This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS23881: Non-PoE Protocol Consult

Part Number: TPS23881

Hi Team,

Customer is consulting whether our TPS23881 can support forced power supply to directly output 54V, that is, it does not follow the POE protocol (detection classification)? If yes, does it still can achieve current detection, overcurrent protection function in the meantime?

Best,

Stanley

  • Hi Stanley,

    You can set the port in manual mode and use 0x19 to force the power on ports. Thanks.

    Best regards,

    Penny

  • Hi Penny,

    Thanks for helps. I checked the D/S, it seems any detection or classification are disabled in the manual mode. So how about the overcurrent protection functions? Does this still achievable? 

    Best,

    Stanley

  • Hi Stanley,

    Yes. Overcurrent protection is still available in manual mode. Thanks. 

    Best regards,

    Penyy

  • Hi Penny,

    In summary, customer still has concerns about the manual mode. Because our D/S indicates this mode is only for the diagnostic purpose. Pls double check again below customer demands can be achieved or not by our TPS23881. I also will reach to u if a webex call is needed between customer and BU.

    Customer system demands:

    1. Supply power directly without using the POE protocol,

    2. Have voltage/current monitoring (the specific value can be read through I2C interface),

    3. Overcurrent protection function (automatic shutdown during overcurrent/short circuit) is needed,

    4. 2-port, power around 50W is needed.

    Best,

    Stanley

  • Hi Stanley,

    Yes. Manual mode can be used for their nonstandard application.  This is considered as "ports cannot be powered up in accordance with IEEE802.3bt standard from semiauto or auto modes". 

    Voltage/current monitoring and overcurrent protection are all available in manual mode. They can order TPS23881EVM to do some testing for evaluation. Thanks. 

    Best regards,

    Penny

  • Hi Penny,

    I want to add some questions here from customer. Pls feel free reach to me by e-mail if needed. Thanks

    1. In manual mode, for 2-pairs application our TPS23881 can achieve 65W in maximum shown in below D/S, right? Or we should leave some margin here?

    2. In Manual mode, how to detect whether is there PD device plugged in? Customer needs to know so they can send power enable command.

    3. For power policing functions, why 0x1E register s becoming to all "F" value (equal to "127.5W") when triggering over-load protection? 

    Best,

    Stanley

  • Hi Stanley,

    1. The 2pair PCUT tolerance is shown on datasheet. 

    2.You still can enable detection and classification to tell if there is a PD connected or not.

    3.When port is not powered on the default value is 0xFF.

    Best regards,

    Penny

  • Hi Penny,

    Currently customer is working our TPS23881EVM but they cannot output ~60W power by using our GUI in manual mode. Could you pls show us how to do it here? Thanks.

    Best,

    Stanley

  • Hi Stanley,

    You should set the power allocation in register 0x29 to 90W. After you connect a PD to the 4pair port and turn on the port, check with 2pair and 4pair PCUT values are correctly set.  

    In your case, what kind of fault is reported on the port when you increase the power to 60W? Can you provide more details about your test setup and GUI configurations?  Thanks.

    Best regards,

    Penny

  • Hi Penny,

    After following your recommendations, customer still cannot get 60W power output. Pls see below our GUI screenshot. Thanks.

    Best,

    Stanley

  • Stanley,

    I am able to run ~60W on the manual mode port. What's kind of device is connected to the port? 

  • Hi Penny,

    Thanks for help. After debugging, TPS23881 can output 65W power after turn on "2x foldback selection" and turn off "DC Disconnect". Do you know what's the reason about it? Thanks.

    Best,

    Stanley

  • Staley, 

    For >15w PD, 2X is needed to increase the ILIM. I am not sure why DC disconnect needs to be disabled. Maybe your PD doesn’t provide valid MPS current. 

  • Hi Penny,

    Thanks for helps here. Another demand from customer is that they want our TPS23881 can automatically recover when overload or circuit short happens. Do you have any system solution for solving this here? 

    Another questions is when overload or circuit short happens, which register will set in our controller?

    Best,

    Stanley

  • Hi Stanley,

    If you configure the device to manual mode, the device will not turn on automatically after overload. The host needs to re-enable the port. When the overload happens the fault event registers will get set. Thanks.