A method of manufacturing an inductor core includes controlling a flow of magnetic material and a flow of binder material to a nozzle such that the flow magnetic material merges with the flow of binder material at a focal point of a preheater, preheating the magnetic material and the binder material by energizing the preheater, mixing the magnetic material and the binder material according to a ratio based on a magnetic permeability distribution of the inductor core, and depositing the magnetic material and the binder material on a surface to form the inductor core having three layers with recessed patterns defined between the layers for receiving a coil.

BACKGROUND

The subject matter disclosed herein relates to magnetic components in electronic circuits, and specifically to low-profile inductors.

Typically, the magnetic components of an electronic circuit are the largest components by volume, the tallest components, and the heaviest components. As electronic devices containing these magnetic components (e.g., smartphones, tablets, laptop computers, etc.) shrink in size and weight, volume within these devices and space on circuit boards within the devices are at a premium. Accordingly, techniques for manufacturing inductors with lower heights, lower weights, and custom form factors without sacrificing performance (e.g., inductance or resistance) would be useful in electronic devices.

BRIEF DESCRIPTION

Certain embodiments commensurate in scope with the original claims are summarized below. These embodiments are not intended to limit the scope of the claims, but rather these embodiments are intended only to provide a brief summary of possible forms of the claimed subject matter. Indeed, the claims may encompass a variety of forms that may be similar to or different from the embodiments set forth below.

In one embodiment, a core includes a first layer, a second layer, and a third layer. The first layer has a first surface, a second surface, and a first recessed pattern extending from the second surface of the first layer toward the first surface of the first layer. The second layer has a third surface, a fourth surface, a second recessed pattern extending from the third surface of the second layer toward the fourth surface of the second layer, and a third recessed pattern extending from the fourth surface of the second layer toward the third surface of the second layer. The third layer has a fifth surface, a sixth surface, and a fourth recessed pattern extending from the fifth surface of the third layer toward the sixth surface of the third layer. The second layer is disposed between the first and third layers such that the second surface of the first layer faces the third surface of the second layer and the fourth surface of the second layer faces the fifth surface of the third layer. The first and second recessed patterns correspond to one another and are configured to receive a coil. The first, second, and third layers have non-uniform magnetic permeabilities.

In a second embodiment, a system includes a computing device, a controller, and a preheater. The computing device includes a memory, wherein the memory is configured to store a file that represents a geometry and a magnetic permeability distribution of an inductor core. The controller communicates with the computing device, controls a first flow rate of a magnetic material from a magnetic material supply to a nozzle, and controls a second flow rate of a binder material from a binder material supply to the nozzle. The preheater is configured to preheat the magnetic material and the binder material before the magnetic material and the binder material are deposited on a surface. The magnetic material and the binder material are mixed according to a ratio based at least in part on the file that represents the geometry and the magnetic permeability distribution of the inductor core.

In a third embodiment, a method of manufacturing an inductor core includes controlling a first flow rate of a magnetic material to a nozzle and a second flow rate of a binder material to the nozzle, preheating the magnetic material and the binder material, mixing the magnetic material and the binder material according to a ratio based on a magnetic permeability distribution of the inductor core, and depositing the magnetic material and the binder material on a surface. The inductor core includes a first layer having a first surface, a second surface, and a first recessed pattern extending from the second surface of the first layer toward the first surface of the first layer, a second layer having a third surface, a fourth surface, a second recessed pattern extending from the third surface of the second layer toward the fourth surface of the second layer, and a third recessed pattern extending from the fourth surface of the second layer toward the third surface of the second layer, and a third layer having a fifth surface, a sixth surface, and a fourth recessed pattern extending from the fifth surface of the third layer toward the sixth surface of the third layer, wherein the second layer is disposed between the first layer and the third layer.

DETAILED DESCRIPTION

Electronic devices, such as smart phones, tablet computers, laptop computers, calculators, handheld gaming devices, etc. may include one or more circuit boards, which include various electronic components, such as inductors, capacitors, and resistors. Inductors are relatively larger components by volume and by weight, and are also typically the tallest components on the circuit board, as compared to other components on the circuit board. As these electronic devices shrink in size and become more compact, space within the device housing and space on the one or more circuit boards are limited. An inductor includes a conductive coil or winding, which may be wrapped around a magnetic core. By utilizing additive manufacturing (e.g., three-dimensional printing) technologies, a core may be manufactured with a non-uniform magnetic permeability distribution (e.g., a non-uniform magnetic permeability that varies from location to location within the core). As will be discussed in more detail below, a desired magnetic permeability of the core at a given location may be achieved by varying the ratio of a binder material (e.g., epoxy) and a magnetic material (e.g., magnetic powder, magnetic ink, or some other magnetic material) during manufacture of the core. As a result, inductor cores with desires permeability distributions (e.g., relatively higher permeability toward the edges and relatively lower permeability toward the center) enable inductors with smaller form factors, but without corresponding reductions in performance, enabling a reduction in form factor of the electronic device containing the inductor.

