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TPS65982: Powering PP_EXT without 3.3Vin

Andrew Park1
Prodigy 460 points
Part Number: TPS65982

Team, 

my customer is using TPS65982 on monitor system and here is an issue they asked me. 

normally the system acts as a power source provides 20V out to connected devices using PP_EXT.(the input for PP_EXT is coming from the barrel jack).

the issue is that this monitor keeps charging connected device with 20V even when they turn off the system. 

once they turn off the system by asserting low to VIN_3V3, VDDIO and PP_5V0, they have been expecting charging would be stopped. 

the PD controller is gate driving when there is no power on 3.3V and 5V input. of course there is no more charging after unplug the cable and plug again. 

can you check this and explain why this happens?

  • 0
    TI__Mastermind 36751 points
    Hi Andrew,

    May I know which FW version your customer is using? We had a fix for this issue with FW Version 1.12.00 on the TPS65982. Using the updated FW should resolve the customer issue.

    Thank you,
    Eric
  • 0 in reply to Eric Beljaars
    TI__Prodigy 460 points

    Eric, 

    the issue has been resolved by your suggestion. however we are seeing a different issues regarding 3.3Vin.

    Here are two unexpected behavior with TPS65982.
     

    1.       1. When system VIN_3V3 has removed from Monitor(sourcing 20V to PC(MAC)), It receives power(5V) from Mac. Even we tied RPD_G1&2 to GND to disable dead battery boot up.

     
     can you check this and guide how we can disable power sinking(5V) from Mac and how we can make re-negotiate to provide 20V to Mac?
    Thanks,
    Andrew

    2.       2. When we enabled VIN_3V3 again, the power doesn’t negotiate again so that the system(Monitor) can’t provide 20V power to Mac again.

     
    Here are two unexpected behavior with TPS65982.
     

    1.       When system VIN_3V3 has removed from Monitor(sourcing 19V to PC(MAC)), It receives power(5V) from Mac. Even we tied RPD_G1&2 to GND to disable dead battery boot up.

     
     

    When we enabled VIN_3V3 again, the 

  • 0 in reply to Andrew Park1
    TI__Mastermind 36751 points
    Hi Andrew,

    I believe these issues are due to the configuration on the TPS65982. You can edit the configuration using the Application Customization tool. To resolve issue #1:
    In the TPS65982 Application Customization Tool, edit the Control Configuration and confirm that "Process Swap to Sink" and "Initiate Swap to Sink" are both disabled. Then, under Transmit Sink Capabilities, set the number of Sink PDOs to 0. This will ensure that the TPS65982 is never sinking power from the PC.

    To resolve issue #2:
    In the TPS65982 Application Customization Tool, in the Control Configuration, make sure that "Initiate Swap to Source" and "Process Swap to Source" are both enabled. Also, ensure that under Transmit Source Capabilities, the 20V PDO Advertise Mask is set to Always Advertise.

    Thank you,
    Eric
  • 0 in reply to Eric Beljaars
    TI__Mastermind 36751 points
    Hi Andrew,

    Did my recommendation above help resolve your issue?

    Thank you,
    Eric