This disclosure generally relates to electronic components such as inductors and, more particularly, to the winding configuration and orientation of a conductor around a core, and methods relating to same.
The electronics industry is continually called upon to make products smaller and more powerful. Applications such as mobile phones, portable computers, computer accessories, hand-held electronics, etc., create a large demand for smaller electrical components. These applications further drive technology and promote the research of new areas and ideas with respect to miniaturizing electronics. The technology is often limited due to the inability to make certain components smaller, faster, and more powerful.
Magnetic components, such as inductors, are examples of the type of components that have been forced to become smaller and/or more powerful. Typical inductors often comprise a wire wound or coiled about a core of magnetic material, such as ferrite, with the ends of the wire forming respective terminals for mounting the component into an electronic circuit of some type, usually on a printed circuit board. The core and the coil each occupy substantial space both in height and surface footprint. Typically, as the induction and power handling of an inductor increases or otherwise improves, the footprint and/or the height of the inductor also increases, often beyond the allowable space allocated for such an inductor within the form factor of an electronic device utilizing the inductor. However, as electronic devices, such as mobile telephones, smart phones, PDAs, and other portable electronic devices, become smaller, less space is allowed for such inductors while at the same time the performance required by such inductors often increases.
Accordingly, it has been determined that the need exists for an improved inductor component and method for manufacturing the same which overcomes the aforementioned limitations, and which further provide capabilities, features and functions, not available in current devices and methods for manufacturing.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will also be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein.
Generally speaking, pursuant to these various embodiments, an electronic component, such as an inductor, comprises a core having a conductor wound around at least a portion of the core to form at least a partial turn/winding, or a number of turns/windings. The core may be elongate and extend horizontally or parallel to the surface to which the electronic component is mounted. The electronic component may further include terminals connected to or formed by the each of the ends of the conductor for electrically coupling the electronic component into at least one circuit (e.g., a printed circuit board).
Referring now to the drawings, and in particular
The component 100 may further include two terminals, a first terminal 130 and a second terminal 140. In the embodiment shown, the first terminal 130 and the second terminal 140 are formed by the end portions of the conductor 150. In other embodiments, the first terminal 130 and second terminal 140 may be clips to which the ends of the conductor 150 are electrically coupled. For example, a clip may be mounted to the side of the component 100 in electrical contact with an end portion of the conductor. The clip may have a conductive plate that provides a surface that can be soldered to in order to mount the component, e.g., to a circuit board. The first terminal 130 and second terminal 140 are configured for mounting and mechanically coupling the electronic component 100 to a mounting surface, such as a surface of a circuit board, and to electrically couple the electronic component to a circuit. The first terminal 130 and the second terminal 140 may be flush with a bottom surface 135 of the electronic component 100 or extend within a plane that is substantially parallel to the mounting or bottom surface 135 of the electronic component 100. The terminals 130, 140 may thus extend within a plane for mounting the electronic component 100 to a substantially flat mounting surface that is substantially parallel to bottom surface of the electronic component 100 and/or plane in which the terminals 130, 140 extend.
As shown, the core 110 is substantially cylindrical and elongated, defining an axis of the core 110. In other forms, the core 110 may have other configurations for example, the core 110 may have a polygonal cross-sectional shape (e.g., pentagonal, hexagonal). The core 110 extends substantially parallel to the bottom surface 135 of the electronic component 100 and/or mounting surface to which the electronic component is to be mounted (e.g., within 30 degrees). One benefit of including a core 110 that extends parallel to the circuit to which the electronic component 100 is mounted is that the height of the electronic component 100 may be minimized. For instance, the length of the core 110 may be increased without increasing the height of the electronic component 100. This may be advantageous in applications where the electronic component 100 must not exceed a certain height, yet the electronic component 100 requires a longer core 110 to achieve the desired performance specifications. For example, it allows a more powerful component to be provided in situations where height constraints are rigid by simply allowing for a longer core to be used so that a conductive coil with more turns may be provided, all while sticking within the height requirements. Obviously, this leads to a larger footprint being taken-up on the circuit board, so it will not be appropriate for all applications. Regardless, the horizontal orientation of the core (or generally parallel to the printed circuit board (PCB)) allows for a variety of windings to be used as the conductor (e.g., different lengths of wire, different sized of wire, differing number of turns of the wire wound coil, etc.). In a preferred form, the core will extend out beyond the conductor (or wire wound coil or winding) on each open-end of the coil to improve the performance of the component because the core contains more dense material than the outer mixture making up the outer body of the component which creates a more open magnetic field so current rating goes up or increases because the component simulates an open structure like a solenoid. In a preferred form, the core will only extend out beyond the open ends of the coil in an amount that is between (a) a smaller distance that is a little less than the width of the wire wound coil or coil winding and (b) a larger distance that is a little greater than the width of the coil winding.
