Composite magnetic core for switch-mode power converters

A magnetic core, comprising:

• a base;
• first and second legs on the base and separated from each other;
• a center leg on the base and separated from said first and second legs;
• and
• a plate on said first, second and center legs opposite the base, a plurality of windings around the first and second legs that when energized generate flux that adds together at a location in the base, center leg and said plate;
• wherein a portion of at least one of said base, center leg and said plate at said location comprises a first material having a first saturation flux density (BSAT1) and a first magnetic permeability (μrel1) and the remaining portion of the magnetic core comprises a second material having a second magnetic permeability (μrel2) greater than the first by at least a factor of 10.

A magnetic core, comprising:

• a base;
• first and second legs on the base and separated from each other;
• a center leg on the base and separated from said first and second legs;
• and
• a plate on said first, second and center legs opposite the base, wherein a portion of said center leg comprises a first material having a first saturation flux density (BSAT1) and a first magnetic permeability (μrel1) and the remaining portion of the magnetic core comprises a second material having a second magnetic permeability (μrel2) greater than the first by at least a factor of 10 and
• a plurality of primary and secondary windings around the first and second legs that when energized produce a transformer flux component that circulates around the first and second legs, base and plate in a high permeability path and inductor flux components that circulate around said first or second legs, the base, the center leg and the plate in a low permeability path and add together in said portion of said center leg.

A magnetic core, comprising:

• a base;
• a plurality of outer legs located along a first outer edge of the base and separated from each other
• a center leg on the base and located along an opposite outer edge of the base and separated from the outer legs;
• and
• a plate on said outer and center legs opposite the base,
• a plurality of windings around the outer legs that when energized generate flux that adds together in the base, center leg and said plate;
• wherein a portion of at least one of said base, center leg and said plate at said location comprises a first material having a first saturation flux density (BSAT1) and a first magnetic permeability (μrel1) and the remaining portion of the magnetic core comprises a 3 second material having a second magnetic permeability (μrel2) greater than the first by at least a factor of 10.

A magnetic core, comprising:

• a base;
• a plurality of outer legs located along a first outer edge of the base and separated from each other
• a center leg on the base and located along an opposite outer edge of the base and separated from the outer legs;
• and
• a plate on said outer and center legs opposite the base, wherein a portion of said center leg comprises a first material having a first saturation flux density (BSAT1) and a first magnetic permeability (μrel1) and the remaining portion of the magnetic core comprises a second material having a second magnetic permeability (μrel2) greater than the first by at least a factor of 10;
• a plurality of primary and secondary windings around the outer legs that when energized produce a transformer flux component that circulate around said outer legs, base and plate in a high permeability path and inductor flux components that circulate around said outer legs, the base, the center leg and the plate in a low permeability path and add together in said portion of said center leg.