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Original question:

TPS65982: TPS65982 Dead Battery, reject non PD device

TPS65982: In TPS65982 Dead Battery mode with BUSPOWERZ = 1.8V, will it negotiate +15V 3A VBUS before closing PP_HV switch?

Reed Wagner
Prodigy 20 points
Part Number: TPS65982

For a board powered from USB-C in dead battery mode, with BUSPOWERZ configured to 1.8V to power the entire system through the PP_HV internal load switch, will it negotiate the power required before it closes the switch and not close the switch if the PD cannot provide the power required? 

In this case the board will run from +15V 3A and will not be capable to run from the initial +5V power available.  The power required needs to be negotiated and the PP_HV switch only be closed after successfully negotiating for the +15V 3A power.  

  • 0
    TI__Expert 4415 points

    Hi Reed,

    Welcome to E2E. 

    Are you using TPS65982 as the sink? If so, the power path will always be PP_HV when you connect BUSPOWRZ to 1.8V. It will load the app code and negotiate the power according to your settings.

    I hope it helps and if it solves your problem, PLEASE select  This resolved my issue  

    Best Regards,

    Hao

  • 0 in reply to Hao Wang14
    TI__Expert 4415 points

    Hi Reed,

    Here is the dead battery condition flow diagram, so in your design, you can set the PP_HV as the input power path in GUI to match your BUSPOWERZ connection.

    Best Regards,

    Hao

  • 0 in reply to Hao Wang14
    Prodigy 20 points

    Hao, Thank you, and also I observed with the TPS65982 EVM that PP_HV goes to 5V for about 700msec before it goes to 15V.  That is good to know for taking measures to prevent the board from trying to power up at 5V, including for the case where someone might plug in an incorrect PD that could not power it at 15V 3A and then it would just stay at 5V.

    While it is operating in dead battery mode, is there a power consumption specification?  Table 6.7 in the TPS65982 data sheet has typicals for Sleep, Idle, and Active but not dead battery.

    Best Regards,

    Reed

  • 0 in reply to Reed Wagner
    TI__Expert 4415 points

    Hi Reed,

    The voltage transition you have tested meets the PD spec. The voltage on VBUS should always goes to 5V when the sink and the source are connected, then the source and the sink negotiate the power, the voltage on VBUS will transient to the new power that they have negotiated. 

    Unfortunately, we do not have the specific power consumption in dead battery mode.

    Best Regards,

    Hao