In the embodiment shown in
The conductor 150 may be a wire or other conductive component. The conductor 150 extends from a first end forming the first terminal 130 to a second end forming the second terminal 140 with the winding 160 formed on a portion of the conductor 150 therebetween. The first terminal 130 may be formed by bending the first end of the conductor 150 at bend 130A to extend substantially parallel to the bottom surface 135 of the electronic component 100 and/or mounting surface. The second terminal 140 likewise may be formed by bending the second end of the conductor 150 at bend 140A to extend substantially parallel to the bottom surface 135 of the electronic component 100 and/or mounting surface The wire of the conductor 150 may be a flat wire and have a thickness in the range of about 0.2 mm to about 0.6 mm, although a number of other shapes and thicknesses of the wire for the conductor 150 may be used. In one specific example, the wire has a thickness of about 0.4 mm. The conductor 150 may have a rectangular cross-section having wide opposing sides spaced apart by narrow opposing edges. In another example, the wire of the conductor 150 is a square wire having a substantially square cross-section. In yet other forms, the wire of the conductor 150 is a round wire having a substantially circular cross-section.
The winding 160 of the conductor 150 extends around more than 50% of the outer surface or circumference of the core 110. In one specific example, the winding 160 of conductor 150 extends around about 70% of the outer surface or circumference of the core before extending tangentially from the core 110 to the terminals 130, 140 (which again the terminals may be formed in a self-leaded fashion meaning from the winding itself and not necessarily a separate structure if desired). As shown in
In the embodiment shown in
Turning now to
Similar to the electronic component 100 of the first embodiment, the electronic component 200 includes an elongate core 210 and a conductor 250 having a winding 260 positioned about the core 210. The axis of the core 210 and the axis of the winding 260 extend horizontally or substantially parallel to a bottom surface 235 of the electronic component 200 and/or a mounting surface to which the first terminal 230 and the second terminal 240 are configured to be mounted to. A primary difference of the electronic component 200 of the second embodiment 200 is that the winding 260 of the conductor 250 is wound helically along an axis. In the embodiment shown, the winding 260 includes 1.5 turns. The turns of the winding 260 extend helically along the outer surface of the core 210 from the first terminal 230 to the second terminal 240. As with the first embodiment, the conductor 250 may be a flat wire having a thickness in the range of about 0.2 mm to about 0.6 mm, although a number of other shapes and thicknesses may be used. The conductor 250 may have a rectangular cross-section having wide opposing side-faces spaced apart by narrow opposing edge-faces. In another example, the wire of the conductor 250 is a square wire having a substantially square cross-section. In yet other forms, the wire of the conductor 250 is a round wire having a substantially circular cross-section.
The conductor 250 may be wound about the core 250 in an edge-face to edge-face configuration with a wide opposing side-face of the winding 260 of the conductor 250 facing inward toward the core 250. The performance characteristics of the component (or parameters) depend largely on the size of the component (e.g., large size allows for larger conductors to be used, more turns, etc.). In a preferred form, the component will provide an inductance range between 20 nH-1.5 μH. In one form a 3 mm2 outer body size will be used with a single turn conductor yielding a 56 nH-330 nH inductance range. As will be discussed further herein, a two-turn conductor configuration may be provided that yields a little better than a 56 nH inductance, a three-turn conductor configuration may be provided that yields a 100 nH inductance, a four-turn conductor configuration may be provided that yields a 200 nH inductance, and a five-turn configuration may be provided that yields a 330 nH inductance.
