Automatic tuning of coupled inductor filters

A coupled inductor filter is presented with interesting notch mode filtering characteristics. Although this configuration has been long established, it has received little attention. The new contribution of this paper is to provide an automatic tuning process that can make use of the frequency domain characteristics of the coupled inductor building block. In a sense, this becomes an "active" filter technique that uses passive elements for implementation. The combination offers potential performance improvements in comparison with active filters.