Coupled inductor arrays and associated methods

• US 9,373,438 B1
• Filed: 03/06/2014
• Issued: 06/21/2016
• Est. Priority Date: 11/22/2011
• Status: Active Grant

• Current Assignee: Volterra Semiconductor LLC (Analog Devices, Inc.)
• Original Assignee: Volterra Semiconductor LLC (Analog Devices, Inc.)
• Inventors: Qiu, Jizheng, Baker, Michael W., Burkhart, Justin Michael, Ikriannikov, Alexandr, Jergovic, Ilija, Burstein, Andrew, Zhak, Serhii Mikhailovich, Miwa, Brett A., Zhou, Xin
• Primary Examiner(s): Lian, Mangtin
• Application Number:
  US14/199,833
• Time in Patent Office: 838 Days
• Field of Search: 336/221, 336/83, 336/233, 336/170, 336/84.C, 336/84.M, 296/06
• US Class Current: 1/1
• CPC Class Codes: H01F 2003/106 Magnetic circuits using combinations of different magnetic materials
• CPC Class Codes: H01F 27/292 Surface mounted devices
• CPC Class Codes: H01F 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12
• CPC Class Codes: H01F 38/08 High-leakage transformers or inductances
• CPC Class Codes: H02M 1/0064 Magnetic structures combining different functions, e.g. storage, filtering or transformation
• CPC Class Codes: H02M 1/14 Arrangements for reducing ripples from dc input or output
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H02M 3/1586 switched with a phase shift, i.e. interleaved

Abstract

A coupled inductor array has length, width, and height. The coupled inductor array includes a monolithic magnetic core formed of a magnetic material having a distributed gap, and a plurality of windings embedded in the monolithic magnetic core. Each winding forms a respective winding loop of one or more turns around a respective winding axis, and each winding axis extends in the height direction. Areas of the monolithic magnetic core enclosed by the winding loops are greater than areas of the monolithic magnetic core outside of the winding loops, as seen when the coupled inductor array is viewed cross-sectionally in the height direction. One possible application of the coupled inductor array is in a multi-phase switching power converter.

Claims

1. A coupled inductor array having length, width, and height, the coupled inductor array comprising:

a monolithic magnetic core formed of a magnetic material having a distributed gap;

a plurality of windings embedded in the monolithic magnetic core, each winding forming a respective winding loop of one or more turns around a respective winding axis, each winding axis extending in the height direction, each winding axis offset from each other winding axis in the widthwise direction; and

one or more magnetic flux impeding structures embedded in the monolithic magnetic core, the one or more magnetic flux impeding structures having a magnetic permeability that is lower than a magnetic permeability of the magnetic material having the distributed gap, the one or more magnetic flux impeding structures being disposed outside of the winding loops, as seen when the coupled inductor array is viewed cross-sectionally in the height direction,

the one or more magnetic flux impeding structures comprising at least one magnetic flux impeding structure disposed outside of each winding loop, in a common lengthwise by widthwise plane with the winding loop, the monolithic magnetic core overlapping with each of the one or more magnetic flux impeding structures, as seen when the coupled inductor array is viewed cross-sectionally in the height direction,

areas of the monolithic magnetic core enclosed by the winding loops and non-overlapping with the winding loops being greater than areas of the monolithic magnetic core outside of the winding loops, as seen when the coupled inductor array is viewed cross-sectionally in the height direction.

2. The coupled inductor array of claim 1, wherein:

the winding loops are separated from each other in the widthwise direction;

each winding loop encloses a respective loop area that is elongated in the lengthwise direction.

3. The coupled inductor array of claim 2, each loop area having a substantially rectangular shape.

4. The coupled inductor array of claim 3, wherein:

each winding loop has a thickness T in the height direction;

adjacent winding loops are separated from each other by a widthwise separation distance D; and

D is less than T.

5. The coupled inductor array of claim 4, D being greater than 0.1*T.

6. The coupled inductor array of claim 1, at least two of the winding loops partially overlapping with each other, as seen when the coupled inductor array is viewed cross-sectionally in the height direction.

7. The coupled inductor array of claim 6, two of the winding loops enclosing a common lengthwise by widthwise area within the monolithic magnetic core.

8. The coupled inductor array of claim 1, the magnetic material having a distributed gap comprising powdered magnetic material within a binder.

9. The coupled inductor array of claim 8, the monolithic magnetic core being a block magnetic core.

10. The coupled inductor array of claim 8, the monolithic magnetic core comprising a plurality of layers of magnetic film stacked in the height direction.

11. The coupled inductor array of claim 1, the one or more magnetic flux impeding structures non-overlapping with the winding loops, as seen when the coupled inductor array is viewed cross-sectionally in the height direction.

12. The coupled inductor array of claim 1, the one or more magnetic flux impeding structures impeding flow of magnetic flux within the monolithic magnetic core in the height direction.

13. A coupled inductor array having length, width, and height, the coupled inductor array comprising:

a monolithic magnetic core formed of a magnetic material having a distributed gap;

a plurality of windings embedded in the monolithic magnetic core, each winding forming a respective winding loop of one or more turns around a respective winding axis, each winding axis extending in the height direction, each winding axis offset from each other winding axis in the widthwise direction; and

one or more magnetic flux impeding structures embedded in the monolithic magnetic core, the one or more magnetic flux impeding structures having a magnetic permeability that is lower than a magnetic permeability of the magnetic material having the distributed gap, the one or more magnetic flux impeding structures being disposed only outside of the winding loops, as seen when the coupled inductor array is viewed cross-sectionally in the height direction,

the one or more magnetic flux impeding structures being formed of an electrically conductive material,

the one or more magnetic flux impeding structures being electrically isolated from the plurality of windings,

the one or more magnetic flux impeding structures non-overlapping with the winding loops, as seen when the coupled inductor array is viewed cross-sectionally in the height direction, and

the monolithic magnetic core overlapping with each of the one or more magnetic flux impeding structures, as seen when the coupled inductor array is viewed cross-sectionally in the height direction.

14. The coupled inductor array of claim 13, the one or more magnetic flux impeding structures and the plurality of windings being formed of a common material.