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TPS2557: Backfeed Protection

Benjamin Haag
Prodigy 20 points
Part Number: TPS2557

Tool/software:

We have a TPS2557 down in a design now for a USB host port. Our concern is if a user connects the USB host port to the host port of another device while our device is powered down, thus backfeeding our VBUS line. The block diagram for the TPS2557 device operation implies the input and output are isolated by a MOSFET, however does this device truly prevent backfeeding from the OUT pin to the IN pin?

  • 0
    TI__Mastermind 27530 points

    Benjamin,

    The TPS2557 will prevent any current flow from IN to OUT, but it is a single FET power switch, so it does have the body diode that will conduct current from OUT to IN.

    If you need isolation from OUT to IN, then you will need to find a 2 FET power switch that offers reverse current protection.  I did a quick search on our power switches and I did not find one that meets your needs.

    Regards,

    Chuck