Efficient Core Utilization Methods in Planar Magnetic Components

Traditionally magnetic component are constructed using copper wires wound around the core using a bobbin. Windings in planar magnetic components are constructed utilizing PCB traces, as opposed to conventional magnetic components. In practice, planar magnetic designers prefer to use two-layer PCBs considering its modularity and cost. Connecting the PCBs in parallel increases current carrying capability, while connecting in series ensures that the design achieves the required number of turns. There are many methods possible to effectively utilize the core for placing the turns. In this paper, three methods are proposed to occupy the turns in the core window viz. standard method, stretched method and staggering methods. In standard method, the via required for the transpose of the strands occupies a space within the center window limb of an E-core, where as in the other two methods it can stretch beyond the space of center limb. As a result, stretch and staggered design can be scaled down the magnetics to a smaller form factor with improved core utilization.