The component 200 may include an outer body 220 disposed about at least a portion of the core 210 and the conductor 250. The first terminal 230 may be formed by a bend 230A in the conductor 250 at the first end of the winding 260 and the second terminal 240 may be formed by a bend 240A at the second end of the winding 260. The bottom surfaces 232, 242 of the first terminal 230 and the second terminal 240 of the conductor 250 extend substantially parallel to or within the same plane as the bottom surface 235 of the electronic component 200 such that the terminals 230, 240 extend parallel to the mounting surface to which the electronic component 200 is to be mounted. As with the first embodiment, the bottom surfaces 232, 242 and/or the end faces 234, 244 of the terminals 230, 240 may remain exposed through the outer body 220 for electrically coupling the electronic component 200 to a circuit. In some forms, the ends of the core 210 may remain exposed or extend through the outer body 220 whereas in other forms the ends of the core 210 may be covered by the outer body 220.
Additionally or alternatively, in some forms, the side faces 270, 272 of the conductor 250 remain exposed through the outer body 220 for electrically coupling the electronic component to a circuit at the sides of the electronic component 200. For example, the side faces 270, 272 may be exposed through the outer body 250 as they extend along the bottom of the electronic component 200 from the bends 230A, 240A to the end faces 234, 244. Exposing the side faces provides an alternative or additional surface to which the electronic component 200 may be soldered to a mounting surface.
In some forms, clips or conductive plates may be mounted to the sides of the electronic component 200 and electrically coupled to the ends of the windings to form a solderable surface for mounting the electronic component to a mounting surface. For example, a first conductive plate may be in electrical contact with and extend along at least a portion of the side faces 270 to form terminal 230 and a second conductive plate may be in electrical contact with and extend along at least a portion of the side face 272 to form terminal 240.
With reference to
In the embodiment shown in
With reference to
With reference to
In other embodiments, a conductor may be wound to include six or more windings. The conductor may be positioned about a core similar to the previously described embodiments. In some forms, the conductor may have a smaller wire size (e.g., width and/or thickness) for each additional winding. For example, the size of the wire may be decreased such that the overall axial length of the winding of the conductor, and thus the overall size of the electronic component, does not increase with the increase in additional turns. This may permit an electronic component to have additional turns to achieve different performance specifications while maintaining the footprint of the electronic component on a circuit board.
In each of the above-described embodiments, the core 110 and the conductor 150 comprise an assembly. While the following discussion refers to the electronic component 100 of the first embodiment, it should be understood that the following discussion also applies to each of the above-described embodiments is not limited to only the first embodiment. The conductor 150 may be wound to form the winding 160. In some forms, the conductor 150 is wound about the core 110. In other forms, the conductor is wound about an axis and the core 110 is positioned within the winding 160. Once assembled, the assembly is encased or embedded in the outer body 120. By one approach, the outer body 120 comprises a mixture of magnetic and/or non-magnetic powder that can be potted and cured, injection molded (which includes transfer molded or wet-press compression molded as discussed herein), or dry-press compression molded. For example, in one embodiment, the mixture that makes up outer body 120 includes a powdered iron or iron alloy, such as Carbonyl Iron powder, and a polymer binder, such as a plastic solution, which are compression molded over the core 110 and the conductor 150. In a preferred form, the ratio of powdered iron or iron alloy to binder is about 10% to 98% powdered iron or iron alloy to about 2% to 90% binder, by weight. In the embodiments illustrated, the ratio of powdered iron to binder will be about 80% to 92% powder iron or iron alloy to about 8% to 20% polymer resin, by weight. As with the compression molded component, the potted component may alternatively use powdered ferrite or a mixture of powdered ferrite and another powdered iron or iron alloy. In other forms, other types of powdered iron or iron alloys may be used and/or composite materials may be used, if desired. Some common materials used for the powdered iron include amorphous alloy powders, carbonyl iron powder, nylon coated barium ferrite powders, barium ferrite powders, iron powders, steel powders (e.g., Anchor, Ancormet, Ancorsteel), magnetic ceramic powders (e.g., Ceramag), as well as other equivalent materials and mixtures. In some forms, materials may be at least one material selected from the group consisting of carbonyl iron powders, ferrite powders, barium ferrite powders, iron powders, steel powders, permalloy powder, sendust powder, magnetic ceramic powders, iron alloys, as well as mixtures thereof. The binder may be any conventional binder, e.g., any epoxy binders including epoxy powder, phenol (phenolic) resins, silicone resins, acrylic resins, or other binders, such as hot melt adhesives of one or more materials from the group comprising thermoplastic resins, thermosetting resins (thermal set), polyvinyl alcohol (PVA) binder, polyvinyl butyral (PVB) binder, hot melt adhesives, or other similar binders as well as mixtures thereof.
