Using flexible ferrite sheet to design PCB inductor for 1MHz GaN converter taking into account thermal issues

Inductors are required in switching power converters for energy storage. They take a large volume compared with the other components of converters because of their small energy density. Nowadays, the operating frequency of power converters increases to MHz range because of the fast switching time of the new power GaN transistors. This allows to reduce the volume of the required inductors. In this paper, a design method for PCB inductor for GaN converter is proposed. The design approach is based on the optimization of the inductor volume taking into account the thermal issues of the ferrite sheets used to enhance the inductance value. The required inductance value for the GaN converter is chosen from a Losses-Volume curve. Also, an experimental method based on S-parameters is used to characterize the inductor saturation.