Magnetic structures for filtering amplifier outputs

An apparatus comprising:

• at least four magnetic cores, each magnetic core supporting an inductor of a filter circuit, and wherein each magnetic core comprises:
• a first section, and
• a second section separated from the first section by an adhesive layer;
• and
• an air-core structure to store magnetic energy, the air-core structure comprising:
• a set of focusing projections that define a hollow cavity, wherein individual focusing projections of the set are disposed on different sides of the hollow cavity to focus magnetic fields from the at least four magnetic cores through the hollow cavity,
• wherein the filter circuit is disposed between an amplifier circuit and a load that is drivable by the amplifier circuit from two sides of the load, and
• wherein multiple outputs of the amplifier circuit are interleaved.

An apparatus comprising:

• an amplifier circuit comprising at least four amplifiers;
• a load driven by the amplifier circuit from two sides of the load;
• and
• a filter circuit comprising:
• at least four inductors that are inductively coupled with one another, each of the inductors comprising a conductor wire wound around a core of magnetic material in a clockwise or anticlockwise direction, the direction of winding for at least two inductors being different from the direction of winding of at least two other inductors,
• a set of focusing projections defining a hollow cavity that stores magnetic energy when subjected to a magnetic flux,
• at least four input terminals, each input terminal for connecting a corresponding one of the at least four inductors to one of the at least four amplifiers;
• and
• at least two output terminals for connecting the filter circuit to the load.

A filter circuit comprising:

• at least four inductors that are inductively coupled with one another, each of the inductors comprising a conductor wire wound around a core of magnetic material in a clockwise or anticlockwise direction, a direction of winding for at least two inductors being different from a direction of winding of at least two other inductors;
• a set of focusing projections defining a hollow cavity that stores magnetic energy when subjected to a magnetic flux;
• at least four input terminals, each input terminal connected to an output of an amplifier corresponding to one of the at least four inductors;
• and
• at least two output terminals for connecting the filter circuit to a load driven from two sides of the load by the amplifiers corresponding to the at least four inductors.

An apparatus comprising:

• at least four magnetic cores, each magnetic core supporting an inductor of a filter circuit, wherein each magnetic core comprises:
• a first section, and
• a second section separated from the first section by an adhesive layer;
• and
• an air-core structure to store magnetic energy, the air-core structure comprising:
• a set of focusing projections that define a hollow cavity, wherein individual focusing projections of the set are disposed on different sides of the hollow cavity to focus magnetic fields from the at least four magnetic cores through the hollow cavity,
• wherein a cross-sectional area of the hollow cavity is substantially equal to a sum of cross-sectional areas of the at least four magnetic cores such that flux distribution in the apparatus is uniform.