OPTIMIZED ELECTROMAGNETIC INDUCTOR COMPONENT DESIGN AND METHODS INCLUDING IMPROVED CONDUCTIVITY COMPOSITE CONDUCTOR MATERIAL
Electromagnetic inductor components include a magnetic core and a conductor assembled with the core and defining a winding completing a number of turns. The conductor is fabricated from a composite material including carbon nanotubes having an improved conductivity. The conductor has a cross section defined by an effective diameter. The conductor is fabricated to have performance parameters that are selected in view of a function of a ratio of conductivity and/or a function of a ratio of effective diameter of the composite conductor material relative to a reference conductor material as conventionally used in an inductor fabrication.
The field of the invention relates generally to the design manufacture of electromagnetic components and related methods, and more particularly to the design and manufacture of electromagnetic components such as inductors for electronic devices and applications.
Electromagnetic components such as inductors are known that utilize electric current and magnetic fields to provide a desired effect in an electrical circuit. Current flow through a conductor in the inductor component generates a magnetic field. The magnetic field can, in turn, be productively used to store energy in a magnetic core, release energy from the magnetic core, or to cancel undesirable signal components and noise in power lines and signal lines of electrical and electronic devices.
Recent trends to produce increasingly powerful, yet smaller electronic devices have led to numerous challenges to the electronics industry. Electronic devices such as smart phones, personal digital assistant (PDA) devices, entertainment devices, and portable computer devices, to name a few, are now widely owned and operated by a large, and growing, population of users. Such devices include an impressive, and rapidly expanding, array of features allowing such devices to interconnect with a plurality of communication networks, including but not limited to the Internet, as well as other electronic devices. Rapid information exchange using wireless communication platforms is possible using such devices, and such devices have become very convenient and popular to business and personal users alike.
For surface mount component manufacturers for circuit board applications required by such electronic devices, the challenge has been to provide increasingly miniaturized inductor components so as to minimize the area occupied on a circuit board by the inductor component (sometimes referred to as the component “footprint”) and also its height measured in a direction perpendicular to a plane of the circuit board (sometimes referred to as the component “profile”). By decreasing the footprint and profile of inductor components, the size of the circuit board assemblies for electronic devices can be reduced and/or the component density on the circuit board(s) can be increased, which allows for reductions in size of the electronic device itself or increased capabilities of a device with comparable size. Miniaturizing electronic components in a cost effective manner has introduced a number of practical challenges to electronic component manufacturers in a highly competitive marketplace. Because of the high volume of inductor components needed for electronic devices in great demand, cost reduction in fabricating inductor components has been of great practical interest to electronic component manufacturers.
In order to meet increasing demand for electronic devices, especially hand held devices, each generation of electronic devices need to be not only smaller, but offer increased functional features and capabilities. As a result, the electronic devices must be increasingly powerful devices. For some types of components, such as electromagnetic inductor components that, among other things, may provide energy storage and regulation capabilities, meeting increased power demands while continuing to reduce the size of inductor components that are already quite small, has proven challenging.
Non-limiting and non-exhaustive embodiments are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various drawings unless otherwise specified.
Exemplary embodiments of inventive electromagnetic component assemblies and constructions, and related methodologies and methods of inductor component design and manufacture, are described below that, among other things, facilitate the design and manufacture of optimal electromagnetic inductor components in applications such as power circuitry for higher current and power applications having low profiles that are difficult, if not impossible, to achieve, using conventional electromagnetic component design and fabrication techniques. Electromagnetic inductor components, and more specifically power inductor components, may also be fabricated with reduced cost compared to other known miniaturized inductor component constructions. Manufacturing methodology and steps associated with the devices described are in part apparent and in part specifically described below but are believed to be well within the purview of those in the art without further explanation. While described in the context of power inductors, other types of inductors may likewise benefit from the concepts disclosed herein below, including but not limited to non-power inductors such as noise cancelling inductors.
As used herein the term “power inductor” shall refer to an electromagnetic component provided in power supply management applications and power management circuitry on circuit boards for powering a host of electronic devices, including but not necessarily limited to hand held electronic devices. Power inductors are designed to induce magnetic fields in magnetic cores via current flowing through one or more conductive windings, and store energy via the generation of magnetic fields in magnetic cores associated with the windings. Power inductors also return the stored energy to the associated electrical circuit as the current through the winding and may, for example, provide regulated power from rapidly switching power supplies.
