基于PD69101设计的混合信号高压以太网供电方案

Microsemi公司的PD69101是单端混合信号高压以太网供电(PoE)驱动器,它采用以太网开关和使能网络器件在同一电缆上共享电源和数据,能检测EEE802.3af-2003兼容的受电设备(PD)和IEEE802.3at大功率设备.DC输入电压44 - 57 VDC,内置了3.3V DC稳压器,工作温度从-40°到+85℃,具有超温保护和电压监视与保护等.本文介绍PD69101主要特性,方框图以及2对和4对(数据和供电)典型应用电路图.

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


图1.PD69101内部方框图

图2.PD69101典型的2对应用电路图

图3.PD69101典型的4对应用电路图