淺談關(guān)于Silabs Si3471 90W完全自主以太網(wǎng)供電(PoE)解決方案

Silabs公司的Si3471是完全自主以太網(wǎng)供電(PoE)的供電設(shè)備(PSE)器件.完全和IEEE 802.3bt兼容,并和 IEEE 802.3af與802.3at兼容.最適合用于PSE中跨和不需要主MCU的集電器.Si3471集成了IEEE要求的供電設(shè)備(PD)檢測(cè)和分類功能的以太網(wǎng)端口.此外,它還具有采用DC檢測(cè)算法和功能強(qiáng)大的多點(diǎn)檢測(cè)算法的供電設(shè)備(PD)斷開(kāi).智能保護(hù)電路包括輸入欠壓檢測(cè),輸出電流限制和短路保護(hù).Si3471能自主工作,不需要外接主MCU或MCU控制,所有的電源重置和欠壓復(fù)位電路都在器件內(nèi)部.工作溫度–40℃ 到+85℃,38引腳 5 x 7 mm QFN封裝(RoHS兼容),主要用在IEEE 802.3af, 802.3at和802.3bt供電設(shè)備(PSE),以太供電集電器,單端口中跨,以太網(wǎng)交換機(jī)供電,IP電話系統(tǒng),智能電網(wǎng)交換,加固和工業(yè)交換. 中電網(wǎng)為您整理如下詳細(xì)資料,本文介紹了Si3471A主要特性,功能框圖,應(yīng)用框圖以及90W以態(tài)網(wǎng)端口評(píng)估板EVB主要特性,包括基板和子板的電路圖表,材料清單和PCB設(shè)計(jì)圖.

The Si3471 is a fully autonomous Power over Ethernet (PoE) Power Sourcing Equipment (PSE) device. It is fully IEEE 802.3bt compliant and compatible with IEEE 802.3af and 802.3at. It is optimized for use in PSE mid-spans and injectors that do not require a host or MCU. The Si3471 integrates one Ethernet port with the IEEE-required powered device (PD) detection and classification functionality. In addition, it features powered device (PD) disconnect using dc sense algorithms and a robust multipoint detection algorithm. Intelligent protection circuitry includes input undervoltage detection, output current limit, and short-circuit protection. The Si3471 works autonomously and does not require a host or MCU to program it. The Si3471 is programmed for maximum available power by pulling its configration pins high or low.

The Si3471 operates autonomously, without any external host or MCU control. All power on reset and brownout reset circuitry is internal.

Upon VDD and VDDA being applied, an internal pull up sets the RESETb pin high, releasing the Si3471 from reset. The Si3471 thenreads the PWRAVL pins and configures itself to grant the maximum class set by the PWRAVL pins. The multi-point detection algorithmruns until a valid PoE PD signature is detected and then proceeds with classification. If the Si3471 is configured to grant the class thePD requests, it internally sets the current limit to the class requested by the PD and proceeds to grant power. Otherwise, the Si3471follows the IEEE 802.3bt specification for power demotion. The Si3471 automatically detects when a PD disconnects and restarts thedetection process, continuously looking for a valid detection signature. If any error or fault condition occurs, the Si3471 removes powerfrom the PD and automatically restarts the detection process.

The Si3471 includes an LED pin for driving a status indicator LED. If a status LED is not used, then the pin can be left floating. The LEDoperation is shown in the table below and is not configurable.

Si3471A主要特性:

? Single Ethernet port PoE Power SourcingEquipment (PSE) device
? IEEE 802.3bt compliant
? IEEE 802.3af and 802.3at compatible
? Multi-point detection
? Comprehensive fault protection circuitryincludes:
? Power undervoltage lockout
? Output current limit and short-circuitprotection
? Thermal overload detection
? Operating temp range: –40℃ to +85℃
?38-pin 5 x 7 mm QFN package (RoHScompliant)

Si3471A應(yīng)用:

? IEEE 802.3af, 802.3at, and 802.3bt Power Sourcing Equipment (PSE)
? Power over Ethernet Injectors
? Single Port Mid-Spans
? Power over Ethernet Switches
? IP Phone Systems
? Smartgrid Switches
? Ruggedized and Industrial Switches

圖1.Si3471功能框圖

圖2.Si3471典型802.3bt應(yīng)用框圖

圖3.Si3471典型802.3bt中跨應(yīng)用框圖

90W以態(tài)網(wǎng)端口評(píng)估板EVB

Si3471 Single 90 W Ethernet Port EVB

The Si3471 is a fully autonomous 802.3bt PSE capable of supplying 90 W on a single PoE Ethernet port. Three static I/O pins configure the maximum power the Si3471 will grant to a connected PD. The Si3471 includes a built-in LED driver to indicate the status of the PoE Ethernet port.

Configured as a single Ethernet port mid-span, the Si3471 EVB provides easy access to all Si3471 features. The compact design includes a two-layer daughtercard and a twolayerbaseboard. Both are excellent starting points for new Si3471 designs.

90W以態(tài)網(wǎng)端口評(píng)估板EVB主要特性:

? Adds 90 W PoE to a non-poweredEthernet cable
? Configurable max power output andaccess to Si3471 features
? Small, simple, two layer PCBs
? Only 1.8 x 3.25 inches, 46 x 83 mm
? IEEE 802.3bt compliant
? 54 V, 90 W power supply included

圖4.90W以態(tài)網(wǎng)端口評(píng)估板EVB外形圖

圖4. Si3471 EVB子板外形圖

圖5. Si3471 EVB基板外形圖

圖6.子板電路圖

圖7.基板電路圖

圖8.子板PCB設(shè)計(jì)圖:頂層絲印

圖9.子板PCB設(shè)計(jì)圖:底層絲印

圖10.子板PCB設(shè)計(jì)圖:頂層布局

圖11.子板PCB設(shè)計(jì)圖:底層布局

圖12.基板PCB設(shè)計(jì)圖:頂層絲印

圖13.基板PCB設(shè)計(jì)圖:頂層布局

圖14.基板PCB設(shè)計(jì)圖:底層布局
Si3471子板材料清單:

Si3471母板材料清單: