Multilayer inductor and transformer

Abstract

A planar transformer located in a reference plane defining azimuthal and radial directions in orthogonal planes includes a planar first coil portion and a planar core portion. The first coil portion is disposed in the reference plane and includes concentric first coil loops having an innermost first coil loop and an outermost first coil loop. Each of the first coil loops includes an elongated first layer. The elongated first layer includes at least one electrically conductive first layer and at least one adhesive first layer. The core portion is disposed in the reference surface and at least partially disposed in an opening defined by the innermost first coil ring, and has a plurality of second layers stacked in one of a radial direction and a height direction orthogonal to the reference surface. The plurality of second layers includes at least one magnetically conductive second layer and at least one adhesive second layer.

Description

Summary of the Invention

[0001] In some aspects of this specification, a generally planar transformer is provided, which is generally located in a reference plane defining mutually orthogonal azimuth and radial directions, and includes a generally planar first coil portion and a generally planar core portion. The generally planar first coil portion is generally disposed in the reference plane and includes a plurality of substantially concentric first coil loops having an innermost first coil loop and an outermost first coil loop. Each of the first coil loops includes a plurality of elongated first layers that extend and lengthen in the azimuth direction and are stacked in the radial direction. The plurality of elongated first layers includes at least one conductive first layer and at least one adhesive first layer. The generally planar core portion is generally disposed in the reference plane and is at least partially disposed in an opening defined by the innermost first coil loop of the first coil portion, and includes a plurality of second layers stacked in one of the radial direction and a height direction orthogonal to the reference plane. The plurality of second layers includes at least one magnetically conductive second layer and at least one adhesive second layer.

[0002] In some aspects of this specification, a transformer is provided, comprising conductive primary and secondary coils stacked along a height direction and electrically isolated from each other. A first coil portion and a second coil portion define respective first and second central openings aligned with each other along a height direction. A core is disposed within the first and second central openings and comprises a plurality of substantially planar, commonly extending, magnetically conductive layers, the total number of which is at least 10, bonded together and stacked along a height direction.

[0003] In some aspects of this specification, a magnetically conductive core for use in a transformer is provided, the magnetically conductive core having an average height H1 in the height direction and a maximum lateral dimension D1, such that D1 / H1 is greater than or equal to about 2. The magnetically conductive core comprises a plurality of substantially planar and commonly extending magnetically conductive alloy layers, the number of which is at least 50 in total, stacked laterally and bonded to each other via a plurality of adhesive layers. The magnetically conductive alloy layers are intentionally fractured substantially throughout these layers to form a plurality of magnetically conductive alloy islands isolated from each other by a plurality of interconnecting cracks.

[0004] In some aspects of this specification, a method for manufacturing a magnetically conductive core for use in a transformer is provided, the method comprising the steps of: providing a multilayer film having a plurality of alternating magnetically conductive alloy layers and adhesive layers; winding the multilayer film around a longitudinal axis to form a wound multilayer film having a plurality of substantially concentric turns of the multilayer film substantially centered on the longitudinal axis; and cutting the wound multilayer film into at least one slice along a parallel radial plane to form a core.

[0005] In some aspects of this specification, a method for manufacturing a magnetically conductive core for use in a transformer is provided, the method comprising the steps of: providing a multilayer stack having a plurality of alternating magnetically conductive alloy layers and adhesive layers stacked along a first direction; and slicing the multilayer stack into at least one slice along a parallel plane orthogonal to the first direction to form a core. Attached Figure Description

[0006] Figures 1A to 1C A generally planar view of a transformer according to one embodiment of this specification is provided;

[0007] Figures 2A to 2D Additional views of a generally planar transformer according to one embodiment of this specification are provided;

[0008] Figures 3A to 3B This is an image of a second magnetically conductive layer that has been intentionally fractured to form cracks defining islands capable of conducting magnetism, according to one embodiment of this specification.

[0009] Figures 4A to 4B This illustration shows how the surface of a magnetically conductive core according to one embodiment of this specification can include a regular pattern of parallel features;

[0010] Figure 5 An example is illustrated by one embodiment of this specification of a method for manufacturing a magnetically conductive core for use in a transformer; and

[0011] Figure 6 Another method for manufacturing a magnetically conductive core for use in a transformer is illustrated according to one embodiment of this specification. Detailed Implementation

[0012] Reference is made in the following description to the accompanying drawings, which form part of this disclosure and in which various embodiments are illustrated by way of example. The drawings are not necessarily drawn to scale. It should be understood that other embodiments may be conceived and practiced without departing from the scope or spirit of this specification. Therefore, the following detailed description should not be considered limiting.

[0013] Inductors or transformers are fundamental components in power electronic devices, especially in power conversion circuits such as AC-DC and DC-DC converters. They are also components in EMI filters (e.g., common-mode and differential-mode noise filters). They typically consist of loops made of electrical conductors (e.g., wires or conductive patterns) with a core material of magnetic materials (e.g., NiZn ferrite, MnZn ferrite, nanocrystals, etc.). Litz wire or solid copper wire is commonly used to construct the conductive loops of inductors and transformers.

[0014] Transformers like these experience power losses due to the skin effect and proximity effect of the core material, as well as magnetic losses. At high frequencies, the losses experienced by inductors can increase significantly. Wire coils can be embedded in printed circuit boards, but the thinness of the transformer is limited by the conductor of the coil. Many applications are seeking transformers that are more stable, thinner, and lighter.

