Hello~
According to LM5117's "Description & parametrics" page (http://www.ti.com/product/LM5117#parametrics), "Iout (Max) (A)" value is "20".
And, also "WEBENCH® LM5117" tool has Iout range is upto 17A.
I think that this device will be able to flow the larger current (>25A) to changing the sensing resistor value.
If that does not, I'd like to know the reasons.
Thanks... C.W. :)