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TPS23750EVM-107： TPS23750EVM

user5338063
Prodigy 20 points
Part Number: TPS23750EVM-107
Other Parts Discussed in Thread: TPS23750

Hi,

I recently purchased a development board, but when I found out that it did not work properly, the specific performance is that the OUTPUT port has 5V voltage discontinuity.

Below is the output waveform I tested and the HSE switch I used. TL-SG1218P

Can anyone answer me or solve this problem?

Regards,

Ender

  • 0
    TI__Mastermind 21320 points

    Hello Ender,

    I have a TPS23750EVM-107, and i just tested it in the lab and it regulated at 5V no drops. Did you make any modifications to the board?

    Can you confirm your oscilloscope window is 1 second per division on the time scale and 1V per division on the vertical scale?

    If that is the case, then the voltage is dropping once every two seconds from 2.5V to 1V. If it is 2 volts/div, then it is up to 5V and dropping to 2.5V. I want to understand what is happening in the system. 

    Additionally, can you test the input voltage on TP12, and the gate voltage? 

    Finally, I am curious to know what end equipment you (or your end customer) is designing?  Might I know your company name and/or end equipment?

    Thank you!

    Regards,

    Michael Pahl

  • 0 in reply to Michael Pahl
    Prodigy 20 points

    Hi Michael Pahl,

    I am very sorry, the TPS23750 EVM was burned down due to my mistakes yesterday. But there is a TPS23753AEVM around me, and their phenomenon is the same.

    Below is the output waveform of the TPS23753AEVM and the GATE waveform.

    Due to the equipment, I can't directly measure the input voltage waveform, but I can measure it to reach 48V and then fall off with a multimeter.

    Finally, I have not modified these two boards. When I bought them, I tested and found this problem.

    Thank you!

    Regards,

    Ender

  • 0 in reply to user5338063
    TI__Mastermind 21320 points

    Hello Ender,

    Thank you for providing those waveforms for me.

    The second Vout was very insightful. As you can see, the board regulates a voltage for 300ms, and then there is a slow discharge. What is happening is this specific EVM is considered to be a very light load. So light, that it does not draw enough power for the MPS to work with the PSE. If you do not connect a load to the board, this can happen when powered by a PSE.

    So to fix it you will need at least a 50 ohm load. I took the EVM I tested last week and reproduced this exact issue. I can also confirm it was fixed when I attached a 50 Ohm load.

    Please give this a try or power the board with a DC power supplies. Please let me know how your test goes! 

    Regards,

    Michael Pahl

  • 0 in reply to Michael Pahl
    TI__Mastermind 21320 points

    Hello Ender, 

    Have you had the chance to try a 50 ohm load? I want to make sure we confirm this is the solution or that we continue to troubleshoot the issue. 

    If this does make the board regulate, please mark this thread closed. If not, please let me know and we can continue to work on this together.

    Regards,

    Michael Pahl

  • 0 in reply to Michael Pahl
    TI__Mastermind 21320 points

    Hello Ender,

    I wanted to check in on you with this question. I want to make sure you are setup for success with your project. 

    If I do not hear from you in a few days I will assume your question is answered and I will close this thread. Please let me know your progress and we can continue from there. Thank you!

    Regards,

    Michael Pahl