[0015] It should be noted that, as used throughout this specification, the term "transformer" should be assumed to include both transformers and inductors. That is, various embodiments of the transformer described herein can also be suitably used as inductors. For example, the primary coil described elsewhere herein can be used as a single inductor in a particular application, and in embodiments described as having both a first (primary) coil and a secondary coil, the coil can be used as a coupled inductor in a particular application.

[0016] According to some aspects of this specification, a novel design is provided in which the magnetic core is constructed as an epoxy resin-based ferromagnetic core having an alternating structure of magnetically conductive layers and adhesive layers. For the purposes of this specification, the term "adhesive" shall refer to any suitable adhesive or bonding component, including organic and inorganic adhesives. This approach produces a magnetic core that exhibits increased thermal reliability and mechanical strength, can be reduced in thickness, is flexible and easy to handle without stress-induced fracture during handling, and is less expensive to produce than existing core solutions.

[0017] According to some aspects of this specification, the generally planar transformer is generally located in a reference plane (e.g., the xy plane in a Cartesian coordinate system, where the z-direction is the thickness direction) that defines mutually orthogonal azimuth and radial directions. In some embodiments, the generally planar transformer may include a first coil portion (e.g., a primary coil) and a core portion of the generally planar structure.

[0018] In some embodiments, the generally planar first coil portion may be substantially disposed in a reference plane and include a plurality of substantially concentric first coil loops. In some embodiments, the first coil loops may include an innermost first coil loop and an outermost first coil loop. In some embodiments, each of the first coil loops may include a plurality of elongated first layers that extend and lengthen in an azimuth direction and are stacked in a radial direction. In some embodiments, the plurality of elongated first layers may include at least one conductive first layer and at least one adhesive first layer.

[0019] In some embodiments, the generally planar core portion may be disposed substantially within a reference plane and at least partially within an opening defined by the innermost first coil loop of the first coil portion. The generally planar core portion may include a plurality of second layers stacked in one of a radial direction and a height direction orthogonal to the reference plane (e.g., the z-axis). In some embodiments, the plurality of second layers may include at least one magnetically conductive second layer and at least one adhesive second layer.

[0020] In some embodiments, the generally planar first coil portion may include a first multilayer film extending between opposing first and second longitudinal ends of the first multilayer film and wound to form a plurality of substantially concentric first coil loops. In some embodiments, one of the innermost and outermost first coil loops may include the first longitudinal end of the first multilayer film, and the other of the innermost and outermost first coil loops includes the second longitudinal end of the first multilayer film. For example, the first multilayer film may be wound around itself to create concentric loops, wherein one end of the film is inside the wound film (on the innermost layer), and the other end of the film is outside the wound film (on the outermost layer). In some embodiments, the first and second longitudinal ends of the first multilayer film may be electrically connected to corresponding first and second conductive terminals.

[0021] In some embodiments, the permeability of any first layer in the plurality of extended first layers of each first coil ring may be substantially less than the permeability of at least one magnetically conductive second layer among the plurality of second layers. In some embodiments, the conductivity of any second layer in the plurality of second layers is substantially less than the conductivity of at least one conductive first layer among the plurality of extended first layers of each first coil ring.

[0022] In some embodiments, the plurality of extended first layers of each first coil ring in the first coil ring may further include at least one magnetically conductive first layer. In some embodiments, the plurality of extended first layers of each first coil ring in the first coil ring may further include at least one non-adhesive electrically insulating first layer.

[0023] In some embodiments, the plurality of second layers may further include at least one conductive second layer. In some embodiments, the plurality of second layers may further include at least one non-adhesive, electrically insulating second layer.

[0024] In some embodiments, the generally planar coil portion and the generally planar core portion may be at least partially embedded in an electrically insulating and non-magnetic substrate. In some such embodiments, the substrate may include a flame retardant 4 (FR4) substrate. In some such embodiments, the generally planar transformer may also include at least one grounding layer embedded in the substrate.

[0025] It should be noted that, as used herein, the term “magnetic” refers to a material with a relative permeability greater than or equal to about 2.0 (i.e., “magnetic material”), and the term “non-magnetic” refers to a material with a relative permeability of about 1.0 (i.e., “non-magnetic material”).

[0026] In some embodiments, the second layer in the generally planar core portion may be stacked along the height direction. In other embodiments, the second layer in the generally planar core portion may be stacked along the radial direction.

[0027] In some embodiments of the generally planar transformer, it may further include a generally planar second coil portion (e.g., a secondary coil) substantially disposed in a reference plane and having a plurality of substantially concentric second coil loops. In some embodiments, the substantially concentric second coil loops may include an innermost second coil loop and an outermost second coil loop. In some embodiments, each of the second coil loops may include a plurality of elongated third layers that extend and extend in an azimuth direction and are stacked in a radial direction. In some such embodiments, the plurality of elongated third layers may include at least one conductive third layer and at least one adhesive third layer. In some such embodiments, the generally planar core portion may be at least partially disposed in an opening defined by the innermost second coil loop of the second coil portion. In some such embodiments, the generally planar second coil portion may include a second multilayer film extending between opposing first and second longitudinal ends of the second multilayer film and wound to form a plurality of substantially concentric second coil loops. In some embodiments, one of the innermost and outermost second coil loops includes a first longitudinal end of the second multilayer film, and the other of the innermost and outermost second coil loops includes a second longitudinal end of the second multilayer film. In some such embodiments, the first and second longitudinal ends of the second multilayer film may be electrically connected to corresponding third and fourth conductive terminals.

[0028] In some embodiments, at least one conductive first layer of a generally planar transformer may comprise a metal. In some such embodiments, the metal may comprise one or more of aluminum, titanium, copper, silver, and gold.

[0029] In some embodiments, at least one magnetically conductive second layer of a generally planar transformer may comprise one or more of a magnetically conductive ferrite, a soft magnetic material, a metal, a crystalline alloy, a nanocrystalline alloy, an amorphous alloy, and a composite material. In some such embodiments, the magnetically conductive ferrite may comprise one or more of manganese-zinc ferrite and nickel-zinc ferrite. In some such embodiments, the magnetically conductive metal may comprise an iron-containing alloy. In some such embodiments, the magnetically conductive alloy may further comprise one or more of silicon, aluminum, boron, niobium, copper, cobalt, nickel, and molybdenum. In other such embodiments, the magnetically conductive alloy further comprises one or more of silicon, boron, niobium, and copper.

[0030] In some embodiments, the magnetically permeable crystalline alloy may include two or more of iron, cobalt, and nickel. In some embodiments, the magnetically permeable nanocrystalline alloy may include iron, silicon, boron, niobium, and copper. In some embodiments, the magnetically permeable amorphous alloy may include cobalt or iron, and one or more of silicon and boron.

[0031] In some embodiments, the magnetically conductive composite material may include particles dispersed in a binder. In some such embodiments, the particles may include metal particles. In some such embodiments, the metal particles may include an iron-aluminum-silicon alloy.

[0032] In some embodiments, at least one magnetically conductive second layer may be intentionally fractured substantially throughout the second layer to form multiple interconnecting cracks defining multiple magnetically conductive islands.

[0033] In some embodiments, the generally planar core portion may include at least 10, at least 20, at least 50, at least 75, at least 100, at least 150, at least 200, at least 250, at least 300, at least 350, or at least 400 spaced-apart magnetically conductive second layers. In some embodiments, each of the at least one magnetically conductive second layer may have an average thickness greater than about 0.3 micrometers, or greater than about 0.4 micrometers, or greater than about 0.5 micrometers, or greater than about 1 micrometer, or greater than about 2 micrometers, or greater than about 5 micrometers, or greater than about 7 micrometers, or greater than about 10 micrometers, or greater than about 15 micrometers. In some embodiments, each of the at least one magnetically conductive second layer may have an average thickness less than about 50 micrometers, or less than about 45 micrometers, or less than about 40 micrometers, or less than about 35 micrometers, or less than about 30 micrometers, or less than about 25 micrometers. In some embodiments, each of at least one first adhesive layer and the second adhesive layer may have an average thickness of less than about 20 micrometers, or less than about 15 micrometers, or less than about 10 micrometers.

[0034] In some embodiments, viewed from a top plan view (e.g., downward along the z-axis or the thickness direction of the transformer), the core portion of the generally planar surface may have an elliptical, circular, square, rectangular, or any other suitable shape. In some embodiments, the core portion of the generally planar surface may define a central opening extending across the entire thickness of the core portion. In some embodiments, the core portion of the generally planar surface may include a plurality of repeating units stacked in one of the radial and vertical directions. In some such embodiments, each repeating unit may include a magnetically conductive second layer and an adhesive second layer. In some such embodiments, the core portion of the generally planar surface may have at least 20, or at least 50, or at least 75, or at least 100, or at least 200, or at least 300, or at least 400 repeating units. In some embodiments, the core portion of the generally planar surface may be electrically isolated from the first coil portion of the generally planar surface. In some embodiments, the core portion of the generally planar surface may be electrically grounded.

[0035] In some embodiments, the maximum lateral dimension D1 of the generally planar core portion may be less than about 50 mm, or less than about 45 mm, or less than about 40 mm, or less than about 35 mm, or less than about 30 mm, or less than about 25 mm, or less than about 20 mm, or less than about 15 mm, or less than about 10 mm. In some embodiments, the maximum lateral dimension D2 of the generally planar first coil portion is less than about 50 mm, or less than about 45 mm, or less than about 40 mm, or less than about 35 mm, or less than about 30 mm, or less than about 25 mm, or less than about 20 mm, or less than about 15 mm, or less than about 10 mm.

[0036] In some embodiments, the generally planar transformer may further include a generally planar third coil portion having an elongated third multilayer film extending along its length L1 between opposing first and second longitudinal ends, and wound in an azimuth direction to form a plurality of substantially concentric third coil loops arranged radially and including an innermost third coil loop and an outermost third coil loop. In some embodiments, the innermost third coil loop may include a first longitudinal end of the third multilayer film, and the outermost third coil loop may include a second longitudinal end of the third multilayer film. In some embodiments, the elongated third multilayer film may include a plurality of elongated third layers having at least one magnetically conductive third layer and at least one adhesive third layer. In some embodiments, the generally planar first coil portion and the generally planar core portion are at least partially disposed in an opening defined by the innermost third coil loop of the generally planar third coil portion. In some such embodiments, the maximum lateral dimension D3 of the third coil portion in the generally planar plane may be less than about 200 mm, or less than about 175 mm, or less than about 150 mm, or less than about 125 mm, or less than about 100 mm, or less than about 75 mm, or less than about 50 mm, or less than about 45 mm, or less than about 40 mm, or less than about 35 mm, or less than about 30 mm. In some embodiments, the average height H1 of the core portion in the generally planar plane along the height direction (e.g., the z-axis) is less than about 10 mm, or less than about 9 mm, or less than about 8 mm, or less than about 7 mm, or less than about 6 mm, or less than about 5 mm, or less than about 4 mm, or less than about 3 mm, or less than about 2 mm, or less than about 1 mm.

