ZHCSBB6H April 2012 – November 2017 LM34927
PRODUCTION DATA.
A coupled inductor or a flyback-type transformer is required for this topology. Energy is transferred from primary to secondary when the low-side synchronous switch of the buck converter is conducting.
The maximum inductor primary ripple current that can be tolerated without exceeding the buck switch peak current limit threshold (0.7 A minimum) is given by Equation 14.
Using the maximum peak-to-peak inductor ripple current ΔIL1 from Equation 14, the minimum inductor value is given by Equation 15.
A higher value of 33 µH is selected to insure the high-side switch current does not exceed the minimum peak current limit threshold. With this inductance, the inductor current ripple is ΔIL1= 0.36 A at the maximum VIN.