SNVS783K January 2012 – August 2021 LM5017
The minimum inductance is selected to limit the output ripple to 15 to 40 percent of the maximum load current. In addition, the peak inductor current at maximum load should be smaller than the minimum current limit as given in Section 6.5 table.
The inductor current ripple is given by Equation 13.
The maximum ripple is observed at maximum input voltage. Substituting VIN = 95 V and ΔIL = 40 percent × IOUT (max) results in L1 = 198 μH. The next higher standard value of 220 μH is chosen. The peak-to-peak minimum and maximum inductor current ripple are 40 mA and 181 mA at the minimum and maximum input voltages respectively. The peak inductor and switch current is given by Equation 14.
690 mA is less than the minimum current limit threshold of 0.7 A. The selected inductor should be able to withstand the maximum current limit of 1.3 A during startup and overload conditions without saturating.