[0037] According to some aspects of this specification, a transformer includes conductive primary and secondary coils stacked along a height direction (e.g., the z-axis of the transformer) and electrically isolated from each other, as well as a core. In some embodiments, the first coil portion and the second coil portion may define respective first and second center openings aligned with each other along the height direction. In some embodiments, the core may be disposed within the first and second center openings and may include a plurality of substantially planar (e.g., in the xy-plane of the transformer) and co-extending magnetically conductive layers, the number of which is at least 10, or at least 25, or at least 50, or at least 75, or at least 100, or at least 150, or at least 200, or at least 250, or at least 300, or at least 350, or at least 400, and are coupled to each other and stacked along the height direction. In some embodiments, the core may have an average height H1 in the height direction and a maximum lateral dimension D1, such that the ratio D1 / H1 is greater than or equal to about 2, about 3, about 4, about 5, about 10, about 15, or about 20. In some embodiments, the core may be disc-shaped.

[0038] In some implementations, the magnetically conductive layers may be intentionally fractured substantially as a whole to form multiple interconnected cracks defining multiple magnetically conductive islands.

[0039] According to some aspects of this specification, a magnetically conductive core for use in a transformer may have an average height H1 in the height direction and a maximum lateral dimension D1, such that the ratio D1 / H1 is greater than or equal to about 2, about 3, about 4, about 5, about 10, about 15, or about 20. In some embodiments, the magnetically conductive core may comprise a plurality of substantially planar (e.g., xy-plane) and commonly extending magnetically conductive alloy layers, the number of which is at least 50, at least 75, at least 100, at least 150, at least 200, at least 250, at least 300, at least 350, or at least 400, stacked laterally and bonded to each other via a plurality of adhesive layers. In some embodiments, the magnetically conductive alloy layers may be intentionally fractured substantially entirely to form a plurality of magnetically conductive alloy islands isolated from each other by a plurality of interconnecting cracks.

[0040] In some embodiments, the magnetically conductive alloy layer may comprise a magnetically conductive nanocrystalline alloy. In some such embodiments, the nanocrystalline alloy may comprise one or more of iron, silicon, boron, niobium, and copper. In some embodiments, the magnetically conductive core may have a disk, toroidal, donut, elliptical, or coil shape. In embodiments where the magnetically conductive core is disk-shaped, the disk-shaped core may have at least one central through-hole. In some embodiments, the core has an elliptical, circular, square, or rectangular shape when viewed along the height direction.

[0041] In some embodiments, each of the magnetically conductive alloy layers may have an average thickness between about 0.3 micrometers, or about 0.4 micrometers, or about 0.5 micrometers, or about 1 micrometer, or about 1.5 micrometers, or about 2 micrometers, or about 2.5 micrometers, or about 3 micrometers and about 50 micrometers, or about 45 micrometers, or about 40 micrometers, or about 35 micrometers, or about 30 micrometers. In some embodiments, each of the adhesive layers may have an average thickness between about 0.5 micrometers, or about 1 micrometer, or about 1.5 micrometers, or about 2 micrometers and about 20 micrometers, or about 15 micrometers, or about 10 micrometers. In some embodiments, H1 may be less than about 10 mm, or about 9 mm, or about 8 mm, or about 7 mm, or about 6 mm, or about 5 mm, or about 4 mm, or about 3 mm.

[0042] In some embodiments, at least one of the opposing top and bottom main surfaces of the core may include a regular pattern comprising a plurality of substantially parallel features across the main surfaces. In some such embodiments, at least one of the features is a groove or similar linear workpiece or structure. In some embodiments, including a groove or similar feature can increase the surface area, which can improve adhesion when the core is embedded in another material. These features can also be shown to improve CTE (coefficient of thermal expansion) mismatch in components assembled from multiple material types.

[0043] According to some aspects of this specification, a method for manufacturing a magnetically conductive core for use in a transformer includes the following steps: providing a multilayer film having a plurality of alternating magnetically conductive alloy layers and adhesive layers; winding the multilayer film around a longitudinal axis to form a wound multilayer film having a plurality of substantially concentric turns of the multilayer film substantially centered on the longitudinal axis; and cutting the wound multilayer film into at least one slice along a parallel radial plane to form a core. In some embodiments, the cutting includes one or more of sawing, laser cutting, waterjet cutting, and die cutting. In some embodiments, the method further includes the step of intentionally fracturing the magnetically conductive alloy layers over the entirety of the layers to form a plurality of interconnected cracks defining a plurality of magnetically conductive islands in each of the layers.

[0044] According to some aspects of this specification, a method for manufacturing a magnetically conductive core for use in a transformer includes the steps of: providing a multilayer stack having a plurality of alternating magnetically conductive alloy layers and adhesive layers stacked along a first direction; and cutting the multilayer stack into at least one slice along a parallel plane orthogonal to the first direction to form a core. In some embodiments, the cutting may include one or more of sawing, laser cutting, waterjet cutting, and die cutting. In some embodiments, the method may further include the step of: intentionally fracturing the magnetically conductive alloy layers throughout the layers to form a plurality of interconnecting cracks prior to forming the multilayer stack, such that in each of the layers, the plurality of interconnecting cracks may define a plurality of magnetically conductive islands.

