Selection of the appropriate winding setup in planar inductors with parallel windings

The use of parallel windings in high frequency planar inductors is a common practice. Since the planar technology, commonly PCB layers, limits the maximum layer thickness, the use of parallel windings is usually required in order to reduce the current density and losses. The distribution of the current through each parallel winding depends on the winding positioning and the frequency effects. This effect is especially important in gapped inductors, because the energy stored in the gap region determines the current distribution through the windings. Therefore, the winding positioning is a critical task in order to obtain a balanced current distribution through all the parallel windings.