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TPS2372: TPS2372-4

avi sarussi
Prodigy 20 points
Part Number: TPS2372

Hi 

On our base station we have PD TPS2372-4RGW with Ls1046A CPU and Aquantia Phy .we have two assembly options:

        1 support class 4 up to 30W RCLS1 63.4 ohm and RCLS2 63.4 ohm

  1. support class 5 up to 45W RCLS1 63.4 ohm and RCLS2 1.21K ohm.

In case that we want to unify assembly and both assemblies will be hardware mounted as 30W ( RCLS1 63.4 ohm and RCLS2 63.4 ohm) do we have 

the option to increase power higher than 30W via LLDP protocol.

If yes what are the required hardware changes ?

I guess that TPH , TPL and BT pins should be connected to my host (NXP LS1046A) and add the LLDP protocol to run on the Ls1046A

Additional question:

1.I saw that there is Auto class pin that we left opened since on the past we saw that it limit our power (probably because we don't have LLDP)

2.since we don't know what type of PSE will connect to our units (it can be Cisco or other many switches) do you see any issue with that? Like interoperability problems etc.?

3 Does the LLDP can work whenever I want to provide more power to my PD (By sending message from PD to PSE) or it is limited on the start sessions?

As I understand the mechanism will be as following:

  1. PSE power up my PD at 30W (class 4) than after while our PD ask from PSE via LLDP to increase power lets say to class 5.is it the correct process?

PoE schematics attached

Many Thanks 

Avi

  • 0
    TI__Intellectual 1480 points

    Hello Avi, 

    Regarding,

    "In case that we want to unify assembly and both assemblies will be hardware mounted as 30W ( RCLS1 63.4 ohm and RCLS2 63.4 ohm) do we have the option to increase power higher than 30W via LLDP protocol."

    No, you cannot increase power higher than 30W over LLDP in this case. Once the PSE has assigned the PD as class 4, you would be bounded to the maximum power for class 4 PoE PD. Also keep in mind that the power requested over LLDP does not account for cable loss.

    Regarding,

    "Questions 1 and 2" 

    I do not see any issues with leaving the autoclass enable pin open. 

    Regarding,

    "3 Does the LLDP can work whenever I want to provide more power to my PD (By sending message from PD to PSE) or it is limited on the start sessions?"

    Typically you can configure LLDP requested power anytime after classifying and powering on the PD. The actual implementation and limitations may vary by PSE and system design. 

    Regarding,

    "PSE power up my PD at 30W (class 4) than after while our PD ask from PSE via LLDP to increase power lets say to class 5.is it the correct process?"

    This is not possible because of the handshake mechanism required by IEEE 802.3af, at, bt standard. To go up to a higher power class, you would need to disconnect the PD then redo detection and classification. However this would require different classification resistors so you can see why it is not possible. 

    Regards,

    Sai Gunda 

  • 0 in reply to Sai Gunda
    Prodigy 20 points

    Thanks for the clear answer

  • 0 in reply to avi sarussi
    TI__Intellectual 1480 points

    You're welcome. I will close the thread but don't hesitate to respond with future questions. 

    Regards,

    Sai Gunda