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TPS2595: About setting the current limit

Kaji@PAN
Mastermind 7775 points
Part Number: TPS2595
Other Parts Discussed in Thread: TPS25947

Hello,

I previously asked about setting I_LIM in the following thread.
In that regard, I would like to ask you a question.

(Question 1)
I am considering setting an I_LIM that exceeds the recommended value of 4A.
However, I plan to set it within the range of 5A, which is the guaranteed design value.
The RILM variability used is ± 1%.
As a reference value, the current limiting accuracy is ± 7.5%.
Considering the above variations, select R_LIM = 440Ω, which maximizes the current limit range as much as possible.
In the calculation, I_LIM (MAX) = 4.98A should be the value considering the variation.

Is it okay to use R_LIM = 440Ω?
Is 440Ω set within the design guarantee?

(Question 2)
In 7.3 Recommended Operating Conditions, C dV / dt is stated as MIN = 3300pF.
Is there a MAX value?

Please let me know any other restrictions or precautions when using this device.

Best regards,

e2e.ti.com/.../tps2595-setting-i_lim-between-4a-and-5a-and-the-resistance-value-in-that-case

  • 0
    TI__Guru* 79071 points

    Hi Kaji,

    1. ± 7.5%. accuracy is only for current limit 0.5 A to 4A and is tested by us. But if you set current limit above 4A then that is not tested by us and we can not guarantee accuracy.

    2. My advise is that if you choose RILIM=440ohm please test accuracy on your system.

    3. As I said before 5A current limit is just a design concept and we do not have test data for this . 

    4. You can choose another device TPS25947. It has current limit upto 6A tested.

    5. Yes there is no restriction on max cdvdt cap value. How much you want to keep?

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    Mastermind 7775 points

    Thank you for your reply.
    I understand that the 5A setting is a design guarantee and has not been tested for variability.
    Change the way you ask questions.
    In the calculation of RILM, when calculated at 5A, RILM becomes 403Ω.
    If the resistance value is 403Ω or more, is it a guaranteed design value?
    I would like your opinion as to whether the resistance value itself to be set is possible.

    Best regards,

  • 0 in reply to Kaji@PAN
    TI__Guru* 79071 points

    Hi Kaji,

    I will get back to you at earliest.

    Regards

    Kunal Goel

  • +1 in reply to Kunal Goel
    TI__Guru* 79071 points

    Hi Kaji,

    I cannot say for sure. You can try using the formula and set value as 5A and later tune the resistor based on testing in lab. You can order EVM of this device and test on it.

    Regards

    Kunal Goel