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TPS272C45: Latch off mode, FLT latch

Miroslav Mrdjan
Prodigy 175 points
Part Number: TPS272C45

Hello,

We are struggle to understand datasheet regarding Latch-off mode when LATCH pin is high.

From picture, a thermal shutdown appears and FLT is reset by simple toggling of EN pin.
However, in the datasheet is written like this


So as we are not changing polarity of LATCH pin (remains High) how the FLT indication disappear?

Best regards,
Miroslav

  • 0
    TI__Genius 16075 points

    Hi Miroslav, 

    Could you probe the LATCH pin to confirm voltage is greater than 2V?

    Could you also zoom into the secondary FLT assertion to see if output current is being drawn at a finer time scale? 

    Best Regards, 

    Elizabeth 

  • 0 in reply to Elizabeth Higgins
    Prodigy 175 points

    Hello Elizabeth,

    Thanx for reaching me out.

    LATCH pin is greater than 2V.
    Just to be sure we are on a same track I'll clarify question:
    Does EN toggling in either latch or auto-retry mode also toggles FLT pin?

    Example:
    1. Lacth mode is ON (LATCH pin High)
    2. We have a FLT indication due to overcurrent. (FLT pin Low)
    3. If EN is back to low will FLT also follow and return to High?

    Best regards,
    Miroslav 

  • 0 in reply to Miroslav Mrdjan
    TI__Genius 16075 points

    Hi Miroslav, 

    Thank you for the clarification. 

    I understand your question now, however unfortunately we do not have any evaluation modules on hand. 

    I am waiting for design confirmation, or the EVM to be delivered. 

    I will provide an update by Monday. 

    Best Regards, 

    Elizabeth 

  • +1 in reply to Elizabeth Higgins
    TI__Genius 16075 points

    Hi Miroslav, 

    I just received confirmation, the FLT will go high as soon as EN goes low when LATCH is high. 

    This is how we determine which channel is faulted when using version A of the device which has a single FLT pin. 

    Best Regards, 

    Elizabeth 

  • 0 in reply to Elizabeth Higgins
    Prodigy 175 points

    Thanx Elizabeth,

    one last question. Is that aligned with the datasheet description?

    Best regards,
    Miroslav

  • 0 in reply to Miroslav Mrdjan
    TI__Genius 16075 points

    Hi Miroslav, 

    I think the confusion here is the statement below: 

    This statement is true when you consider the fault indication and switch turning back on as an ANDed result of the listed conditions (the fault indication is reset AND the switch turns back on) which I believe was the intention. 

    However it is true the fault indication will be reset and the switch not turn back on under other conditions. 

    We will work to make this more clear in the datasheet. 

    Best Regards, 

    Elizabeth