A coupled inductor or a flyback-type transformer is required for flybuck topology. Calculate the minimum primary turns for a flyback-type transformer using Equation 23.

where

• B_max is the maximum flux density.
• A_e is the effective core area of the chosen transformer.

In this design, the 750345248 inductor from Würth is selected for the transformer. Würth offers many other flyback-type transformers and ready-made coupled inductors, in a variety of standard values, saturation currents, and sizes.