It is possible and even desirable in some low current, high inductance applications for the molded mixture of the outer body 120 to further include powdered ferrite and, depending on the application, the powdered ferrite may actually replace the powdered iron in its entirety. For example, a ferrite powder with a higher permeability may be added to the mixture to further improve the performance of the component 100. The above ratios of powdered iron are also applicable when a combination of ferrite and powdered iron is used in the mixture and when powdered ferrite is used alone in the mixture. In yet other embodiments, other types of powdered metals may be used in addition to or in place of those materials discussed above.
After compression molding the mixture, the mold may be removed from a molding machine and the component 100 may be ground to the desired size (if needed). The component 100 is then removed from the mold and stored in conventional tape and reel packaging or other conventional packaging for use with existing pick-and-place machines in industry. A lubricant such as Teflon or zinc stearate may also be used in connection with the mold in order to make it easier to remove the component 100, if desired.
Alternatively, the component 100 may be made by potting and curing the mixture that makes up the outer body 120, rather than compression molding the component 100. The main advantages to potting and curing are that the component 100 can be manufactured quicker and cheaper than the above-described compression molding process will allow. In this embodiment, the mixture that makes up outer body 120 may similarly be made of magnetic and/or non-magnetic material and will preferably include a powdered iron, such as Carbonyl Iron powder, and a binder, such as epoxy, which is potted and cured over the core 110 and conductor 150. In this embodiment, the ratio of powdered iron or iron alloy to binder is about 10% to 98% powdered iron or iron alloy to 2% to 90% binder, by weight, with a preferred ratio of powdered iron or iron alloy to binder being about 70% to 90% powder iron or iron alloy to about 10% to 30% epoxy, by weight. As with the compression molded component 100, the potted component 100 may alternatively use powdered ferrite or a mixture of powdered ferrite and another powdered iron. In other forms, other types of powdered iron or iron alloys may be used and/or composite materials may be used, if desired. Regardless of whether the component is potted and cured, injection molded (including for example transfer molding or wet compression molding of a liquid or slurry of mixtures), or dry compression molded, the ratio of binder (e.g., epoxy, resin, etc.) to magnetic and/or non-magnetic material (e.g., powdered iron, powdered ferrite, etc.) impacts the inductance and current handling capabilities of the electronic component.
In this configuration, the assembled core 110 and conductor 150 will preferably be inserted into a recess that contains the mixture making up the outer body 120 and an adhesive such as glue. The mixture and assembly are then cured to produce a finished component 100. As with the first embodiment discussed above, the cured component 100 may also be ground to a specific size (if desired) and then packaged into convention tape and reel packaging for use with existing pick-and-place equipment.
Regardless of whether the component 100 is potted and cured, injection molded (which may include transfer molded or wet-press compression molded using a liquified or slurry mixture to inject about the core and conductor), or dry-press compression molded, the ratio of binder (e.g., epoxy, resin, etc.) to magnetic and/or non-magnetic material (e.g., powdered iron, powdered ferrite, etc.) impacts the inductance and current handling capabilities of the electronic component 100. For example, increasing the amount of epoxy or resin and lowering the amount of powdered iron produces a component 100 capable of handling higher current but having lower inductance capabilities. Therefore, changing the ratio of the substances relative to one another produces different components 100 with different capabilities and weaknesses. Such options allow the component 100 to be customized for specific applications. More particularly, customizing the electronic component 100 allows the component 100 to be precisely tailored to the particular chosen application. Different applications have different requirements such as component size, inductance capabilities, current capacity, limits on cost, etc. Customization can include choosing a wire gauge and length relative to the amount of current and/or inductance required for the application. For example, higher inductance applications may require an increased number of coil turns, and/or a wire with a relatively large cross-sectional area (i.e., gauge).
In addition, customization can include selecting the material that comprises the core 110, along with the dimensions, and structural specifications for the core 110. For example, a ferrite with higher permeability or higher dielectric constants may be chosen to increase inductance. By varying the ratio of elements that comprise the ferrite the grade of the ferrite changes and different grades are suited for different applications.
