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TPS25200: Dynamic current limit with changing external RILIM

Luke Sakamoto
Intellectual 2905 points

Part Number: TPS25200

Hi team,

May I know if this IC supports dynamic current limit?

Customer would like to change the external RILIM value while EN=High. Below points are important to the operation of this end equipment.

  • RLIM decrease while EN=High to increase the current limit.
  • RLIM increase while EN=High to decrease the current limit.
  • While current limit value changes, there should be no hiccup/retry of the power switch. Continuous sourcing of the voltage is needed.

I see below E2E posts but did not see clear answers.

 

Thanks,

Luke

  • 0
    TI__Genius 11870 points

    HI luke 

    Can I get the current limits needed to be present before and after EN is high . But one questions , when the EN=low, the device will be already disabled so what do you mean by having a current limit when the device itself turned OFF. 

    Do you mean at the time of inrush and after inrush ?
    Best Regards,

    Sailendra

  • 0 in reply to Sailendra Kumar
    TI__Intellectual 2905 points

    Hi Sailendra,

    Sailendra Kumar said:
    Do you mean at the time of inrush and after inrush ?

    Yes. During inrush, we want to lower the current limit and after inrush, we want to increase (release) the current limit.

    It will follow below procedure:

     - Vin=H, EN=H, Current limit = lower current.(high RILIM)

     - inrush

     - Current limit = higher current. (low RILIM via transistor switch)

    Also, there may be a need to do the opposite operation, higher current -> lower current.

    Thanks,

    Luke

  • 0 in reply to Luke Sakamoto
    TI__Genius 11870 points

    Hi Luke,



    You can connect this way so that , ILIM changes as required. Can I know if you will be giving any control signal for ILIM to change or it should happen automatically

    Best Regards,

    Sailendra

  • 0 in reply to Sailendra Kumar
    TI__Intellectual 2905 points

    Hi Sailendra,

    Thank you for your quick reply.

    Sailendra Kumar said:
    Can I know if you will be giving any control signal for ILIM to change or it should happen automatically

    There will be signal (logic) coming from the system to indicate inrush has finished. That signal will be toggling the above diagram's FET Gate to change the ILIM value.

    Just to confirm:

    This transition will be smooth (no hiccup), right?

    The transition can go both ways, ILIM FET Gate can go L->H and H->L, right?

    Thanks,

    Luke

  • 0 in reply to Luke Sakamoto
    TI__Genius 11870 points

    Hi Luke

    Luke Sakamoto said:

    This transition will be smooth (no hiccup), right?

    There will be no hiccup , since inrush is already done.

    Luke Sakamoto said:

    The transition can go both ways, ILIM FET Gate can go L->H and H->L, right?

    Yes, basically it depends on how you use the control signal , if it gives the gate of external FET high when inrush is done , then RLIM goes high to low , if it gives low signal when inrush is done , then the RLIM goes low to high

    Best regards,

    Sailendra