[0045] Now turn to the attached diagram. Figures 1A to 1C A general planar view of the transformer is provided according to this specification. Figures 2A to 2D Additional views of the same embodiment of the transformer in a generally planar shape are provided. Each of these figures (1A to 1C, 2A to 2D) can be referred to in the following discussion, and these figures should be examined concurrently for the purpose of the following discussion.

[0046] In some implementations, the generally planar transformer 300 is located on a reference plane (e.g., by...). Figure 1A In the Cartesian coordinate system (defined in the xy plane), and defining mutually orthogonal in-plane azimuth directions 30 and radial directions 31 (see, for example, see...). Figure 1A The coordinate system defined by directions 30 and 31, and Figure 2A (Directions 30 and 31 in the middle). In some embodiments, the generally planar transformer 300 includes a generally planar first coil portion 10 (e.g., a primary coil) and generally planar core portions 20, 21.

[0047] Please note, Figure 1AThe core portion 20 in one orientation is shown, and Figure 1B Core portion 21 in different orientations is shown. For the majority of the rest of the discussion, for simplicity, the core portion will be referred to as core portion 20, unless the orientation shown for core portion 21 is specifically discussed. Reference indicator 20 and reference indicator 21 are used interchangeably when discussing the core portion, except for orientation.

[0048] It should also be pointed out that, with Figure 2A (This is a top view of the planar transformer 300) Conversely, it is shown that... Figure 1A This is a cross-sectional view of one embodiment of the planar transformer 300. That is, if... Figure 2A The planar transformer 300 is cut in half (along a line parallel to the x-direction or radial direction 31, such as...) Figure 2A (as shown), then Figure 1A Will Figure 2A The planar transformer 300 is shown as a cross-sectional view. Therefore, in Figure 2A The first coil portion 10, as shown in the top plan view, is a ring shape. Figure 1A When viewed in a cross-sectional view, the first coil portion 10 appears as two segments, one segment of which is located to the left of the core portion 20, and the other segment of which is located to the right of the core portion 20. The same applies to the generally planar second coil portion 60 and the generally planar third coil portion 70, which are discussed elsewhere in this document.

[0049] In some embodiments, the core portion 20 may include a plurality of substantially planar (e.g., in the xy plane, such as) Figure 1B (As shown) and extending together, the number of magnetically conductive layers 21b is at least 10, or at least 25, or at least 50, or at least 75, or at least 100, or at least 150, or at least 200, or at least 250, or at least 300, or at least 350, or at least 400, and they are bonded together and along the height direction (e.g., Figure 1B Stacked in the z-direction.

[0050] In some embodiments, the generally planar first coil portion 10 is disposed substantially in a reference plane and includes a plurality of substantially concentric first coil loops 10a, 10b, the plurality of substantially concentric first coil loops having an innermost first coil loop 10a and an outermost first coil loop 10b. In some embodiments, each of the first coil loops 10a, 10b may include a plurality of elongated first layers 11 (see...). Figure 1CThe plurality of elongated first layers extend and extend along the azimuth direction 30 and are stacked along the radial direction 31. In some embodiments, the plurality of elongated first layers 11 include at least one conductive first layer 11a and at least one adhesive first layer 11d. In some embodiments, the plurality of elongated first layers 11 of each of the first coil rings 10a, 10b may further include at least one magnetically conductive first layer 11b. In some embodiments, the plurality of elongated first layers 11 of each of the first coil rings 10a, 10b may further include at least one non-adhesive electrically insulating first layer 11c.

[0051] In some embodiments, the generally planar first coil portion 10 includes a first multilayer film 12 (see...). Figure 2D The first multilayer film extends between opposing first longitudinal ends 12a and second longitudinal ends 12b of the first multilayer film 12 and is wound to form a plurality of substantially concentric first coil loops 10a, 10b. In some embodiments, one of the innermost and outermost first coil loops (e.g., 10a) includes the first longitudinal end 12a of the first multilayer film 12, and the other of the innermost and outermost first coil loops (e.g., 10b) includes the second longitudinal end 12b of the first multilayer film 12. In some embodiments, the first longitudinal ends 12a and second longitudinal ends 12b of the first multilayer film 12 may be electrically connected to corresponding first conductive terminals 13a and second conductive terminals 13b.

[0052] In some embodiments, the generally planar core portion 20 may be disposed substantially in a reference plane and at least partially disposed in an opening 14 defined by the innermost first coil loop 10a of the first coil portion 10.

[0053] In some embodiments, the planar core portion 20 may include, for example: Figure 1A The plurality of second layers 20a to 20d stacked along the radial direction 31, or the planar core portion 21 shown. Figure 1B ) can include along the height direction (e.g., along Figure 1B The plurality of second layers 21a to 21d are stacked in the z-direction. In some embodiments, the plurality of second layers 20a to 20d, 21a to 21d may include at least one magnetically conductive second layer 20b, 21b and at least one adhesive second layer 20d, 21d. In some embodiments, the plurality of second layers 20b, 21b may also include at least one conductive second layer 20a, 21a. In some embodiments, the plurality of second layers 20b, 21b may also include at least one non-adhesive, electrically insulating second layer 20c, 21c.

[0054] In some embodiments, the generally planar coil portion 10 and the generally planar core portion 20 may be at least partially embedded in an electrically insulating and non-magnetic substrate 40. In some such embodiments, the substrate 40 may include a flame retardant 4 (FR4) substrate. In some embodiments, the generally planar transformer 300 may also include at least one grounding layer 50, 51 embedded in the substrate 40. In some embodiments, the term "non-magnetic substrate" refers to a substrate with a permeability of 1.

