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TPS25910: Current Limit

Kyle Mehringer
Intellectual 1100 points
Part Number: TPS25910
Other Parts Discussed in Thread: TPS25947, TPS2597, TPS25982, TPS25981

Hello,

We have some questions on TPS25910:

 

  1. What is a safe Rlim value which is smaller than 29.4kohms that we could use?
  2. Is there lowpass filtering on the current limit?
  3. Is this device latching if it trips for any of the limit?

Thank you,

Kyle

  • 0
    TI__Guru 61275 points

    Hi Kyle,

    There is a misprint. RILIM minimum recommended is not zero but 29.4K.

    Choosing RILIM beyond recommended range can give poor accuracy and it is up to the customer to use at that setting and evaluate in their system.

    During current limit power dissipation across device increases due to which it will hit thermal shutdown. After thermal shutdown device will try to rertry.

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    TI__Intellectual 1100 points

    Hello Kunal,

    So it is recommended that a resistor value is at/above 29.4k, and nothing lower? Does the re-try feature you mentioned also apply to other limits (other than thermal)?

    What about lowpass filtering for the current limit?

    Thank you,

    Kyle

  • 0 in reply to Kyle Mehringer
    TI__Guru 61275 points

    Hi Kyle,

    Yes above or equal 29.4K. Device will retry only when it turns off due to thermal shutdown feature.

    I did not understand the motivation behind the question of lowpass filtering on current limit and also the question. Filter is applied on some signal. Current limit is not a signal. Which signal are you interested in?

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    TI__Intellectual 1100 points

    Hello Kunal,

    I received some clarification. By lowpass filtering, they are trying to figure out how fast the device would trip when current limit is exceeded.

    For example: if current limit was exceeded by 0.5A for 10ns and then the current comes back down below the level, would it trip?

    Also, just confirming: this device will latch for all trip except for the thermal trip?

    Thank you,

    Kyle

  • 0 in reply to Kyle Mehringer
    TI__Guru 61275 points

    Hi Kyle,

    During current limit device will not trip it will try to regulate current. That response time should be some 100 of ms . So if current exceeds current limit for 10ns and come back down device will not enter into current limit.

    Also one thing why is customer going with old device? We have new generation devices like TPS25947,TPS25982,TPS2597,TPS25981 that are much cost, performance and space optimized than TPS25910

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    TI__Intellectual 1100 points

    Hello Kunal,

    Is there a specific specification for the response time? Also, just to confirm, this device will latch for all trips except for the thermal trip?

    I will check on if we can move to a newer device.

    Thank you,

    Kyle

  • +1 in reply to Kyle Mehringer
    TI__Guru 61275 points

    Hi Kyle,

    For newer devices we mention response time in datasheet but since this is old device it is not in datasheet.  Yes it will latch other than thermal shutdown event.

    Regards

    Kunal Goel