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TPS92682EVM-070:  Magic smoke on first run with LED load

Part Number: TPS92682EVM-070

Hello,
it seems my brand new EVM died directly after setting the 'Channel 1 Enable' checkbox in the Demo Software. I smelled some magic smoke which came from the TPS92682, I think. After I immediately shut off my power supply, I realized that I activated the Constant Voltage Mode by accident. Please see the attached screenshot, it has been taken directly after this. Can you please confirm, could this be the reason for killing the board?
I think this checkbox has been accidentally activated, because the software crashed just before this. Here on my PC I can let crash the software immediately by moving the 'CH1 PWM Duty' slider by mouse. So I can adjust the PWM Duty only very slowly by the cursor keys.
Currently I read from all chip registers a value of 0xFF so I really think, the chip is dead. However, with the schematic in mind I can't imagine how a suspected wrong register setting could make that happen. Please clarify!

Thanks and Best Regards,
Andreas Lindner

  • Hi Andreas,

    Most likely there is something wrong with the evaluation board now.  Sometimes not having the register programmed correctly can cause failures.

    Thanks Tuan

  • Hi Tuan,

    maybe I should ask the question differently: What will happen if I check or uncheck this 'Constant Voltage' checkbox, at the moment I don't see a relation to any of the chips register?

    Further, I would like to ask, is the source of the software, running on the MSP432 somewhere available? It seems there is only the elf file included within the software installer?


    Thanks,

    Andreas

  • Hi Andreas,

    The 'Constant Voltage' mode changes internal settings and register of the part and how it operates.  This by itself can damage things on the evaluation board.

    As far as the source code on the MPSP432 is concerned, we do not make that available to the public now.

    Thanks Tuan

  • Hi Andreas,

    We believed we have answer your questions and have not heard back from you.  We will close the thread now but will re-open if you reply.

    Thanks Tuan

  • Hi,

    I got a another board and it happened again! I'm pretty sure, it was not my fault. Here is what I did:

    • connected everything but LED load
    • powered the board and did a communication test as written in chapter 8.1 of the user guide
    • proceeded with doing some settings as shown in chapter 8.2
    • GUI crashed while doing so
    • turned off my power supply and connected LED load
    • turned on power supply 
    • started GUI
    • at the moment, when the GUI finished loading, it started some initial communication with the board
    • at the same time, a small flame shot out of the TPS92682 and my power supply went into current limitation (has been set to 5A @ 12V)

    Best Regards,

    Andreas Lindner

  • Hi Andreas,

    We have not experience any of this and we will take this off line.  I will send you a direct email concerning this post.

    Thanks Tuan