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TPS65986: DFP power not negotiated properly when far end device disconnected and reconnected

James Price23
Prodigy 80 points
Part Number: TPS65986
Other Parts Discussed in Thread: HD3SS460

I have a design using the TPS65986 as a DFP on my downstream facing port.  My device is constantly powered from a wall wart.  My device has the TPS65986 configured to offer 5V, 9V, 15V and 20V at 3 amps.  

When I plug my design to a far end Type-C device requiring power, everything works great.  The far end device can select any of those voltages, the correct voltage and power shows up on VBUS and everyone is happy.

If I disconnect the Type-C cable from my design and then plug it back in, everything still works great.  All voltages are offered.  Everything works with the connector flipped as well.

Here is the problem:  If I disconnect the far end device Type-C connector and then plug it back in, my design only offers 5 Volts.  The 9V, 15V and 20V are not offered any longer.

If I then unplug the Type-C connector from my device and plug it back in, all voltages are again offered to the far end device.

How do I configure the TPS65986 to re-negotiate power when the far end Type-C is disconnected and then reconnected?

  • 0
    TI__Mastermind 36756 points
    Hi James,

    This could be an issue with the particular cable you are using. Do you have a TPS65986EVM available to duplicate the issue on? Can you also duplicate the issue with various different cables?

    Thank you,
    Eric
  • 0 in reply to Eric Beljaars
    Prodigy 80 points
    I have tried this with 2 different cables, one of them supposedly "certified". I do see slightly different behavior from the 2 different cables, neither correct. I did load the "TPS65986 Downstream-Facing Port Only, supports HD3SS460 Mux" pre-configured project using TPS6598x Application Customization Tool version 3.16. I then modified only the power source info and the gpio configuration so that it matched my hardware. I got the same undesirable results.

    So knowing this, do you think that the problem I am seeing must be on the far end device or be the result of the cables I am using?
  • 0 in reply to James Price23
    TI__Mastermind 36756 points

    Hi James,

    3.16 is quite an old version of the configuration tool. Could you please update to the latest version on TI.com and retest? This would also ensure you are testing using the latest FW version. You would need to create a new project file using the latest tool. However, once you have created your new PJT file, you can import the settings from your old project file by clicking project --> Import settings from project.

    If this answers your question, PLEASE select This resolved my issue

    Thank you,
    Eric

  • 0 in reply to Eric Beljaars
    Prodigy 80 points

    I am running with version 4.03 now but it turns out that was not the problem.

    My end device was misbehaving.  My problem is resolved.