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Original question:

Can TPS2373 work with UPoE PSE?

TPS2378: Connect to UPoE PSE

chentsu chung
Mastermind 6180 points
Part Number: TPS2378
Other Parts Discussed in Thread: UCC2897A, TPS23880, TPS23881,

Hi Team,

Our customer can not get power when using TPS2378*2+UCC2897A connect with PoE switch(CISCO Catalyst 9407), and can get power if using PoE injector(POE-173 / PD-9501GR).

I'm not sure CISCO Catalyst 9407 is bt solution or UPoE solution, so...

1. If  CISCO Catalyst 9407 is a UPoE solution, in previous thread, TI mention that there are only two ways to do UPOE. Through LLDP using a single signature PD or through Forced UPOE using a dual signature PD, so can I asume that CISCO's switch useing LLDP to do UPoE and that's why PD(TPS2378) can not get power?

2. follow question1, if not, then what should be the reason?

3. follow question1, if yes, then what can I do for CISCO's switch for geting power? Any setting to modify?

4. If  CISCO Catalyst 9407 is a bt solution, then it will not provide power for UPoE PD (TPS2378*2), am I right?

# The white paper of CISCO's switch for reference:

  https://web.archive.org/web/20171128140727/http:/www.cisco.com/c/en/us/products/collateral/switches/catalyst-4500-series-switches/white_paper_c11-670993.html

 

Best regards,

C.T.

  • 0
    TI__Genius 15665 points

    Hi C.T.,

    In general, UPoE PSE port and BT PSE port should turn on your UPoE PD. 

    1. If  CISCO Catalyst 9407 is a UPoE solution, in previous thread, TI mention that there are only two ways to do UPOE. Through LLDP using a single signature PD or through Forced UPOE using a dual signature PD, so can I asume that CISCO's switch useing LLDP to do UPoE and that's why PD(TPS2378) can not get power?

    [Penny]Even it uses LLDP to negotiate the power, it should turn on one channel first to power up the PD and use LLDP to increase the power level.

    2. follow question1, if not, then what should be the reason?

    [Penny]I don't know the root cause with the limited information. I need more information to dig into the details. Please capture voltage and current waveforms for both pairsets(12&36 and 45&78). 

    3. follow question1, if yes, then what can I do for CISCO's switch for geting power? Any setting to modify?

    [Penny]This would be a question for Cisco as we are not familiar with the hardware and software design. 

    4. If  CISCO Catalyst 9407 is a bt solution, then it will not provide power for UPoE PD (TPS2378*2), am I right?

    [Penny]TPS2378*2 is not a valid BT standard dual signature PD but the PSE should be able recognize the PD as a dual signature PD. TPS23880/TPS23881 can recognize the PD as class 4/class 4 dual signature PD. 

    Best regards,

    Penny

  • 0 in reply to Penny Xu
    Mastermind 6180 points

    Hi Penny,

    Because this is an issue reported from end-customer, so our customer have no CISCO's switch to test with their PD.

    1. Due to TPS2378*2+UCC2897A is design for CISCO's UPoE, so it supose to work well with CISCO's switch, am I right?

    2. Does TI had tested TPS2378*2+UCC2897A with CISCO's UPoE switch while UPoE standard released?

    (I know this is a stupid question, I just make sure for our customer)

    Thanks for your help!

    Best regards,

    C.T.

  • 0 in reply to chentsu chung
    TI__Genius 15665 points


    Hi C.T,

    1. Due to TPS2378*2+UCC2897A is design for CISCO's UPoE, so it supose to work well with CISCO's switch, am I right?

    Yes.

    2. Does TI had tested TPS2378*2+UCC2897A with CISCO's UPoE switch while UPoE standard released?

    I am assigning this question to PD apps to answer your question.

    Thanks,

    Penny

  • 0 in reply to Penny Xu
    TI__Mastermind 40700 points

    Hi CT,

    Have you seen the training video below? There are two approaches to UPOE. Forced UPOE (hardware) and LLDP UPOE (software). The 2x TPS2378 can provide the hardware classification if the UPOE switch is providing Forced UPOE. It can also do LLDP UPOE as long as the PD system (microcontroller on the PD load and NOT the PD controller TPS2378) negotiates the higher power with the PSE through the data lines. After LLDP negotiation the PSE will turn ON its second port.

  • 0 in reply to Darwin Fernandez
    Mastermind 6180 points

    Hi Darwin,

    Thanks for your help, may I know have TI ever tested TPS2378*2+UCC2897A with CISCO's UPoE switch while UPoE standard released?

    I'd like to convince customer with this, thank you.

    C.T.

  • 0 in reply to chentsu chung
    TI__Mastermind 40700 points

    Hi Chentsu,

    I have not tested with a Cisco UPOE switch particularly; however I know of many projects that use this design in forced UPOE application with no issues. I recommend ordering a TPS2378EVM-602 and testing with a forced UPOE switch to verify any concerns.