Winding geometrical effects on the high frequency loss of low profile inductor design

This paper summaries the geometrical effects on the winding loss performance of a low profile inductor with spiral coil. Relevant winding loss equations are derived and applied to an optimization algorithm that searches for the design that minimizes the total winding loss at a given core height and footprint area. It has been found that the curves of winding loss versus winding arrangement with different core height show a minimum loss at a critical winding arrangement and core height. Below or above these critical factors, the loss increases drastically. Finally, a new concept of critical frequency is developed to simplify the analysis of AC winding loss of spiral coil