A power converter and method of controlling a power switch therein to improve power conversion efficiency at low output current. The sensor’s free layer is ribbon shaped and is closely flanked at each long edge by a ribbon of magnetically soft, high permeability material. A seat includes a seat pan that is rotatable over a seat bin between open and closed positions. The voltage regulator can be configured to produce an output voltage having reduced voltage ripple. The formulation is useful in treating Parkinson’s disease and in promoting sexual function.