FIG. 1is a schematic of an embodiment of an additive manufacturing or three-dimensional printing system10for manufacturing inductor cores for use in electronic circuits. In the illustrated embodiment, the system10includes a computing device12, which may store a file (e.g., CAD, OBJ, STL, DXF, AMF, etc.) representative of the core design. The computing device12may be in communication with a controller14, which may control material flow rates from a magnetic material supply16(e.g., magnetic powder or magnetic ink) and a binder material supply18(e.g., epoxy) to a nozzle20. As the materials from the magnetic material supply16and the binder material supply18approach the nozzle20, the materials are heated by a preheater22. The materials may then be mixed and deposited onto a surface, such as the XY table24, via a nozzle or like component that may be coupled to the preheater22. Materials from the magnetic material supply16and the binder material supply18may be mixed in ratios corresponding to the desired magnetic permeability or density and deposited on the XY table24in layers, which combine to form the core.

As illustrated, the computing device12includes a processor26and a memory component28. The processor26may analyze data, execute programs, execute instructions, and control the operating parameters of the additive manufacturing system10. The memory component28may be any non-transitory computer readable medium. The memory component28may store data, processor instructions, programs, optimization algorithms, lookup tables, models, and the like, including processor instructions for implementing the present approaches discussed herein.

In some embodiments, the computing device12may include an operator interface30, which may include a display for displaying information to a user, as well as devices for receiving inputs from a user (e.g., keyboard, mouse, track pad, buttons, dials, touch screen, etc.). A file representative of a core design (e.g., CAD, OBJ, STL, DXF, AMF, etc.) may be stored on the memory component28of the computing device12. The file may be representative of the core design in terms of geometry, density, magnetic permeability, and some other quality. In some embodiments, the computing device12may generate the representative file (e.g., via a software program). In other embodiments, the representative file may be generated on another computing device and transferred to the computing device12of the additive manufacturing or three-dimensional printing system10. The computing device12is in communication with the controller14, which controls the material flow rates out of the magnetic material supply16and the binder material supply18(e.g., via valves). For example, the computing device12may receive a desired ratio, or determine the desired ratio based on the representative file. The computing device12or the controller14may then determine the flow rates from the magnetic material supply16and the binder material supply18based on the desired ratios. The computing device12may provide a signal to the controller14indicative of a desired ratio of magnetic material to binder material. The controller14may then send commands to the magnetic material supply16and the binder material supply18to produce magnetic material and binder material at desired flow rates. In some embodiments, the computing device12and the controller14may be included in the same housing. In some embodiments the functions of the computing device12and the controller14may be performed by the same device.

The magnetic material and the binder material may be heated by the preheater22as the respective materials flow from the magnetic material supply16and the binder material supply18to the nozzle20. The preheater22may be any device that may heat the magnetic material and the binder material via conduction, radiation, or convection. For example, the preheater22may be a coil, a light source, a resistive element, laser, etc. The magnetic material and the binder material may be mixed prior to exiting the nozzle20, and the mixed material may be deposited onto the surface (e.g., the XY table24). The mixed material has a ratio of magnetic material to binder material that corresponds to the desired magnetic permeability values at the deposit location. As multiple layers are deposited on the XY table24, a core is formed having the desired magnetic permeability distribution (e.g., higher permeability toward the edges, than toward the center).

In the illustrated embodiment, the additive manufacturing system10is a powder fed directed energy deposition system, in which the magnetic material supply16and the binder material supplies18provide powdered materials to the focal point of the preheater22(e.g., a laser beam), which melts the material mixture. As each layer is completed, the nozzle20and preheater22move vertically upward and begin depositing the next layer. In some embodiments, the deposition of layers may take place in a hermetically sealed chamber filled with an inert or shielding gas. Such techniques may shield the melt pool from atmospheric oxygen for better control of material properties. However, the disclosed techniques may be used with extrusion-type additive manufacturing methods (e.g., fused deposition modeling, fused filament fabrication, robocasting, extrusion deposition, etc.). Additionally, application of the disclosed techniques to other types of additive manufacturing methods (e.g., stereolithography, digital light processing, powder bed printing, inkjet head printing, electron beam melting, selective laser melting, selective heat sintering, selective laser sintering, direct metal laser sintering, laminated object manufacturing, electron beam freeform fabrication, etc.) may be possible.

