Abstract: A high-frequency transformer is constructed from a flexible circuit comprising a primary conductive film winding and one or more secondary conductive film windings disposed on a single dielectric membrane. The flexible circuit is folded to form a stack of primary winding layers interleaved with secondary winding layers and then inserted into a mangetic cup core. The flexible circuit is preferably patterned photolithographically.

Abstract: A conductive film magnetic component such as an inductor or transformer includes a conductive film winding having a generally serpentine configuration when disposed in a plane. This film is folded to form a stack of layers with each "layer" comprising part of a winding turn and with successive "layers" connected at the folds via the continuous conductive film. The conductive film may be self-supporting and coated with a dielectric layer or may be disposed on a dielectric membrane. The film and membrane are preferably patterned photolithographically.

Abstract: A dual-permeability magnetic core structure is provided for use in small, high-frequency inductors and transformers. The dual-permeability core encloses a winding window containing planar windings and comprises high-permeability and low-permeability sections positioned to produce a highly uniform, or uniformly varying, magnetic field on the winding surfaces. The dual-permeability core products low winding losses and a low AC-to-DC resistance ratio. Fabrication of the dual-permeability core involves a method of controlling the permeability of a magnetic material and a methd of combining structures of two different permeability values.

Abstract: A high-frequency transformer is constructed from a flexible circuit comprising a primary conductive film winding and one or more secondary conductive film windings disposed on a single dielectric membrane. The flexible circuit is folded to form a stack of primary winding layers interleaved with secondary winding layers and then inserted into a magnetic cup core. The flexible circuit is preferably patterned photolithographically.