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TPS20xx (TPS2054B in my case) has an overcurrent threshold too high (2x the datasheet spec)

Jeremie Venne
Prodigy 20 points
Other Parts Discussed in Thread: TPS2054B, TPS2052C, TPS2052B

I am using 2 of these usb switch. While testing the output protection, I could not get it to enable its overcurrent protection until applying a 2ohm load to the output. Applying a 2.5ohm load results in a drop of about 200mV on an input of 5V. That drop is not caused by the TPS2054B, but by the LDO powering the TPS2054B because the overcurrent flag was not up.

I need to draw between 1.8A to 2A for the constant current output to be activated !

From the datasheet : "Accurate Current Limit (0.75 A min, 1.25 A max)"

If 2 outputs draw that much current, it will burst the 5V rail before the output protection has even started to limit the current.

Is it normal to be that out-of-spec? Could I be the cause of the problem? 

Thank you in advance for your help

  • 0
    TI__Mastermind 42795 points

    Yes, this older family of power distribution switch has both an Ioc threshold and Ios threshold. the Ioc must be tripped before Ios kicks in and that requires the input source to be able to support Ioc which can be ~2x higher.

    I would recommend using the "C" family of PDS but we don't have a quad part. The TPS2052C is a dual part with very fast short circuit response and flat Ios.

    TPS2052B:

    TPS2052C:

  • 0 in reply to Eric Wright
    Prodigy 20 points

    Thank you very much for your quick reply.

    I had not seen the overcurrent trip threshold parameter.. That explains the behavior.

    Solved! thank you!