An inductor is integrated into a multilevel wiring network of a semiconductor integrated circuit. The inductor includes a planar magnetic core and a conductive winding. The conductive winding turns around in generally spiral manner on the outside of the planar magnetic core. The conductive winding is piecewise constructed of wire segments and of VIAs. The wire segments pertain to at least two wiring planes and the VIAs are interconnecting the at least two wiring planes. Methods for such integration, and for fabricating laminated planar magnetic cores are also presented.

Disclosed is a litz wire coil that is configured by spirally winding a litz wire on one plane by a predetermined number of turns. The litz wire is configured by twisting together a plurality of enameled wires formed by baking an insulating film on a conducting body. Pressure shaping is performed such that the litz wire has a substantially rectangular shape in cross section, and the flatness ratio of the litz wire in cross section (long side/short side) is controlled at 1.10 to 1.60, preferably 1.20 to 1.40, more preferably 1.25 to 1.35.

Disclosed is a litz wire coil that is configured by spirally winding a litz wire on one plane by a predetermined number of turns. The litz wire is configured by twisting together a plurality of enameled wires formed by baking an insulating film on a conducting body. Pressure shaping is performed such that the litz wire has a substantially rectangular shape in cross section, and the flatness ratio of the litz wire in cross section (long side/short side) is controlled at 1.10 to 1.60, preferably 1.20 to 1.40, more preferably 1.25 to 1.35.

A printed circuit board, and more particularly, a printed circuit board that provides a variable inductance. A printed circuit board includes: an inductor positioned between an input terminal and an output terminal; a switch connected to the inductor; and a controller connected to the output terminal and the switch and outputting a control signal for controlling the switch to the switch, wherein the inductor is formed of a plurality of circuit patterns having different plating thicknesses and signal paths for the plurality of circuit patterns are selectively connected by operation of the switch according to the control signal.

A printed circuit board, and more particularly, a printed circuit board that provides a variable inductance. A printed circuit board includes: an inductor positioned between an input terminal and an output terminal; a switch connected to the inductor; and a controller connected to the output terminal and the switch and outputting a control signal for controlling the switch to the switch, wherein the inductor is formed of a plurality of circuit patterns having different plating thicknesses and signal paths for the plurality of circuit patterns are selectively connected by operation of the switch according to the control signal.

The disclosure features systems for wireless power transfer that include a resonator featuring a coil with at least two windings and at least one inductor having an inductance value, where the at least one inductor is connected in series to at least one of the windings, and where the inductance value is selected so that when the coil carries a current during operation of the system, the at least one inductor maintains a distribution of current flows among the at least two windings such that for each of the at least two windings, an actual current flow in the winding differs from a target current flow for the winding by 10% or less.

In certain aspects, an enclosure for a wireless power transfer pad is disclosed. The enclosure includes a cover shell configured to be positioned over a portion of the wireless power transfer pad configured to face a wireless power receiver when wirelessly transferring power, wherein at least a portion of the cover shell is made of a heat resistant material.

A marker coil includes a flexible substrate, a coil formed on the substrate by wiring, and a substrate holding part that is capable of being attached to a testee. A convex shape is formed in one of the substrate and the substrate holding part, and an engaging part for engaging the convex shape is formed in the other one of the substrate and the substrate holding part.

A transformer can include a flexible substrate having at least a first conductive layer and a dielectric layer. The transformer can further include an unbroken toroidal core of a magnetic material. The magnetic material can include material with a relative magnetic permeability greater than unity. The substrate can include a plurality of planar extensions arranged to provide respective windings encircling the core when the planar extensions are folded and attached back to another region of the substrate. Adjacent windings can be conductively isolated from each other. The flexible substrate can further include a second conductive layer separated from the first conductive layer by the dielectric layer. The first conductive layer and the second conductive layer can be coupled via a plurality of interconnects so that the respective windings are formed when the planar extensions are folded and attached back to the another region of the substrate.

A micromagnetic device includes a first insulating layer formed above a substrate, a first seed layer formed above the first insulating layer, a first conductive winding layer selectively formed above the first seed layer, and a second insulating layer formed above the first conductive winding layer. The micromagnetic device also includes a first magnetic core layer formed above the second insulating layer, a third insulating layer formed above the first magnetic core layer, and a second magnetic core layer formed above the third insulating layer. The micromagnetic device still further includes a fourth insulating layer formed above the second magnetic core layer, a second seed layer formed above the fourth insulating layer, and a second conductive winding layer formed above the second seed layer and in vias to the first conductive winding layer. The first and second conductive winding layers form a winding for the micromagnetic device.