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TPS6594EVM: No buck output

Adam Mielewczyk
Prodigy 90 points
Part Number: TPS6594EVM


Hi,
I'm encountering an issue with the TPS65941111EVM. The only physical action I've taken is connecting VSYS. When attempting to enable any buck output via quick-start with VSYS connected to 3.3V using the stock NVM, I don't observe any voltage. However, when I use 5V, there is no such issue. The LDO output always works fine.

Buck output also worked fine when I conducted another test where I started with VSYS at 3.8V and then gradually reduced the voltage to 3.3V before attempting to turn on the buck output.
However, when I reversed the process, starting at 3.3V and then increasing to 3.8V, the issue persisted.

I'm uncertain if this behavior is normal. What's particularly concerning is the SPMI_ERR_INT, which only occurs when VSYS is lower than 3.8V."

  • +1
    TI__Mastermind 20619 points

    Hello Adam,

    I have been trying to help out in the other thread, the one with connectivity issues.

    As it stands the TPS65941111EVM comes with the TPS65941111 on the board which is suppose to be used with with another PMIC outlined in the User's guide below.

    See here for the part usage: CLICK HERE FOR PDN-0C USER'S GUIDE

    This PMIC will not function on it's own since there is no master PMIC (TPS65941213).

    Can you confirm the first three registers of the PMIC?

    Or have you reprogrammed (flashed) the device on the EVM since receiving it?

    Thank you,

    Nicholas

  • 0 in reply to Nicholas McNamara
    Prodigy 90 points

    I haven't reprogrammed the device before your answer. I wanted to confirm that the EVM is working correctly before any flashing, to rule out a faulty board before further evaluation.
    I wasn't expecting that changing VSYS to a value still in the recommended range would change the behavior.
    I also assumed that EVM was configured as master because it came selected as master on the J37 header.

    So now I reprogrammed the device with my simple configuration (with only one PMIC) after making sure I can restore NVM to stock.
    Now I have voltage on the buck output on VSYS connected to V3V3.
    Thank you for your help Grinning

  • 0 in reply to Adam Mielewczyk
    TI__Mastermind 20619 points

    Hello Adam,

    That's wonderful! I'm very glad to hear that you're able to start up the PMIC and get the outputs you were expecting.

    Yeah, the VSYS voltage is what dictates the control of the safety FET. Possibly signaling an over voltage event.

    Adam Mielewczyk said:
    I also assumed that EVM was configured as master because it came selected as master on the J37 header.

    I see, myself I would expect the same as even the guide tells us about it's usage.

    Either way, if you have any other questions regarding programming or anything else regarding the PMIC, be sure to start another thread so we can focus on that question! Smiley