Power inductor and transformer with low acoustic noise air gap

Claim 1

A low acoustic noise power inductive device for high operating frequency power inductor and transformer applications comprising a ferrite magnetic core comprising an essentially rectangular outer member having opposing side sections and connecting end sections and further comprising a cylindrical center member that is continuous in the longitudinal direction, said core end sections having a pair of aligned circular apertures extending completely therethrough into which opposite ends of said cylindrical center member extend to define between at least one end section and the respective end of said center member a radial magnetic air gap of constant predetermined length for controlling the permeability of said core, and a non-magnetic spacer mounted between said one end section and the respective end of said center member to maintain the radial air gap and support said center member, whereby the magnetic forces acting on said core members are radial and substantially sum to zero to result in low acoustic noise, and a winding assembly disposed about said cylindrical center member.