As used herein, the term “non-power inductor,” amongst other things, shall refer to an electromagnetic component provided for filtering purposes in an electrical circuit, and is distinguishable from a power inductor. Such non-power inductors are sometimes referred to as noise suppression components and typically operate on signal lines, as opposed to power lines, in the circuitry. For example, one type of non-power inductor is designed to induce magnetic fields in a magnetic core via current flowing through more than one conductive winding in opposite directions to one another, with the magnetic fields cancelling one another to remove undesirable noise. Unlike a power inductor, a non-power inductor is typically not designed to store energy via the generation of magnetic fields. In a non-power inductor, energy storage would effectively amount to an undesirable, parasitic power loss in the circuitry.
For clarity, the term “transformer” shall refer to an electromagnetic component provided for achieving an increase or decrease in current or voltage in an electrical circuit, and is distinguishable from the inductors described above (i.e., power and non-power inductors). Transformers are designed to induce a magnetic field in a magnetic core as current flows through a primary winding, and from that magnetic field to induce a current in a secondary winding that is configured to have a ratio of the turns of the primary winding. The current output from the secondary winding may be increased or decreased by the ratio provided in the primary and secondary winding. Also unlike a power inductor, a transformer is typically not designed to store energy via the generation of magnetic fields. In a transformer, energy storage would effectively amount to an undesirable, parasitic power loss in the circuitry. Each type of electromagnetic component described above therefore utilizes principles of magnetism and inductance via current flow through electrical conductors, but in different ways to achieve a desired result. The different ways that the principles of inductance and desired results are obtained are reflected by structural differences in the devices that allow such disparate results to occur. As such, one type of electromagnetic inductor component (e.g. a power inductor) is generally incapable of serving as another type (e.g., a non-power inductor). Likewise, neither power inductor components nor non-power inductor components are generally capable of serving as a transformer, nor are transformer components generally capable of serving as power or non-power inductor components. Instead of being interchangeable components, each type of electromagnetic component described above is typically custom designed for a particular application and environment, and even in the same application or environment, power inductors, non-power inductors, and transformers may be provided as discrete components that are used in combination with each component providing its own unique function in the circuitry.
The engineering principles of electromagnetic inductor component design are well known but difficult to apply in some aspects, and as a result the manufacture of electromagnetic inductor components is partly experimental in nature. That is, electromagnetic inductor component manufacturers tend to adopt designs through an iterative process wherein a design may be developed in a theoretical manner, prototypes of the design may be made and tested to evaluate the theoretical design, changes are proposed in view of the test results, and another round of components is made and tested. Such a process may be, and has been, successfully accomplished to provide satisfactory electromagnetic inductor components meeting desired specifications in certain aspects. To some extent, because of the number of inductor designs that are known for certain applications, the theoretical design step may be omitted and one may instead change an existing design and proceed with testing of prototypes to assess the impact of the change.
Because of the experimental nature of the electromagnetic inductor component design, a design may be achieved that meets a specification but is nonetheless sub-optimal. Because the impact of a design change in one aspect of the inductor component manufacture to other aspects of the resultant component are not well understood or easy to predict, there is typically some trial and error in arriving at a final design that meets a specification in a desired attribute, but once the specification is met it may have negatively (and unknowingly) affected another performance attribute. This is perhaps even more so in the manufacture of miniaturized inductor components that may be surface mounted to circuit boards in smaller packages and design envelopes to facilitate the manufacture of increasingly smaller and/or increasingly powerful portable electronic devices.
Any inductor component will include an electrically conductive coil and a magnetic core. The basic, theoretical design of the inductor component may proceed with the application of Ampere's law (relating to the current flow through the coil(s) in the component when connected to an energized electrical circuit), Faraday's law (relating to the generation of magnetic fields created by current flow through the coil(s)) and the particular characteristics of the magnetic core material in which the magnetic fields occur. The coils define a number of turns of a winding to achieve a desired effect, such as, for example, a desired inductance value for a selected end use application of the inductor component. Inductance ratings of the inductor component may be varied considerably for different applications by varying the number of turns in the winding, the arrangement of the turns of the winding in the magnetic core, the cross sectional area of the turns in the winding, and the properties of the magnetic core materials themselves. Physical gaps may be established for the storage of energy in the magnetic core, and/or so-called distributed gap materials may be utilized to construct the core. The core may be constructed in one piece or multiple pieces.
