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Original question:

LM3481-Q1: Capacitor charge solution

LM3481-Q1: Rsense value change question.

CHO SR
Genius 3415 points
Part Number: LM3481-Q1

Tool/software:

Hi,

We made WEBENCH with the specifications that customers want.

6138.WBDesign86.pdf

The Rsense value is 2.46928 mOhm.

2.46928 mOhm is a custom specification, so I want to change it to a different value.

The value you want to change is outside the value you are recommending in WEBENCH.

If I change the Rsense value to 2mohm or 3mohm, what kind of problems do I get?

  • +1
    TI__Mastermind 26930 points

    Hi Cho,

    Thanks for using the e2e forum.

    There is no physical resistance component with this exact value, so it makes sense to choose a resistance of 2mOhm or 3mOhm instead.
    The effect on the device itself is that the peak current limit is changed (The point, where the device triggers overcurrent protection and starts limiting the duty cycle).

    Whether 2mOhm or 3mOhm is more suited depends on the expected load conditions from customer. We generally recommend to go with the lower value, so OCP is not triggered accidentally during normal operation.

    You can also use our quickstart calculator tool to see the maximum current limits based on different sense resistors:
    https://www.ti.com/tool/download/LM3481-BOOST-CALC

    Best regards,
    Niklas