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Original question:

TPS2595: Current limit below 0.5A

TPS2595: TPS259540 / Rilm = 5kOhm allowed or not?

Hans
Genius 12705 points
Part Number: TPS2595

Hello Team,

according to data sheet page 7 a max Rilm of 5kOhm is allowed. If I use the formula (4) on page 21 with 5000Ohm I get a current limit of 0.44A which is below the specified 0.5A on the first page.

Question: is the formula Rilm =  2000 / (Ilimit - 0.04) valid for Rilm = 5kOhm?

Thanks and Best Regards,

Hans

  • 0
    TI__Guru 57737 points

    Hi Hans,

    I would recommend you to not use the device with RILM > 4420 ohms. As you can see in the Electrical Characteristics Table, the device has been characterized with RILM= 4420 ohms. 

    You can expect a current limit between 0.46A and 0.52A with a typical value at 0.49A for a RILM setting of 4420 ohms.

  • 0
    TI__Guru 57737 points

    Hi Hans,

    I would recommend you to not use the device with RILM > 4420 ohms. As you can see in the Electrical Characteristics Table, the device has been characterized with RILM= 4420 ohms. 

    You can expect a current limit between 0.46A and 0.52A with a typical value at 0.49A for a RILM setting of 4420 ohms.

  • 0 in reply to Praveen GD
    TI__Genius 12705 points

    Hi Praveen,

    if the max value of Rilm = 4420Ohm why do we specify a max value of 5000Ohm?

    What happens when using an Rilm of 5k?

    Thanks and Best Regards,

    Hans

  • 0 in reply to Hans
    TI__Guru 57737 points

    Hi Hans,

    For a current limit setting of Rilm = 5 kohms, the current limit circuit will work but the accuracy of the current limit circuit is not characterized and hence  unknown. So, it is recommended to not set a current limit value less than 0.49 A (typ).   

  • 0 in reply to Praveen GD
    TI__Genius 12705 points

    Hi Praveen,

    can you confirm that the  formula Rilm =  2000 / (Ilimit - 0.04) on page 21 data sheet is only valid up to Rilm = 4420Ohm, please?

    Thanks and Best Regards,

    Hans

  • 0 in reply to Hans
    TI__Guru 57737 points

    Hi Hans,

    The current limit formula is valid upto Rilm = 5000 Ohm but as I said the accuracy of current limit setting is known only known till Rilm = 4420 ohms