A great focus is reflected in the patent literature regarding the development of magnetic core materials that can enhance the performance of electromagnetic inductor components in various applications, and a great variety of different shapes of the magnetic cores is also reflected in the patent literature to achieve desired inductor characteristics. In some cases, separate core pieces are combined to define a magnetic core structure. In other cases, single piece, monolithic cores structures may be provided to embed, encase or surround portions of the inductor windings. The core pieces may be fabricated from granular, magnetic powder materials in a pressing operation (sometimes referred to as a “dust core” construction). Magnetic core structures may alternatively be laminated using layers of pre-formed materials that are joined or united as layers, or successively formed one upon another in the fabrication of an inductor component. Magnetic core structures may be formed to include a combination of discrete inductor components that are each individually operable, or may be formed to include windings that are mutually coupled to one another in a flux sharing relationship. Single phase and multi-phase inductor components may be provided for different electrical power distribution systems.
Regarding the fabrication of the coils for an inductor component, copper is and has been predominately the conductive material of choice by electromagnetic component manufacturers. A great deal of different configurations of windings now exist that can be combined with the various different magnetic materials discussed above. Coils and windings fabricated from copper have been effectively utilized to provide adequate performance in combination with a variety of magnetic materials to fabricate the magnetic core including the windings in increasingly smaller packages. Great efforts have been made in recent times, with some success, to manufacture smaller electromagnetic inductor components and/or to increase the power capabilities of inductor components that are already quite small.
However, the use of copper to fabricate the inductor windings or coils is believed to impose a ceiling to the development of higher performing inductors and/or to provide comparable performance to existing inductors in smaller package sizes. In other words, the performance potential of copper windings and known magnetic materials is believed to have reached its peak, such that copper-based winding and coils have little more to offer in terms of providing performance improvement and reduction in size of inductor components. Because the demand for further size reduction and miniaturization of inductor components having improved performance has not subsided, a new approach is needed to further improve electromagnetic inductor performance, reduce the size of electromagnetic inductor components, and also to reduce the cost of electromagnetic inductor components.
In order to achieve increased performance while continuing to reduce the size of electromagnetic inductor components that are already quite small, the present invention proposes the use of a composite conductive material for fabricating the coils of the electromagnetic inductor component. In contemplated examples, the composite conductive material has a conductivity that is greater than copper to facilitate still further improvement in performance of inductors. In contemplated embodiments, the composite conductive material may include known conductive metals, or conductive metal alloys, in combination with carbon nanotubes (hereinafter CNTs). Metals such as copper, silver or other metals and alloys, for example, may be enhanced with CNTs to provide superior electrical properties to those of the metal or metal alloys alone (i.e., the metal or metal alloys without CNTs).
For example, in various exemplary embodiments the composite conductive material may include 1-99% CNTs by weight to provide varying degrees of improved conductivity. In various contemplated embodiments, the composite conductive material including CNTs may be fabricated into flexible wire conductors that may be wound into a winding for assembly with a magnetic core piece, may be fabricated into layers of material from which conductors may be stamped and shaped into a desired geometric configuration, or may be deposited on substrate materials using known techniques. Single walled CNTs or multiple walled CNTs may be utilized and bonded to or otherwise joined with a metal or metal alloy to provide a composite material having improved conductivity relative to copper and other known metals that have been used to fabricate windings in conventional inductor fabrication. Consortiums of companies and universities have been established to develop such composite conductive materials and their manufacture.
In contemplated embodiments, a ratio of conductivity (I) of the composite conductive material including CNTs relative to that of copper may be within a range of, for example, about 1.1 to about 10.0. Such composite conductive materials are sometimes referred to as ultra-conductive materials due to their greatly increased conductivity relative to pure metals. Such ultra-conductivity is possible using such materials at room temperature, and is expressly contrasted with so-called superconductor materials that require cooling below critical temperatures in order to achieve nearly zero electrical resistance.
