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TPS25946: Revers current limit

Takuya Terada
Prodigy 30 points

Part Number: TPS25946

Tool/software:

Hi TI experts,

I just would like to confirm if my understanding of current limit function is correct.

TPS25946x has current limit function but it only available for positive direction.

Even if ILIM is set to 2A, for example, this device accept like -3A, -4A until thermal protection assert.

Is my understanding correct?

best regards,
Takuya

  • 0
    TI__Expert 7730 points

    Hi Takuya,

    Thank you for your patience

    Yes, your understanding is correct. Current limit function is only available for positive direction.

    Current can flow from output pin to input pin through body diode.

    But body diode cannot handle continuous current.


    Can you provide me details on reason for this query.?

    Best Regards,

    Sailendra

  • 0 in reply to Sailendra Kumar
    Prodigy 30 points

    Hi Sailendra,

    Thank you for your reply.

    Sailendra Kumar said:
    Current can flow from output pin to input pin through body diode.

    I don't understand this.

    I think TPS25946 accept reverse current when it is ON state so current flow into drain-source.

    And if it is OFF state, both FET is off so reverse current never flow.

    Am I wrong?

    Sailendra Kumar said:

    Can you provide me details on reason for this query.?

    In my system, I would like to limit reverse current like -2A, so I asked this.

    And fortunately there is MCU and MCU can turned off when reverse current is higher than the limit.

    best regards,

    Takuya

  • 0 in reply to Takuya Terada
    TI__Expert 7730 points

    Hi Takuya ,

    Thankyou for your patience 


    Takuya Terada said:

    I don't understand this.

    I think TPS25946 accept reverse current when it is ON state so current flow into drain-source.

    And if it is OFF state, both FET is off so reverse current never flow.

    Am I wrong

    You are correct . So during ON state the reverse current flows from out pin to input through body diode of HFET and BFET . The body diode cannot handle continuous higher current . 

    Hope this helps 

    Best Regards ,

    Sailendra