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Original question:

TPS274160: Maximum Current Limit Resistor Value

TPS272C45: Setting Current Limit below Minimum Specified in Datasheet

Grace Eysenbach
Prodigy 50 points
Part Number: TPS272C45
Other Parts Discussed in Thread: TPS2H000-Q1

Hi,
I see on the datasheet that the max Rclim value is 28.2k, which results in a current limit of ~727mA. 

Rlim = Kcl / Icl --> 28.2k = 20.5 / Icl --> Icl = 727mA

For my application I require the channels to be current limited to 500mA or below (Rlim = 20.5 / .500 = 41k) . If I place a Rclim = 41k to produce Ilim = 500mA I have two questions:

1) will the device be able to current limit to this lower level?

2) If so, how will the accuracy be impacted? (I am willing to compromise on accuracy in order to achieve this current limiting) 

Thanks! 



  • 0
    TI__Mastermind 34925 points

    Grace,

    It is not recommended to set the current limit above the max specified resistor of 28.2k. This is because if the resistance is too high then the device runs the risk of defaulting to the "internal" current limit. This is the default current limit that is set if the ILIMx pins are floating and is a much higher value.

    Do you have an explicit need for an industrial-centric device? The TPS2H000-Q1 would work here too as the current limit is rated down to 50mA. It's an automotive device, however functionally it would also work in any relevant end equipment.