基于PD69101設計的混合信號高壓以太網供電方案

Microsemi公司的PD69101是單端混合信號高壓以太網供電(PoE)驅動器,它采用以太網開關和使能網絡器件在同一電纜上共享電源和數據,能檢測EEE802.3af-2003兼容的受電設備(PD)和IEEE802.3at大功率設備.DC輸入電壓44 - 57 VDC,內置了3.3V DC穩壓器,工作溫度從-40°到+85℃,具有超溫保護和電壓監視與保護等.本文介紹PD69101主要特性,方框圖以及2對和4對(數據和供電)典型應用電路圖.

Microsemi’s PD69101 is a single port, mixed-signal, high-voltage Power over Ethernet driver. The device is utilized in Ethernet switches and enables network devices to share power and data over the same cable. It enables detection of IEEE802.3af-2003 compliant PDs (Powered Devices) and IEEE802.3at High Power Devices, thus, ensuring safe power feeding and disconnection of ports with full digital control and a minimum of external components. Integrating power, analog and state of the art logic, the PD69101 device fits into a single 24-pin, plastic QFN package.

A “plug and play” device, the PD69101 executes all real time functions as specified in the IEEE802.3af-2003 (“AF”) and IEEE802.3at High Power (“AT”) standards, including load detection, “AF” and “AT” classification, and using Multiple Classification Attempts (MCA).

The PD69101 :

? Is designed to detect and disable disconnected ports, utilizing DC disconnection methods, as specified in the IEEE 802.3af-2003 and IEEE802.3ar-2009 standards.

? Can optionally detect legacy/pre-standard PD devices.

? Provides PD protection such as over-load, under-load, over-voltage, over-temperature and short-circuiting.

? Supports supply voltages ranging from 44 V to 57 VDC with no need for additional power supply sources.

? Is a low power device using an internal 0.3 Ω MOSFET and an external 0.5 Ω sense resistor.

The chip includes built-in internal thermal protection.

Two LEDs provide port state’s indication and port type (AF/AT).

PD69101主要特性:

Fully IEEE802.3af-2003 and IEEE802.3at-2009 compliant

Includes two-event classification

Supports pre-standard PD detection

Supports Cisco devices detection

Single DC voltage input (44 - 57 VDC)

Supports 2 Pairs and 4 Pairs (Data and Spare Power Feeding)

VMAIN Out of Range Protection

Wide temperature range: -40°to +85℃

Over-temperature protection

Low thermal dissipation (0.5 Ω sense resistor)

Includes on/off command pin

2 x direct LEDs drive

Continuous port monitoring and system data

Configurable load current setting

Configurable AT/AF modes

Configurable standard and legacy detection mode

Power soft start mechanism

On-chip thermal protection

Voltage monitoring & protection

Built in 3.3 VDC regulator

Internal power on reset

RoHS compliant

Low Rdson FET: 0.3 Ω


圖1.PD69101內部方框圖

圖2.PD69101典型的2對應用電路圖

圖3.PD69101典型的4對應用電路圖