Differential Mode Choke Coil With Spaced Plate Core

The patent extracts the plate-shaped core from direct contact with the flanges, creating a spaced configuration where the core is held at a distance (e.g., 0.1-10 mm) from the flange surfaces using adhesive applied only at edge portions. This extraction eliminates the capacitive coupling between the core and flanges while still maintaining the closed magnetic circuit through magnetic flux paths, thereby reducing stray capacitance without compromising magnetic circuit completeness.

The patent introduces an intermediary substance (adhesive) applied selectively at the edge portions of the flanges to hold the plate-shaped core in a spaced position. This intermediary enables the maintenance of the closed magnetic circuit configuration while preventing direct contact that would increase stray capacitance, thus mediating between the conflicting requirements of magnetic circuit completeness and low stray capacitance.

The patent segments the magnetic circuit into a drum-shaped core and a separately positioned plate-shaped core, with the wires wound only around the drum-shaped core. This segmentation allows the magnetic shielding function to be localized to the drum core where the wires are wound, while the plate core provides additional magnetic path completion without directly contributing to signal distortion, as it is spaced from the flanges and not in direct contact with the signal-carrying wires.

The patent applies different spatial configurations to different parts of the magnetic circuit: the drum-shaped core is positioned with wires wound around it for active differential mode blocking, while the plate-shaped core is spaced from the flanges to minimize its interaction with signal fields. This local differentiation optimizes noise suppression at the drum core while minimizing signal distortion effects from the plate core.