[0055] In some embodiments, the generally planar transformer 300 may further include a generally planar second coil portion 60 (e.g., a secondary coil) substantially disposed in a reference plane and including a plurality of substantially concentric second coil loops 60a, 60b having an innermost second coil loop 60a and an outermost second coil loop 60b. In some embodiments, each of the second coil loops 60a, 60b may include a plurality of elongated third layers 11 (see...). Figure 1C and Figure 2C The plurality of elongated third layers extend and extend along the azimuth direction 30 and are stacked along the radial direction 31. In some embodiments, the plurality of elongated third layers 11 may include at least one conductive third layer 11a and at least one adhesive third layer 11d. In some embodiments, the plurality of elongated first layers 11 of each of the second coil rings 60a, 60b may also include at least one magnetically conductive first layer 11b. In some embodiments, the plurality of elongated first layers 11 of each of the second coil rings 60a, 60b may also include at least one non-adhesive electrically insulating first layer 11c. In some embodiments, the generally planar core portion 20 may be at least partially disposed in the opening 61 defined by the innermost second coil ring 60a of the second coil portion 60.

[0056] In some embodiments, the generally planar second coil portion 60 may include a second multilayer film 12 (see...). Figure 2D The second multilayer film extends between opposing first longitudinal ends 64a and second longitudinal ends 64b of the second multilayer film 12 and is wound to form a plurality of substantially concentric second loops 60a, 60b, wherein one of the innermost second loop 60a and the outermost second loop 60b (e.g., 60a) includes the first longitudinal end 64a of the second multilayer film 12, and the other of the innermost second loop 60a and the outermost second loop 60b (e.g., 60b) includes the second longitudinal end 64b of the second multilayer film 12. In some embodiments, the first longitudinal ends 64a and 64b of the second multilayer film 12 may be electrically connected to corresponding third conductive terminals 62a and fourth conductive terminals 62b.

[0057] In some embodiments, the generally planar transformer 300 may further include a generally planar third coil portion 70, which includes an elongated third multilayer film 12 along its length L1 (see [reference]). Figure 2D The elongated third multilayer film 12 extends between its opposing first longitudinal ends 71a and second longitudinal ends 71b, and is wound in the azimuth direction 30 to form a plurality of substantially concentric third coil loops 70a, 70b, which are arranged in the radial direction 31 and have an innermost third coil loop 70a including the first longitudinal end 71a of the third multilayer film 12 and an outermost third coil loop 70b including the second longitudinal end 71b of the third multilayer film 12. In some embodiments, the elongated third multilayer film 12c may include a plurality of elongated third layers 11 (see...). Figure 2C The plurality of elongated third layers have at least one magnetically conductive third layer 11a and at least one adhesive third layer 11d. In some embodiments, the generally planar first coil portion 10 and the generally planar core portion 20 are at least partially disposed in an opening 73 defined by the innermost third coil loop 70a of the generally planar third coil portion 70.

[0058] In some embodiments, the average height H1 of the generally planar core portion 20 along the height direction (e.g., the z-axis) (see...) Figure 1A The core may be less than about 10 mm, or less than about 9 mm, or less than about 8 mm, or less than about 7 mm, or less than about 6 mm, or less than about 5 mm, or less than about 4 mm, or less than about 3 mm, or less than about 2 mm, or less than about 1 mm. In some embodiments, the core may have an average height H1 in the height direction and a maximum lateral dimension D1 (see [reference]). Figure 2A ), such that the ratio of D1 / H1 is greater than or equal to about 2, or about 3, or about 4, or about 5, or about 10, or about 15, or about 20.

[0059] Continue viewing Figure 2A The maximum lateral dimension D1 of the generally planar core portion 20 can be less than about 50 mm, or less than about 45 mm, or less than about 40 mm, or less than about 35 mm, or less than about 30 mm, or less than about 25 mm, or less than about 20 mm, or less than about 15 mm, or less than about 10 mm.

[0060] In some embodiments, the maximum lateral dimension D2 of the generally planar first coil portion 10 (or the generally planar second coil portion 60, if appropriate) may be less than about 50 mm, or less than about 45 mm, or less than about 40 mm, or less than about 35 mm, or less than about 30 mm, or less than about 25 mm, or less than about 20 mm, or less than about 15 mm, or less than about 10 mm.

[0061] In some embodiments, the maximum lateral dimension D3 of the generally planar third coil portion 70 may be less than about 200 mm, less than about 175 mm, less than about 150 mm, or less than about 125 mm, or less than about 100 mm, or less than about 75 mm, or less than about 50 mm, or less than about 45 mm, or less than about 40 mm, or less than about 35 mm, or less than about 30 mm.

[0062] Check Figure 2B As seen from the top plan view, the generally planar core portion 20 can have any suitable shape, including but not limited to square, ellipse, rectangle, circle (including disk, toroidal, donut, elliptical, coil or other suitable shape). In some embodiments, the generally planar core portion 20 may define a central opening (e.g., a through opening) 22 extending across the entire thickness of the core portion 20.

[0063] Figure 2C and Figure 2D An example of an elongated third multilayer film 12 is shown, and it is discussed in detail elsewhere in this document.

