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TPS23754: The protection process of over current condition and shorted circuit

chentsu chung
Mastermind 6180 points
Part Number: TPS23754

Hi,

I'd like to know what's the OCP or SCP in TPS23754?

1. While such condition happened, is the PSE limit the current and cut off first or TPS23754 will protect itself first?

2. What's the TI's PSE protection process?

3. What's TPS23754's OCP and SCP process?

Thank you very much.

  • 0
    TI__Mastermind 40100 points
    Hi Chentsu,

    1. Typically, the PSE's current limit is lower than the PD's current so first line of protection is the PSE. This way, if there is fault on the PD side, the PSE will be able to catch it and be able to react rather than the PD cycling on the fault condition and PSE stays connected.

    2. We've seen PSEs that can have a hard current limit and we've seen PSE's that foldback.

    3. There will be some cases where the PD will protect itself before the PD (like if PSE does not react fast enough during a hotshort). The PD will reach it's current limit 850mA and then foldback (VDD-RTN) will drop. If the fault still occurs, the PD will go into inrush current limit (140mA).

    Note that the above description describes the PD controller functionality of the TPS23754. At a system level design with the DCDC converter, it will also have its own protection (current mode controlled) during a DCDC output fault.
  • 0 in reply to Darwin Fernandez
    Mastermind 6180 points

    Hi Darwin,

    Thanks for your responce.

    So, for the PD side protection, it should foldback protection whild current reach the 850mA limitation.

    But from the shorted circuit test, it seems keep running if shorted circuit doesn't remove.

    The testing waveform:

    Or TPS23754 will turn off while VC goes low dut to bias winding can't support enough energy? But this is not current foldback protection, am I right?

  • 0 in reply to chentsu chung
    TI__Genius 9230 points
    Hi Chentsu,

    It appears your question was answered here: e2e.ti.com/.../707276
    And here: e2e.ti.com/.../705507

    Thanks,
    Tom