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TPS65982: Does internal switch of PP_5V0 turn off when powering off VIN_3V3 under USB device is still attached?

Guru 29720 points
Part Number: TPS65982
Other Parts Discussed in Thread: TPS6598X-CONFIG

Hi Team,

My customer is designing note PC and it is DFP(5V source only) application.
Does internal switch of PP_5V0 turn off when powering off VIN_3V3 under USB device is still attached?

I heard his board shows VBUS is still 5V although turning off VIN_3V3 supply.
Is it possible case for TPS65982?

Please let me know if you need firmware configuration(.pjt file).
Your support would be appreciated.

Best Regards,
Yaita / Japan disty

  • Hello Yaita-san,

    The only way that PP_5V0 can be on when VIN_3V3 is off is if the device is in dead battery mode as a sink.
    Are you sure the device is operating as a source and that VIN_3V3 is disconnected?

    Thank you,
    Eric
  • Hi Eric-san,

    >Are you sure the device is operating as a source and that VIN_3V3 is disconnected?
    Yes, please refer to the following waveform.
    It shows VBUS still supplied from TPS65982(PP_5V0) although powering off VIN_3V3 under Firmware version 1.11.9 (from TPS6598X-CONFIG ver 2.12.1 )
    My customer also found LDO_3V3 still outputs 3.3V after powering off VIN_3V3.


    note: system power (include PP_5V0) is off 10 second later from shutdown in his system.

    On the other hand, my customer evaluated same test with same firmware configuration under Firmware version 1.11.5 (from TPS6598X-CONFIG ver 2.10).
    It shows differnt result as the following.
    VBUS (and LDO_3V3) decreased to 0V after powering off VIN_3V3 in this case.


    I believe latter result is normal feature and concern there is bug in Firmware version 1.11.9 (TPS6598X-CONFIG ver 2.12.1 ).

    Could you confirm this issue in TI?
    Your quick support would be really appreciated because of my customer's design schedule.

    If you needs additional information or has something unclear, please let me know.
    yaita-k@clv.macnica.co.jp

    Best Regards,
    Yaita

  • Hello Yaita-san,

    We are currently looking into a fix that may have caused this issue.
    In the mean time, is there anything in your system that is being harmed by this? Please let me know.

    Thank you,
    Eric
  • Eric-san,

    I appreciate for  focusing on the issue.

    >In the mean time, is there anything in your system that is being harmed by this? Please let me know.
    My customer already used TPS65982 in previous released model and it is problem because there is difference feature with current designing model using Firmware version 1.11.9.
    In addition, USB device loads some current even if the system (note PC) is shutdown.

    He considers to adopt Firmware version 1.11.5 (previous version) because of the issue.
    Do you recommend to use version 1.11.5 at the moment?
    Is there any version between 1.11.5 and 1.11.9?
    I would also like to know when do TI plan to fix the issue of Firmware version 1.11.9.

    Best Regards,
    Yaita / Japan disty

  • Yaita-san,

    We have logged the issue for the next release of the Firmware. We currently do not have a schedule for it's release.

    Thank you,
    Eric
  • Eric-san,

    Thank you for your reply. I undedrstood TI doesn't have a schedule now.
    How does TI think the following?
    >Do you recommend to use version 1.11.5 at the moment?
    >Is there any version between 1.11.5 and 1.11.9?

    Best Regards,
    Yaita