The use of new composite ultra-conductive materials to fabricate coils and windings in electromagnetic inductor component fabrication presents both great opportunities and great challenges to electromagnetic component manufacturers. The improved conductivity of the composite conductor materials provides much potential for improving electromagnetic performance, but the implications of its use leave much to be explored. As previously mentioned, because so much of the electromagnetic inductor component knowledge base has been built around copper-based windings, the relation between improved conductivity of windings and other important attributes of the electromagnetic inductor component are not immediately clear. Thus, the implementation of ultra-conductive materials may mean much more significant trial and error experimentation in relation to existing inductor designs, with much expense and associated delay in delivering electromagnetic inductor components that meet desired specifications.
In one aspect of the present invention, a methodology is proposed that facilitates adjusting/selecting electrical parameters associated with inductors, such as inductance, effective permeability, saturation current, DC resistance, diameter of the coil conductor, the number of turns, and core volume based on the ratio of conductivity of a selected composite ultra-conductive material to previously used conductive materials such as copper in the fabrication of electromagnetic inductor components. Previously known inductor designs can be effectively adapted for use with ultra-conductive materials with highly reliable results that may avoid the expense and delays of experiments that may otherwise be required to implement ultra-conductive materials in electromagnetic inductor component constructions. Advantageously, the ratio of conductivity can be utilized to fabricate inductors having ultra-conductive material windings with smaller core structures, or alternatively to provide inductors of approximately the same size as existing inductors but with much greater performance capability.
In another aspect, the invention proposes identifying a range (i.e. an upper limit and lower limit), of an effective diameter of a conductor used to fabricate the coil based on the ratio of conductivity of the composite material used to fabricate the coil and an effective diameter of a similarly configured inductor having a conventional metal coil of lower conductivity such as copper. More specifically, the invention proposes to identify upper and lower limits of a ratio of an effective diameter of the improved conductivity conductor relative to a reference conductor (e.g., a copper-based conductor) in a reference inductor. Based on a range defined by the ratio of conductivity of the composite material and coil conductor diameters (or range of ratio of effective diameter of an improved conductivity conductor relative to a reference effective diameter of a reference conductor fabricated from a lower conductivity material such as copper), values of any one of the following exemplary performance parameters may be selected: effective permeability of the magnetic core, saturation current for the component, direct current resistance (DCR), inductance value, number of turns, and core volume. When one of the parameter values is selected, the remaining ones of the parameters such as effective permeability of the core, saturation current, DC resistance, resultant inductance, number of turns, and core volume may be adjusted to provide an inductor with desired performance improvements. The magnetic core volume, which relates to the physical size of the completed inductor component, is determined by a Window Area (WA), Mean Length Per Turn (MLT), and Cross sectional Area (AC) as explained below, and these attributes too may be adjusted to vary the size of the inductor component fabrication including the ultra-conductive composite material.
In accordance with some of the contemplated embodiments, the ratio of electrical conductivity (β) of composite conductive material to that of copper used in a reference conductor of copper is greater than 1. The ratio of electrical conductivity (β) defines an upper limit and lower limit of a diameter ratio (δ) of the coil conductor formed of a composite conductive material relative to a diameter of reference coil conductor formed of copper in the reference inductor.
At a saturation current equal to that of the reference inductor, the inductance, core volume and the DC resistance is adjustable within a range/region defined by the ratio of electrical conductivity (β) and the diameter ratio (δ) to obtain desired values.
The “reference inductor” for the discussion herein is an inductor having a reference inductance value, reference direct current resistance (DCR) value, and a reference saturation current value. The reference inductor also includes a reference core structure having a reference effective permeability value, and a reference core volume including a reference Window Area (WA), a reference Mean Length Per Turn (MLT), and a reference Cross sectional Area (AC). Further, the reference inductor includes a coil formed of copper having a reference coil diameter, and a reference number of turns.
In accordance with embodiments of the present invention, the diameter of the coil conductor fabricated with ultra-conductive composite material in relation to a reference coil conductor made of copper used in the reference inductor is within a range of 1 to (1/β)1/2 (or β(−1/2)).
