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TPS65987D: Power up without VIN_3V3

Gim Song
Intellectual 1120 points
Part Number: TPS65987D

Hi,

In this project, TPS65987DDJ is used as DEVICE (with no other external power and battery) where the power is coming from USB Type C VBUS connected. Based on the datasheet section 8.3.2, it mentioned that, when VIN_3V3 is unavailable and VBUS/VBUS2, TPS65987D can be powered up.

Questions:

1) In this case, do we still need to supply VIN_3V3?

2) If question 1 is yes, is there a timing requirement when VIN_3V3 must be available after VBUS is plug in?

Thanks.

Gim Song

  • 0
    TI__Mastermind 30000 points

    Hello Gim,

    Not having powered supplied via VIN_3V3, and have the device powered from VBUS is what we call a "dead battery" condition. In this case, no you do not need to supply power to VIN_3V3 as the core architecture will be powered from VBUS. You can read section 8.3.5 within the datasheet.

  • 0 in reply to Adam Mc Gaffin
    TI__Intellectual 1120 points

    Hi Adam,

    Appreciate for your feedback.

    We will still supply VIN_3V3 (from DCDC) after getting supply from VBUS to make the system stable in case VBUS may disappear/drop as power role swap will be perform if there is an external adapter plug into the system.

    Thanks.

    Gim Song