Multi-layer folded high-frequency toroidal inductor windings

Multi-layer windings can effectively decrease losses in inductors and transformers in many applications. We introduce a simple way to achieve lower losses in both air-core and magnetic-core inductors or transformers by incorporating multiple layers, with proper interchange of layer positions to ensure the same flux and current in each layer. We have applied this technique to toroidal inductors, but it can be applied to other winding geometries like windings on E cores or U-U cores. Experimental measurement of an inductor constructed using this approach match predicted performance.