TLK2201A: Protection to non PoE Ethernet PHY with PoE connection

Govindaraj Rao

Part Number: TLK2201A

Dear Sir,

    We have a custom board which uses 2 Ethernet ports.
    My concern is

    1. What happens if we connect a PoE output port of a switch to this non PoE Ethernet PHY ?
    2. What happens to the current that flows to the PHY ?
    3. Does this damages the Ethernet PHY ?
    4. Let us also consider a case of passive PoE switch where PD detection mechanism is not present. What happens in that case ?

    Can you please guide me in this regard and clear the doubt in the safety of IC ?

Thanks and regards,
Govindaraj

over 8 years ago

0 Luis Omar Moran over 8 years ago

TI__Genius 16150 points

Hi Govindaraj,

You can connect PoE device to non PoE device since the PoE detection occurs in order to avoid damage to non-PoE devices, a key componente of the 802.3af PoE standard detection. PSEs must be able to detect the presence of a PoE-enabled device before sending power, and must be able to detect when the powered device is no longer present and remove power. To achieve accurate detection, a low-level detection current is sent from the PSE through the cable and the response is analyzed to determine if a compliant device is attached.

I hope this helps.

Best Regards,
Luis Omar Moran
High Speed Interface
SWAT Team

0 Govindaraj Rao over 8 years ago in reply to Luis Omar Moran

Prodigy 20 points

Hello Luis Omar Moran,

Thank you very much for this valuable information.

But what happens in a case where passive PoE switch is connected to the non PoE Ethernet port where PD (Power Device) detection mechanism is not present.

Will the PHY gets damaged in that case ?

Thanks and regards,

Govindaraj

Interface

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TLK2201A: Protection to non PoE Ethernet PHY with PoE connection