Please refer to the picture attached. For the Regulator LM5146-Q1, the formula for finding the Rlim resistor is mentioned in the datasheet. In the numerator, the minimum current through the low side MOSFET M2 is taken i.e. Iout-delta(iL)/2 . But since, this circuitry is used for overcurrent protection, we feel that the maximum current i.e. Iout+delta(iL)/2 should come instead of Iout-delta(iL)/2 in the numerator. I request you to please explain the logic behind Iout-delta(iL)/2 term in the numerator, because even during the OFF cycle, the maximum current in the below transistor would be Iout+delta(iL)/2