FIG. 2is an exploded perspective view of one embodiment of a core50produced by the additive manufacturing system10ofFIG. 1. As illustrated, the core50includes a top layer52, a middle layer54, and a bottom layer56. It should be understood, however, that the core50shown inFIG. 2may include a different number of layers. For example, other embodiments of the core50may include a top layer52, a bottom layer56, and 2 or more middle layers54. Similarly, in some embodiments, the core50may include just a top layer52and a bottom layer56. Use of the terms “top layer” and “bottom layer” are used for convenience and not intended to impose an orientation on the core50. For example, the core50may be oriented such that the top layer52and the bottom layer56may be disposed on either side of the core50rather than on the top and the bottom of the core50. Accordingly, in some embodiments, the core50may be rotated 180 degrees from the view shown inFIG. 2such that the top layer52is disposed on the bottom of the core50and the bottom layer56is disposed on the top of the core50.

As shown, the interior surfaces58of the top layer52and the bottom layer56may include a recessed pattern60. The recessed pattern60extends from the interior surface58toward the exterior surface62. In the illustrated embodiment, the recessed pattern60has a spiral pattern and a semi-circular cross-section. However, it should be understood that other pattern shapes and cross sections (e.g., triangular, square, pentagonal, hexagonal, octagonal, or any other shape) may be possible. The recessed pattern60in the top layer52may or may not correspond to the recessed pattern in the bottom layer56. For example, the recessed pattern60in the top layer52may be the same, similar to, or entirely different from the recessed pattern in the bottom layer56.

The middle layer54includes a top surface64and a bottom surface66. As with the top layer52and the bottom layer56, use of the terms “top surface” and “bottom surface” are used for convenience and not intended to impose an orientation on the middle layer54. As illustrated, the top surface64of the middle layer54, which faces the interior surface58of the top layer52, includes a recessed pattern60that has a spiral shape, a semi-circular cross-section, and corresponds to the recessed pattern60in the interior surface58of the top layer52. That is, when the top surface64of the middle layer54and the interior surface58of the top layer52are placed adjacent to each other, the recessed patterns60align to form a spiral-shaped passageway having a circular cross-section. As will be shown and discussed with regard toFIG. 6, when the inductor is assembled, the coil occupies the volume created by the recessed pattern60.

In embodiments with multiple middle layers54, the recessed pattern60in the top surface64of each middle layer54may match a recessed pattern60in the surface that the top surface64faces. For example, if the top surface64of a middle layer54faces the bottom surface66of another middle layer54, the two facing surfaces64,66may have corresponding recessed patterns. Similarly, the bottom surface66of the middle layer54includes a recessed pattern60that corresponds to the recessed pattern60in the interior surface58of the bottom layer56. In embodiments with multiple middle layers54, the recessed pattern60on the bottom surface66of one middle layer54may correspond to the recessed pattern60on the top surface64of another middle layer54, or to the recessed pattern60on the interior surface58of the bottom layer56.

As previously discussed, in the illustrated embodiment, the recessed pattern60has a spiral pattern and a semi-circular cross-section. However, it should be understood that other pattern shapes and cross sections (e.g., triangular, square, pentagonal, hexagonal, octagonal, or any other shape) may be possible. Furthermore, in some embodiments, such as those in which the recessed pattern has a rectangular cross section, the recessed pattern may only be on one surface in a pair of mating surfaces may include a recessed pattern. For example, in some embodiments, the middle layer may include recessed patterns60in the top and bottom surfaces64,66having a rectangular cross section. In such an embodiment, the recessed patterns may be deeper than a height of the coil such that the coil can lie entirely within the recess. In such an embodiment, the interior surfaces58of the top and bottom layers52,56may not include recessed patterns60. That is, the interior surfaces58of the top and bottom layers52,56may be flat surfaces that enclose the recessed patterns60of the middle layer54.

The middle layer54may include one or more through-holes (shown inFIG. 6) connecting the recessed pattern60in the top surface64to the recessed pattern60in the bottom surface66such that a first coil may extend from an entrance68, through the passage formed by the recessed patterns60in the interior surface58of the bottom layer56and the bottom surface66of the middle layer54, and through the middle layer54. The first coil may contact a second coil that extends through the passage formed by the recessed patterns60in the top surface64of the middle layer54and the interior surface58of the top layer52, and out through the exit70. In embodiments having multiple middle layers54, each middle layer may include two through holes. For example, each middle layer54may have a first through-hole out near the edge of the middle layer54and a second through-hole near the center of the middle layer54.

