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TPS25946: SLVRBH8 Calculation Tool for TPS25946 Current Limit

Eric Adams
Prodigy 30 points

Part Number: TPS25946

Why does the SLVRBH8 Design Calculation Tool for TPS25946 increase the current limit by 10.5% when calculating the value for RILM_Cal?

Also is this 10.5% value applicable when the part is used under 1A when the current limit threshold accuracy changes?

 

  • 0
    TI__Expert 7860 points

    Hi Eric,


    Eric Adams said:

    Why does the SLVRBH8 Design Calculation Tool for TPS25946 increase the current limit by 10.5% when calculating the value for RILM_Cal?

    The ILIM has an accuracy of 10%. So if continuous current is 1A , it is recommended to put ILIM as 1.105A since because of accuracy of ILIM pin , the ILIM can be brought down till 1.05A  by device , not effecting continuous current mode

    Eric Adams said:

    Also is this 10.5% value applicable when the part is used under 1A when the current limit threshold accuracy changes?

    Yes , actually the accuracy drops till 15% when ILIM<1A , you can check graphs in the datasheet

    Best Regards

    Sailendra

  • 0
    Prodigy 30 points

    So if my objective for the TPS25946 is to limit the current to a maximum of 750mA should I set ILIM to 652mA? 

    652mA * 1.15 = 750mA

    The 1.15 factor is for a possible 15% increase in current the TPS25946 would allow.

    Please confirm for a situation where the current cannot be allowed to exceed 750mA.

  • 0 in reply to Eric Adams
    TI__Expert 7860 points

    Hi Eric ,

    When you put ILIM for 650mA, the device tries to limit current around 650mA mostly. But in worst case also , the device never allows current more than 750mA

    Best Regards,

    Sailendra