While many of these variables can alter various specifications of the electronic components, many of them can also create constraints on other variables. For example, increasing the number of turns of the conductor 150, as shown in the embodiments above, may limit the size of the core 110 that can be used if a specific component length must be reached. Similarly, increasing the number of turns of the conductor 150 may limit the size of the wire that may be used to achieve an electronic component having desired dimensions and performance capabilities. Therefore, application requirements and material limitations must be considered when choosing the core 110 material and other specifications.
In addition to choosing the core 110, the components of the mixture that makes up outer body 120 must also be selected. The mixture typically includes a powder metal iron such as ferrite or Carbonyl Iron powder and either resin or epoxy. The application and manufacturing constraints determine which components to include in the mixture. In low current, high inductance applications, it may be more desirable to increase the percentage of ferrite used in the mixture making up body 120. Conversely, in high current, low inductance applications, it may be more desirable to limit the percentage of ferrite (if any) used in the mixture making up body 120.
It is well known in the art to use a dry mold or dry press process to form a magnetic mixture around a wire coil, thereby creating a green body which can be further heated (i.e., a secondary heating) to form the electrical component 100. Such processes often require significant forces that can damage or destroy certain types, configurations, or gauges of wire. An electrical component 100 that has been damaged via such processes may short or otherwise fail. Further, the type and extent of damage that may occur during such processes can vary depending on the placement, direction, or magnitude of the compression forces involved, making this problem difficult to detect and address, and possibly resulting it some components 100 passing internal tests only to fail after shipment.
In order to avoid such shortcomings, the core 110 may be used to help retain and/or protect the configuration of the conductor 150 and help it withstand the various forces and pressures it may be subjected to during manufacture. Furthermore, instead of employing a dry press process to mold the mixture around the wire, the mixture making up outer body 120 may be heated to a liquid that can then be dispersed (e.g., injected or disposed) over at least a portion of the conductor 150 to avoid exposing the conductor 150 to the damaging forces of a dry press process. For example, in one form, the mixture may be liquefied and dispersed over the conductor 150 and the core 110 via an injection molding, compression molding or other molding process, and then hardened to form outer body 120. After the liquid mixture has been formed into the outer body 120, the component 100 may be removed from the mold.
By a further embodiment, the outer body 120 may be a pre-formed cap or case that may be composed of any of the various combinations of materials discussed above or may be composed of formed sheet metal or cast metal, such as aluminum, steel, copper, or the like. The pre-formed outer body 120 is then attached to the first terminal 130 and second terminal 140 and/or the ends of the core 110 by conventional means to form an encased, or overmolded, component 100.
By a further embodiment, the outer body 120 may be a pre-formed cap or case that may be composed of any of the various combinations of materials discussed above or may be composed of formed sheet metal or cast metal, such as aluminum, steel, copper, or the like. The pre-formed outer body 120 is then attached to the first terminal 130 and second terminal 140 by conventional means with the ends of the core 110 exposed at each end of the component 100.
By creating an inductor according to these teachings, the inductor is well suited for use in power applications, such as battery power application, and more particularly in applications where the input is higher than the output. The component is suitable for use for any magnetic applications (e.g., transformer, inductors, etc.), but preferably will be used in any number of inductor applications (e.g., power inductors, chokes, RF applications, filters, DC-DC converters, etc.).
Although a flat wire embodiment is described throughout this disclosure, other wire forms may be suitable for use in the electronic component 100, including standard round wire, thin films, or other conductors. For example, these teachings can readily be utilized with eighteen gauge to forty-two gauge (18 AWG-42 AWG) round or flat wire, though wire of larger or smaller gauges can be utilized equally as well dependent upon the specifics of the application. In a preferred form, the range will be 28 AWG-42 AWG). In practice, the specific application and height of the component 100 will often factor into what wire gauge is selected. Similarly, as the preferred later embodiments (e.g.,
Furthermore, those skilled in the art will recognize that a wide variety of modifications, alterations, and combinations can be made with respect to the above-described embodiments without departing from the scope of the invention, and that such modifications, alterations, and combinations are to be viewed as being within the ambit of the inventive concept.
This application claims the benefit of U.S. Provisional Application No. 63/299,525, filed Jan. 14, 2022, and is incorporated herein by reference in its entirety.
Number | Date | Country | |
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63299525 | Jan 2022 | US |