[0064] Figures 3A to 3B The image shows a generally planar core portion 20 with a magnetically conductive second layer (such as a magnetically conductive second layer 20b), which has been intentionally fractured to form cracks that define the magnetically conductive islands. Figure 3A A perspective image of a core (or core portion) 20 with a generally flat surface having a central through opening 22 is shown. Figure 3B This is a close-up image of the magnetically conductive second layer 20b (of the generally planar core portion 20), which has been intentionally broken across substantially the entire second layer 20b to form multiple interconnected cracks 80 defining multiple magnetically conductive islands 81.

[0065] Figures 4A to 4B This illustrates how the surface of a magnetically conductive core, according to this specification, can include a regular pattern of parallel features. Figure 4AThis is an example of a magnetically conductive core 21 comprising multiple second layers 21a to 21d and having opposing top main surfaces 23a and bottom main surfaces 23b. In some embodiments, at least one of the opposing top main surfaces 23a and bottom main surfaces 23b may include a regular pattern 25 comprising a plurality of substantially parallel features 24 across the main surfaces (see, for example...). Figure 4B (Image of the top main surface 23a). In some embodiments, at least one of the features 24 is a groove. For clarity, in Figure 4B The dashed lines are shown to highlight some of the parallel features in parallel feature 24.

[0066] Figure 5 An example is illustrated of a method for manufacturing a magnetically conductive core for use in a transformer, such as an embodiment of the magnetically conductive core 20 discussed elsewhere herein. In some embodiments, the method may include providing a multilayer film 12 (see also...). Figure 2C and Figure 2D The multilayer film 12 comprises at least a plurality of alternating magnetically conductive alloy layers 21b and adhesive layers 21d; the multilayer film 12 is wound around a longitudinal axis 16 to form a wound multilayer film 15. In some embodiments, the wound multilayer film may include a plurality of substantially concentric turns 12n of the multilayer film 12 substantially centered on the longitudinal axis 16; and the wound multilayer film 15 is cut into at least one slice along parallel radial planes P1, P2 to form a core 20. In some embodiments, the cutting step may include one or more of sawing, laser cutting, waterjet cutting, and die cutting.

[0067] In some embodiments, the method of manufacturing the magnetically conductive core may further include intentionally fracturing the magnetically conductive alloy layer 21b over the entirety of these layers to form a plurality of interconnecting cracks 80 defining a plurality of magnetically conductive islands 81 in each of these layers (see, for example...). Figure 3B ).

[0068] at last, Figure 6 Another method for manufacturing a magnetically conductive core for use in a transformer is illustrated, such as an embodiment of the magnetically conductive core 20 discussed elsewhere herein. In some embodiments, the method may include the step of providing a multilayer stack 90, the multilayer stack comprising elements along a first direction (e.g., Figure 6 At least a plurality of alternating magnetically conductive alloy layers 21b and adhesive layers 21d stacked along the z-axis (as shown); and along parallel planes V1, V2 orthogonal to the first direction (e.g., along...). Figure 6The multilayer stack is cut into at least one slice in the x-direction to form core 20. In some embodiments, the cutting step may include one or more of sawing, laser cutting, waterjet cutting, and die cutting. In some embodiments, the method may also include intentionally fracturing the magnetically conductive alloy layer 21b over the entirety of the layers before forming the multilayer stack 90, to form a plurality of interconnecting cracks 80 defining a plurality of magnetically conductive islands 81 in each of the layers (see, for example...). Figure 3B ).

[0069] Terms such as “about” will be understood in the context in which they are used and described by those skilled in the art. If it is unclear to those skilled in the art in the context of their use and description of “about” to express quantities of characteristic size, quantity, and physical properties, then “about” will be understood to mean within 10% of the specified value. A quantity given a specified value as “about” can be precisely the specified value. For example, if it is unclear to those skilled in the art in the context of their use and description of this specification, a quantity having a value of about 1 means that the quantity has a value between 0.9 and 1.1, and that the value can be 1.

[0070] The term "substantially" will be understood by those skilled in the art in the context of its use and description herein. If the use of "substantially equal" is unclear to those skilled in the art in the context of its use and description herein, "substantially equal" will refer to approximately as described above. If the use of "substantially parallel" is unclear to those skilled in the art in the context of its use and description herein, "substantially parallel" will refer to being within 30 degrees of parallelism. In some embodiments, directions or surfaces described as substantially parallel to each other may be within 20 degrees or 10 degrees of parallelism, or may be parallel or nominally parallel. If the use of "substantially aligned" is unclear to those skilled in the art in the context of its use and description herein, "substantially aligned" will refer to alignment within 20% of the width of the aligned objects. In some embodiments, objects described as substantially aligned may be aligned within 10% or 5% of the width of the aligned objects.

[0071] All cited references, patents, and patent applications are incorporated herein by reference in their entirety in a consistent manner. In the event of any inconsistency or contradiction between the incorporated references and this application, the information in the foregoing description shall prevail.

[0072] Unless otherwise indicated, the description of elements in the accompanying drawings should be understood to apply equally to corresponding elements in the other drawings. While specific embodiments have been illustrated and described herein, those skilled in the art will recognize that various alternative and / or equivalent embodiments may be used instead of the illustrated and described embodiments without departing from the scope of this disclosure. This application is intended to cover any modifications or variations of the specific embodiments discussed herein. Therefore, this disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. A generally planar transformer, the generally planar transformer being located substantially within a reference plane defining mutually orthogonal azimuth and radial directions, the generally planar transformer comprising: A generally planar first coil portion, the generally planar first coil portion being disposed substantially in the reference plane, and comprising a plurality of substantially concentric first coil loops, the plurality of substantially concentric first coil loops including an innermost first coil loop and an outermost first coil loop, each of the first coil loops comprising a plurality of elongated first layers, the plurality of elongated first layers being elongated and extended along the azimuth direction and stacked along the radial direction, the plurality of elongated first layers comprising at least one conductive first layer and at least one adhesive first layer; and The generally planar core portion is disposed substantially in the reference plane and at least partially disposed in an opening defined by the innermost first coil loop of the first coil portion, and includes a plurality of second layers stacked along one of the radial direction and the height direction orthogonal to the reference plane, the plurality of second layers including at least one magnetically conductive second layer and at least one adhesive second layer.