FIG. 3is an exploded perspective view of one embodiment of the core50shown inFIG. 2.FIG. 3is from a different perspective thanFIG. 2such that the interior surface58of the top layer52, the bottom surface66of the middle layer54, and the exterior surface62of the bottom layer56can be seen. As described with regard toFIG. 2, the top layer52includes the recessed pattern60, which extends from the interior surface58of the top layer52toward the exterior surface62of the top layer52. The recessed pattern60corresponds to (e.g., mirrors) the recessed pattern60on the top surface64of the middle layer (shown inFIG. 2) to receive a coil.

Similarly, the middle layer54includes the recessed pattern60, which extends from the bottom surface66of the middle layer54toward the top surface64of the middle layer54. The recessed pattern60corresponds to (e.g., mirrors) the recessed pattern60on the interior surface58of the bottom56layer (shown inFIG. 2) to receive a coil. As illustrated, the recessed patterns60have a semi-circular cross-section and are generally spiral in shape. However, other cross sections and shapes are envisaged.

Though not shown inFIGS. 2 and 3, the exterior surfaces of the top layer52and the bottom layer56may include features, such as bumps or fins, to increase surface area and to aid in heat dissipation (e.g., heat sinks). Examples of such features are shown and described in more detail with regard toFIGS. 7 and 8. Manufacturing the core by additive manufacturing techniques, rather than traditional manufacturing methods, makes the addition of such features simple and cost effective. In some embodiments, the features may be disposed over the entirety of the exterior surfaces62. In other embodiments, the features may only occupy part of the exterior surfaces62. Based on the design of the circuit board on which the inductor will be installed, the features may be disposed in specific locations on the core50in order to give the inductor a form factor that does not interfere with other components on the circuit board.

FIG. 4is a perspective view of one embodiment of a coil100. As discussed with regard toFIG. 2, the coil100may extend through the passageway formed by the recessed patterns60in two facing surfaces (e.g., the interior surface58of the bottom layer56and the bottom surface66of the middle layer54or the top surface64of the middle layer54and the interior surface58of the top layer52). In the illustrated embodiment, the coil100has a circular cross section and a generally spiral shape, corresponding to the recessed patterns60in the various layers52,54,56of the core50. As with the recessed patterns60, other shapes and cross sections (e.g., triangular, square, pentagonal, hexagonal, octagonal, or any other shape) may be possible.

The coil100includes one or more vertical portions102, which extend vertically upward or downward, transverse to the plane of the spiral. In the illustrated embodiment, the coil includes a vertical portion102at either end of the coil100, one vertical portion102toward the exterior of the coil100and one vertical portion102toward the interior of the coil100. However, in some embodiments, the coil100may only include a single vertical portion102(e.g., the vertical portion102toward the interior of the coil100). The vertical portions may extend through through-holes in the various layers52,54,56of the core50to contact other coils100disposed within the core50.

The coil100shown inFIG. 4is a solid metal coil100. The coil100may be printed (e.g., via the additive manufacturing system10shown inFIG. 1, or some other additive manufacturing system), cast, molded, forged, extruded, stamped, machined, some combination thereof, or made by some other manufacturing process. The coil100may be made of copper, silver, gold, aluminum, brass, zinc, nickel, iron, tin, alloys thereof, or any other conductive metal.

In other embodiments, the coil100may be manufactured by printing a scaffold and then plating (e.g., electroplating) the scaffold. The scaffold may or may not be melted away after plating.FIG. 5is a perspective view of an embodiment of a coil100made of a scaffold104and a plated coating106. The scaffold104may be made of a plastic, such as polyester (PES), polyethylene terephthalate (PET), polyethylene (PE), high-density polyethylene (HDPE), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), high impact polystyrene (HIPS), polyamide (PA), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyurethane (PU), polyetheretherketone (PEEK), Polytetrafluoroethylene (PTFE), or some other polymer. The scaffold104may be printed (e.g., by additive manufacturing), molded, extruded, or manufactured by some other method.

The scaffold104may then be electroplated to form the plated coating106on the scaffold104. The plated coating106may be copper, silver, gold, tin, zinc, chromium, nickel, platinum, lead, a combination thereof, alloys thereof, or some other conductive metal. In some embodiments, the coil100may be heated to melt the scaffold104, leaving just the plated coating106. In other embodiments, the coil100may be used with the scaffold104and the plated coating106.

