPS Function

　　• External Primary Switch Driver

　　• External HSSW Driver

　　• Auxiliary Bias Winding Support

　　• Wall Adapter Support from 12 V

　　• Synchronous Gate Driver

　　• High Flexibility

　　• Transient Overvoltage Protection

　　• Thermal Shutdown Protection

　　• 5x5 mm 24-pin QFN

　　图.评估板Si34061ISOC4-KIT外形图

　　评估板Si34061ISOC4-KIT材料清单:

　　详情请见:

si3406x-datasheet.pdf

ug333-si34061isoc4evb.pdf