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TPS65982 (UFP) - Possible to configure to pass 12V source (DC barrel jack)?

Jonathan Bender
Expert 7895 points
Other Parts Discussed in Thread: TPS65982, TPS65982-EVM

Hello,

For TPS65982 in UFP role, is it possible to pass a non-PD source (12V DC barrel jack), either through the internal power path (PP_HV) or the external FET (PP_EXT)?

On the TPS65982-EVM, "Configuration ID 3: Notebook (or Mobile Workstation) That can Pass AC-Adapted Power" seems to describe this use case, but I'm not sure if I'm understanding it correctly. If there's no PD DFP, will ID 3 pass the barrel jack 12V to VBUS?

Thanks,

Jonathan

  • 0
    TI__Mastermind 30310 points

    Jonathan,

    Let me clarify here:

    Are you saying you want to pass 12V from a Barrel Jack from PP_HV (or PP_EXT) to VBUS as a Power Source?

    If so, then yes! This is easy and we do it all the time. The TPS65982 converts the 12-V Barrel Jack to become a PD source through the policy engine and PD negotiation.

    In order for a UFP to become the Power Source, it will need to be enabled as a Dual-Role Port.

    The TPS65982 will most likely become the DFP/Source first and negotiate a Data Role Swap to become the UFP.

    There is always a DFP according to the PD spec, even if neither side wants to transmit data.

  • 0 in reply to Brian Berner
    TI__Expert 7895 points

    Hi Brian,

    Thanks for the quick reply. I may have worded it poorly, so hopefully this block is more clear:

    I want TPS65982 to sink the 12V from the barrel jack, to supply to the system.

    Sometimes I'll have a proper USB Type C DFP-enabled charger instead of the 12V barrel jack, so in those cases it will negotiate with TPS65982. But I'd like to be able to pass this DC barrel jack power if a Type C charger is not available.


    Let me know if this is still an acceptable use case,

    EDIT: I had flipped PP_HV and VBUS in my original block, so I fixed it w.r.t. the proper direction for the sink case.

    Thanks,

    Jonathan

  • 0 in reply to Jonathan Bender
    TI__Expert 3625 points

    Hi Jonathan,

    As Brian stated in his previous post this is a standard use case that the TPS65982 supports and handles via its internal PD Policy Manager and PD negotiation. You can see this functionality already in the TI USB-C Reference Design TIDA-00630.

    Regards,

    Karl

  • 0 in reply to Karl Fleischmann
    TI__Expert 7895 points

    Hi Karl,


    Thanks for the reply. I think I see where the confusion lies now, after going through the TIDA-00630 schematic.

    On TIDA-00630, the DC barrel jack provides power directly to three DC/DCs, one of which (12Vout) is tied directly to the HV_Source net (PP_HV), completely bypassing TPS65982.


    In my use case, I wanted the DC barrel jack to be connected to the VBUS net, and for TPS65982 to let it pass through the internal power path, enjoying the current limiting and other features a PD-negotiated source would have.

    However, in the dead battery case, 5V and 3.3V would need to be generated by the external power source via DC/DCs, which adds complication, size, and cost. In the end, I think implementing something closer to the TIDA-00630 topology is the best solution, even though I don't need source capabilities.

    Let me know if what I said above makes sense and you agree with my analysis / conclusion.

    Thanks,

    Jonathan

  • 0 in reply to Jonathan Bender
    TI__Expert 7895 points

    Just wanted to close this thread off - after discussing offline, the DC barrel jack cannot be applied directly to VBUS, as this is a violation of the USB spec. To have a HV source passed through VBUS, it must be negotiated by a proper DFP first.

    Thanks,

    Jonathan