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TPS25751: 20V without PD negotiation

Victor Hansen
Prodigy 30 points
Part Number: TPS25751

Tool/software:

Hello TI Forum.

I have a rather special request concerning the TPS25751D. Is it possible to edit the firmware so that it allows 20V without a PD negotiation?
I know that from the USB standard, this is not so as anything beyond 5V requires a PD negotiation. The reason why I need this is because I have to power a USB-C application from a DC lab power supply that uses banana plugs. I can cut open a USB-C wire and extract the power lines from this, but then I will not have any PD negotiation.

I can of course use the USB-C PD Duo EVM (SLVUBJ5) to obtain the desired effect, but I am worried how much the impact of the Duo board will have on my EMC measurements.

Therefore, is it possible in any way to "disable" the PD negotiation in firmware so that the PD controller will allow 20V straight through?

Thanks in advance.

Kind regards,
Victor

  • 0
    TI__Mastermind 37855 points

    Hi Victor,

    No, there is no way to utilize the TPS25751 power path and pass 20-V through without PD negotiation. The firmware has checks in place for correct voltages and negotiation before closing the power path. As you mentioned, this is not compliant with the USB standard and defeats the purpose of USB-PD (safe negotiation of high voltages).

    You would need to use a separate power switch directly in your control to achieve such behavior.

    Thanks and Regards,

    Chris