FIG. 6is a perspective view of an embodiment of the inductor200including the core50shown inFIG. 2and two coils100shown inFIGS. 4 and 5. As shown and described with regard toFIG. 2, the core50includes a top layer52, a middle layer54, and a bottom layer56. The layers52,54,56may be manufactured by additive manufacturing to have a desired magnetic permeability distribution according to the techniques described herein (e.g., comparatively high permeability toward the edges, and reduces magnetic permeability toward the center). As previously described, embodiments of the inductor200are envisaged in which the core has multiple middle layers54. The various layers52,54,56may be bonded to one another or coupled to one another using an adhesive. The corresponding recessed patterns in surfaces of the various layers52,54,56that face one another are form passages. The passages are linked to one another by through holes through the various layers52,54,56, forming a continuous passage204from the entrance68to the exit70. One or more coils100may be disposed within the continuous passage204. In the illustrated embodiment, the inductor200may have a height206of less than 1 millimeter. However, embodiments having other heights are possible.

The various components of the inductor200may be designed using a computer aided drafting (CAD) program. Performance of the inductor may be simulated with using a finite element analysis (FEA) software (e.g., a EM 3d simulation tool). Based on the results of the FEA, the design may be iteratively improved and optimized to achieve the desired (e.g., uniform or distributed) flux density. Once the design is finalized, the various components of the inductor200may be manufactured and assembled. The inductor200may then be installed on a printed circuit board (PCB), or otherwise installed in a device. Though presently disclosed embodiments relate to inductors200, it should be understood that the disclosed techniques may be applied to other electronic components that utilize magnetics, such as transformers.

As discussed above, the top and/or bottom layer52,56of the core50may include heat dissipation features (e.g., heat sinks) in order to better dissipate heat from the core50.FIGS. 7 and 8show two different embodiments of the core50including heat dissipation features.FIG. 7is an exploded perspective view of an example of the inductor core50having an array hemispherical heat dissipation features250. As shown, the exterior surfaces62of the top and/or bottom layers52,56may include heat dissipation features250(e.g., heat sinks) to aid heat dissipation by increasing surface area.FIG. 8is an exploded perspective view of an example of the inductor core50having cylindrical heat dissipation features250. Though the heat dissipation features250illustrated inFIGS. 7 and 8are hemispherical and cylindrical, receptively, it should be understood that these are merely examples and that various other forms of heat dissipation features250are envisaged. For example, the heat dissipation features250may include fins, rectangles, triangles, or any other shape. Similarly, thoughFIGS. 7 and 8show heat dissipation features250on the exterior surfaces62of both the top and bottom layers52,56, it should be understood that in some embodiments, the heat dissipation features250may be disposed on the exterior surface62of either the top layer52or the bottom layer56, but not both.

FIG. 9is a flow chart of a process300for manufacturing the inductor core shown inFIGS. 2 and 3. The following description of the process300is described as being performed by the computing device12, but it should be noted that any suitable processor-type device (e.g., controller14) may perform the process300. In block302, the computing device12may receive a ratio of magnetic material to binder material at a given location of the core. In one embodiment, the computing device12may receive the ratio of magnetic material to binder material at a given location of the core via a file representative of the core design. The ratio of magnetic material to binder material may represent a desired permeability of the core at a given location. In block304, the computing device12may determine flow rates for the magnetic material and the binder material based, at least in part, on the received ratio of magnetic material to binder material. In block306, the computing device12may generate one or more control signals that represent the respective magnetic material and binder material flow rates over time. The magnetic material and binder material flow rates over time may dictate the ratio of magnetic and binder material at a given location on the core100.

In block308, the computing device12may transmit the control signal representative of the magnetic material and binder material flow rates to the controller14, which may control the operations of the magnetic material and binder material supplies.

In block310, the computing device12may send a command to a nozzle to moved to a desired location (e.g., the location corresponding to the determined ratio of magnetic material to binder material). In block312, the computing device12may send a command to the preheater23to preheat the magnetic material and the binder material as they flow from the magnetic material supply16and the binder material supply18. As such, the magnetic material and the binder material are mixed by the preheater22. In block314, the computing device12may send a command to the nozzle to deposit the mixed magnetic binder material onto a surface (e.g., on the XY table24). The process300may then return to block310by moving the nozzle to a new location. The process300continues until the core has been produced.

Technical effects of the disclosed subject matter include utilizing additive manufacturing techniques to manufacture an inductor core layers having a desired magnetic permeability distribution. When the core layers are assembled with coils disposed between the core layers to form an inductor, the resulting inductor may have a reduced height, volume, and weight, as well as a customizable form factor, without reduced performance (e.g., inductance and/or resistance). Furthermore, the resultant inductor may achieve uniform magnetic flux distribution and the same or increased power density.