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TPS25924: Hysteresis of Current limit

Shuji Ishiwata
Mastermind 7755 points
Part Number: TPS25924

Hi All,


I have a question about TPS25924.

IFIASTRIP has hysteresis, but the value of hysteresis is not known in Fig37.
What is the value of hysteresis?

Also, are there hysteresis in the IOL and ISC? If so, please tell me the value of hysteresis.


Best Regards,
Ishiwata

  • 0
    TI__Guru* 79071 points

    Thanks for reaching out!

    What does hysteresis imply? Do you mean min and max values?

    Please see the circled values these are min, typical and max values.

    Regards

    Kunal Goel

    ------------------------------------------------------------------------------------------------------------------------------

    Please click "This resolved my issue" button if this post answers your question.

  • 0 in reply to Kunal Goel
    Mastermind 7755 points

    Thank you for your reply.

    I have determined that there is hysteresis in the block diagram below.

    What I want to know is the current value that is released after detecting the Current limit.
    That's why I heard hysteresis.


    Best Regards,
    Ishiwata

  • 0 in reply to Shuji Ishiwata
    TI__Guru* 79071 points

    Hi Ishiwata,

    Hope you are doing well!

    The hysteresis value of fast trip comparator is a  internal IC design spec and is a TI IP .  But the device functioning takes care of this hysteresis. TPS25924x incorporates a fast-trip comparator, which shuts down the pass device very quickly when IOUT > IFASTRIP, and terminates the rapid short-circuit peak current. So as output current falls to zero  and is well below the release threshold of fast trip comparator.

    Regards 

    Kunal Goel 

    ------------------------------------------------------------------------------------------------------------------------------

    Please click "This resolved my issue" button if this post answers your question.

  • 0 in reply to Kunal Goel
    Mastermind 7755 points

    Hi Kunal,

    Thank you for your reply.

    Are there hysteresis in the IOL and ISC?
    Will IOL and ISC retry by detecting the current?
    I would like to know how to retry IOL and ISC.

    Best Regards,
    Ishiwata

  • 0 in reply to Shuji Ishiwata
    TI__Guru* 79071 points

    Hi Ishiwata,

    May I know the reason for asking about hysteresis? Please do not worry about it.

    Please see :

    When the output current is greater than IOL the comparator senses it and sends a signal to gate control block. The gate control block adjusts the current through device to be IOL. If during overload the current falls below IOL then the device quickly exits the current limit mode.

    When current through device is set to IOL ,output voltage falls and total power dissipation ,(VIN-VOUT) *IOUT across device increases. This causes an increase in device temperature and when device temperature reaches thermal shutdown threshold it shuts down.

    After thermal shutdown:

    In TPS259240, latched version  the output remains disconnected (MOSFET open) until power to device is recycled or EN/UVLO is toggled (pulled low and then high).

    In TPS259241,auto retry version device remains off during a cooling period until device temperature falls below TSHDN – 10°C, after which it attempts to restart. This ON and OFF cycle continues until fault is cleared. 

    Regards

    Kunal Goel