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TPS274160: Questions regarding the "fast-trip" feature

Darren (FAE)
Expert 5483 points
Part Number: TPS274160

I have some questions regarding the fast-trip function (refer to top of P18 in the DS)
These questions don't have answers in the datasheet, but are important for understanding system operation.

I understand that an "Enable-into-Short" = "Enable-into-Capacitive-Load" and both situations will limit the current to the set threshold after a small overshoot.
I understand the "fast-trip" only happens after the channel has already been enabled, and a sudden current spike (hot-short-to-GND) occurs.

1) How long after the channel is enabled before "fast-trip" is active? (there has to be some propagation delay)
2) What is the current spike? (i.e. 1.6x the set current limit)
3) The datasheet says the response-time is <1[us] (typically) - but what is the worst-case response time? 5[us]? 10[ms]?
4) The datasheet says the "channel is disabled" after the fast-trip. But what happens next?
Does the channel auto-retry? If it does, how long from getting shut-off before it tries to start-up again?
If there is auto-retry, then I assume on re-try it would revert to current-limiting/thermal-shutdown, instead of shutting down the channel, right?

Regards,
Darren

  • 0
    TI__Genius 16390 points

    Hi Darren,

    Thanks for reaching out. As these questions are specific to the internal design, we will check with the design team and get back to you. As people are taking holidays now, there might be a delay in the responses.

    Thanks!

    Regards,

    Yichi

  • +1 in reply to Yichi Zhang.
    TI__Genius 16390 points

    Hi Darren,

    We got some feedback from the design.

    In general, we don't have the test bench for this older part, and the below are estimations.

    1) The time is estimated to be a couple us.

    2) The peak should be max at 2.7x like our new part (typical will be less). Again, this is just an estimation and we don't have a verification.

    3) The worst case would be under 10us. But it would be very close to the typical value 1us most of cases.

    4) It will retry to current limit and then eventually hit thermal shutdown. Again, it would be the best for the customer to test on an EVM and verify.

    Please let me know if you have additional questions.

    Regards,

    Yichi