Powder core material coupled inductors and associated methods
A multi-phase coupled inductor includes a powder core material magnetic core and first, second, third, and fourth terminals. The coupled inductor further includes a first winding at least partially embedded in the core and a second winding at least partially embedded in the core. The first winding is electrically coupled between the first and second terminals, and the second winding electrically is coupled between the third and fourth terminals. The second winding is at least partially physically separated from the first winding within the magnetic core. The multi-phase coupled inductor is, for example, used in a power supply.
1. A coupled inductor, comprising:
a monolithic magnetic core formed of a powder magnetic material, the monolithic magnetic core having length, width, and height; and
N windings, N being an integer greater than one;
wherein:
each of the N windings forms an integer number of turns embedded in the monolithic magnetic core, each turn having an u-shape within the monolithic magnetic core as seen when looking cross-sectionally in the widthwise direction,
the turns of each of the N windings are non-overlapping with the turns of each other of the N windings, as seen when looking cross-sectionally in the widthwise direction,
the monolithic magnetic core includes a leakage path portion extending in the length by width directions over the turns of each of the N windings, and
the leakage path portion is non-overlapping with the turns of each of the N windings, as seen when looking cross-sectionally in the widthwise direction.
2. The coupled inductor of claim 1 , wherein the powder magnetic material comprises a magnetic material within a polymeric binder.
3. The coupled inductor of claim 2 , wherein the magnetic material comprises powdered iron.
4. The coupled inductor of claim 1 , each of the N windings being a multi-turn winding.
5. The coupled inductor of claim 1 , each of the N windings being electrically isolated from the other N windings in the monolithic magnetic core.
6. The coupled inductor of claim 1 , the leakage path portion extending along the entire length and width of the monolithic magnetic core.
7. The coupled inductor of claim 6 , the monolithic magnetic core further including a magnetic coupling portion adjoining the leakage path portion in the heightwise direction, the turns of the N windings being disposed in the magnetic coupling portion, but not in the leakage path portion.
8. The coupled inductor of claim 7 , the magnetic coupling portion of the monolithic magnetic core magnetically coupling the N windings, and the leakage path portion of the monolithic magnetic core providing at least part of a path for leakage magnetic flux.
9. The coupled inductor of claim 8 , the magnetic coupling portion having different magnetic properties than the leakage path portion.
10. The coupled inductor of claim 8 , the monolithic magnetic core having opposing first and second outer surfaces separated from each other in the widthwise direction, the turns of each of the N windings being separated, in the widthwise direction, from each of the first and second outer surfaces.
11. The coupled inductor of claim 1 , the monolithic magnetic core including an outer surface extending in the length by width directions, each of the N windings forming two terminals along the outer surface of the monolithic magnetic core.
12. The coupled inductor of claim 1 , wherein:
the monolithic magnetic core has opposing first and second outer surfaces separated from each other in the widthwise direction;
opposing ends of each of the N windings form first and second terminals, respectively;
each first terminal extends towards the first outer surface; and
each second terminal extends toward the second outer surface.
13. The coupled inductor of claim 12 , each first terminal non-overlapping with each second terminal, as seen when looking in the lengthwise direction.
14. A power supply, comprising:
a coupled inductor, including:
a monolithic magnetic core formed of a powder magnetic material, the monolithic magnetic core having length, width, and height, and
N windings, each of the N windings having a first end electrically coupled to a common node, N being an integer greater than one,
wherein:
each of the N windings forms an integer number of turns embedded in the monolithic magnetic core, each turn having an u-shape within the monolithic magnetic core as seen when looking cross-sectionally in the widthwise direction,
the turns of each of the N windings are-non-overlapping with the turns of each other of the N windings, as seen when looking cross-sectionally in the widthwise direction,
the monolithic magnetic core includes a leakage path portion extending in the length by width directions over the turns of each of the N windings, and
the leakage path portion is non-overlapping with the turns of each of the N windings, as seen when looking cross-sectionally in the widthwise direction; and
N switching circuits, each for switching a second end of a respective one of the N windings between at least two different voltage levels at a frequency of at least 20 kilohertz.
15. The power supply of claim 14 , wherein the powder magnetic material comprises a magnetic material within a polymeric binder.
16. The power supply of claim 15 , wherein the magnetic material comprises powdered iron.
17. The power supply of claim 14 , each of the N windings being a multi-turn winding.
18. The power supply of claim 14 , each of the N windings being electrically isolated from the other N windings in the monolithic magnetic core.
19. The power supply of claim 14 , the leakage path portion extending along the entire length and width of the monolithic magnetic core.
20. The power supply of claim 19 , the monolithic magnetic core further including a magnetic coupling portion adjoining the leakage path portion in the heightwise direction, the turns of the N windings being disposed in the magnetic coupling portion, but not in the leakage path portion.
21. The power supply of claim 20 , the magnetic coupling portion of the monolithic magnetic core magnetically coupling the N windings, and the leakage path portion of the monolithic magnetic core providing at least part of a path for leakage magnetic flux.
22. The power supply of claim 21 , the monolithic magnetic core having opposing first and second outer surfaces separated from each other in the widthwise direction, the turns of each of the N windings being separated, in the widthwise direction, from each of the first and second outer surfaces.
23. The power supply of claim 14 , wherein:
the monolithic magnetic core has opposing first and second outer surfaces separated from each other in the widthwise direction;
the first end of each of the N windings extends towards the first outer surface; and
the second end of each of the N windings extends toward the second outer surface.