2. The generally planar transformer of claim 1, wherein the first coil portion of the generally planar structure comprises a first multilayer film extending between opposing first and second longitudinal ends of the first multilayer film and wound to form the plurality of substantially concentric first coil loops, wherein one of the innermost first coil loop and the outermost first coil loop comprises the first longitudinal end of the first multilayer film, and the other of the innermost first coil loop and the outermost first coil loop comprises the second longitudinal end of the first multilayer film.

3. The generally planar transformer according to claim 2, wherein the first longitudinal end and the second longitudinal end of the first multilayer film are electrically connected to corresponding first conductive terminal and second conductive terminal.

4. The generally planar transformer of claim 1, wherein the permeability of any first layer of any of the plurality of extended first layers in each of the first coil loops is substantially less than the permeability of the at least one magnetically conductive second layer of the plurality of second layers.

5. The generally planar transformer of claim 1, wherein the conductivity of any second layer of the plurality of second layers is substantially less than the conductivity of at least one conductive first layer of the plurality of extended first layers of each first coil loop in the first coil loop.

6. The generally planar transformer of claim 1, wherein the plurality of elongated first layers of each of the first coil loops further comprises at least one magnetically conductive first layer.

7. The generally planar transformer of claim 1, wherein the plurality of elongated first layers of each of the first coil loops further comprises at least one non-adhesive, electrically insulating first layer.

8. The generally planar transformer of claim 1, wherein the plurality of second layers further comprises at least one conductive second layer.

9. The generally planar transformer of claim 1, wherein the plurality of second layers further comprises at least one non-adhesive electrically insulating second layer.

10. The generally planar transformer of claim 1, wherein the coil portion and the core portion of the generally planar transformer are at least partially embedded in an electrically insulating and non-magnetic substrate.

11. The generally planar transformer of claim 1, wherein the second layer in the core portion of the generally planar transformer is stacked along the height direction.

12. The generally planar transformer of claim 1, wherein the second layer in the core portion of the generally planar transformer is stacked along the radial direction.

13. The generally planar transformer of claim 1, further comprising a generally planar second coil portion, the generally planar second coil portion being disposed substantially in the reference plane and comprising a plurality of substantially concentric second coil loops, the plurality of substantially concentric second coil loops including an innermost second coil loop and an outermost second coil loop, each of the second coil loops comprising a plurality of elongated third layers, the plurality of elongated third layers being elongated and extended along the azimuth direction and stacked along the radial direction, the plurality of elongated third layers comprising at least one conductive third layer and at least one adhesive third layer.

14. The generally planar transformer of claim 13, wherein the core portion of the generally planar shape is at least partially disposed in an opening defined by the innermost second coil loop of the second coil portion.

15. The generally planar transformer of claim 13, wherein the second coil portion of the generally planar structure comprises a second multilayer film extending between opposing first and second longitudinal ends of the second multilayer film and wound to form the plurality of substantially concentric second coil loops, wherein one of the innermost and outermost second coil loops comprises the first longitudinal end of the second multilayer film, and the other of the innermost and outermost second coil loops comprises the second longitudinal end of the second multilayer film.

16. The generally planar transformer according to claim 1, wherein the at least one magnetically conductive second layer comprises one or more of magnetically conductive ferrite, soft magnetic material, metal, crystalline alloy, nanocrystalline alloy, amorphous alloy and composite material.

17. The generally planar transformer of claim 1, further comprising a generally planar third coil portion comprising an elongated third multilayer film extending along its length between opposing first and second longitudinal ends and wound in the azimuth direction to form a plurality of substantially concentric third coil loops arranged in the radial direction and including an innermost third coil loop and an outermost third coil loop, the innermost third coil loop including the first longitudinal end of the third multilayer film, the outermost third coil loop including the second longitudinal end of the third multilayer film, the elongated third multilayer film including a plurality of elongated third layers including at least one magnetically conductive third layer and at least one adhesive third layer, wherein the generally planar first coil portion and the generally planar core portion are at least partially disposed in an opening defined by the innermost third coil loop of the generally planar third coil portion.

18. A magnetically conductive core for use in a transformer and having an average height H1 in the height direction and a maximum lateral dimension D1, D1 / H1≥2, the magnetically conductive core comprising a plurality of substantially planar and commonly extending magnetically conductive alloy layers, the number of the magnetically conductive alloy layers being at least 50 in total, stacked in the lateral direction and bonded to each other via a plurality of adhesive layers, wherein the magnetically conductive alloy layers are intentionally fractured substantially throughout the layers to form a plurality of magnetically conductive alloy islands isolated from each other by a plurality of interconnecting cracks.

19. The magnetically conductive core according to claim 18, wherein the magnetically conductive core has the shape of a disk, a ring, a donut, an ellipse, or a coil.

20. The magnetically conductive core according to claim 19, wherein the disk-shaped core has at least one central through-hole.

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