• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 62 subscribers
  • Views 366 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

TPS70933EVM-110：TPS70933DBV problem

Ace Chen
Prodigy 30 points
Part Number: TPS70933EVM-110
Other Parts Discussed in Thread: TPS709

Recently, I encountered a problem.
This circuit is applied to the power supply of 12V automobile system.
After using for a period of time, some faults will be found in very few samples:
The output pin of TPS70933 is grounded, causing the car battery to drain.

Whenever I try to analyze the cause of the defect, the defect disappears, as if nothing happened.

Has anyone encountered the same problem?
Who can help solve my doubts?

Regards.

      

  • 0
    TI__Mastermind 23361 points

    Hi Ace, 

    We would need some more details to help with your issue. I saw you probably tried to attach some plots, but it does now show up. You will need to use the insert picture button under the toolbox to upload images to the post. Will you try to re-upload your images?

    Regards, 
    Jason

  • 0 in reply to Jason Song
    Prodigy 30 points

    Hi Jason :

    Thank you!

     I have re-uploaded (Chrome browser cannot open the upload page successfully, so I tried again with IE browser)

  • 0 in reply to Ace Chen
    TI__Mastermind 23361 points

    Hi Ace, 

    Thanks for sharing the schematic, and I don't see any red flag in the design. To further identify the problem, will you help take some scoopshots that show Vin, EN, and OUTPUT? 

    If the LDO is not damaged, it can only be disabled to have an output near the ground level. We would need you to help take those measurements to help us confirm if the LDO is disabled for some reason. 

    Regards, 
    Jason

  • 0 in reply to Jason Song
    Prodigy 30 points

    Hi Jason:

    Will damage to the LDO cause this undesirable phenomenon?
    In addition, if the LDO is damaged, is it possible to return to normal for a short time as I encountered?

    Attach more detailed information:

    TPS70933 supplies power to the downstream GPS and Gsensor.
    The first time I found the problem, I tried to disconnect the power supply of GPS and Gsensor.
    It is found that TPS70933 is still in a short-circuit state (about 2 ohms to ground)

    The appearance of TPS70933 looks good, and I take a X-ray shot for it :

    In addition, when a problem occurs, observe the hot spots through thermal imaging.

    The hot are indeed concentrated on the TPS70933

  • 0 in reply to Ace Chen
    TI__Mastermind 23361 points

    Hi Ace,

    Sorry for the late response. I was on time off and just returned to work today. Based on the X-ray, it does not seem that the TPS709 had been EOSed, and the wire bonds are also intact. 

    To confirm why the TPS709 was causing a short circuit, we would still need to have some test waveforms as I previously requested. Do you think that's something you could get?

    Regards, 
    Jason Song