In accordance with embodiments of the invention, when the saturation current is equal to that of the reference inductor and when the diameter ratio (δ) of the conductor is within the range 1 and β−1/4, the inductor's desired value of inductance is within an upper limit defined by (δ−2) and a lower limit equal to 1. Further, a desired value of the direct current resistance (DCR) of the inductor is within an upper limit defined by [β(−1)*δ(−4)], and a lower limit defined by [β(−1)*δ(−2)]. A desired value of core volume of the inductor may be adjusted between an upper limit equal to 1, and a lower limit defined by (δ2). A desired value of the effective permeability of the inductor may be adjusted between an upper limit defined by δ2/3, and a lower limit defined by (δ2). Further, a desired value of the number of turns of coil of the inductor is adjusted between an upper limit defined by δ(−2), and a lower limit defined by (δ(−2/3)).
In accordance with some embodiments, at a saturation current equal to that of the reference inductor and diameter ratio (δ) within the range 1 and β−1/4, a desired value of the height of the Window Area (WA) within the core may be adjusted between an upper limit equal to 1, and a lower limit defined by (δ2). In such case the desired value of the number of turns of coil of the inductor is adjusted between an upper limit defined by (δ−2) and a lower limit equal to 1. A desired value of the effective permeability of the inductor is adjusted between an upper limit equal to 1 and a lower limit defined by (δ2).
In another aspect, when the saturation current is selected to be equal to that of the reference inductor and when the diameter ratio (δ) of the conductor is within the range β−1/4 to β−1/2, the inductor's desired value of inductance is adjusted between an upper limit defined by [β*δ2], and a lower limit equal to 1. Further, the core volume may be adjusted between an upper limit defined by [β*δ(4)], and a lower limit defined by (δ2). The inductor's desired value of DC resistance may be adjusted between an upper limit equal to 1, and a lower limit defined by [β(−1)*δ(−2)]. A desired value of the effective permeability of the inductor is adjusted between an upper limit defined by δ2/3, and a lower limit defined by [β(−2/3)*δ(−2/)]. A desired value of the number of turns in the coil winding of the inductor is adjusted between an upper limit defined by [β(2/3)*δ(2/3)], and a lower limit defined by (δ(−2/3)).
In accordance with some embodiments, when the saturation current is selected to be equal to that of the reference inductor and the diameter ratio (δ) is within the range β−1/4 to β−1/2, the height of the Window Area (WA) within the core may be adjusted between an upper limit defined by [β*δ(4)], and a lower limit defined by (δ2). In such case the desired value of a number of turns of the coil of the inductor may be adjusted between an upper limit defined by [β*δ2] and a lower limit equal to 1. Further a desired value of the effective permeability of the inductor may be adjusted between an upper limit equal to 1 and a lower limit defined by [β(−1)*δ(−2)].
Referring to
For example, magnetically responsive sheet materials may be provided to include soft magnetic particles dispersed in a binder material, and may be provided as freestanding thin layers or films that may be assembled in solid form, as opposed to semi-solid or liquid materials that are deposited on and supported by a substrate material. Soft magnetic powder particles may be used to make the magnetic composite sheets, including Ferrite particles, Iron (Fe) particles, Sendust (Fe—Si—Al) particles, MPP (Ni—Mo—Fe) particles, HighFlux (Ni—Fe) particles, Megaflux (Fe—Si Alloy) particles, iron-based amorphous powder particles, cobalt-based amorphous powder particles, and other suitable materials known in the art. Combinations of such magnetic powder particle materials may also be utilized if desired. The magnetic powder particles may be obtained using known methods and techniques. Optionally, the magnetic powder particles may be coated with an insulating material.
After being formed, the magnetic powder particles may be mixed and combined with a binder material. The binder material may be a polymer based resin having desirable heat flow characteristics in the layered construction of a magnetic core for higher current, higher power use of the component 100. The resin may further be thermoplastic or thermoset in nature, either of which facilitates lamination of the sheet layers provided with heat and pressure. Solvents and the like may optionally be added to facilitate the composite material processing. The composite powder particle and resin material may be formed and solidified into a definite shape and form, such as substantially planar and flexible thin sheets. Further details of pre-formed magnetic sheet layers are described in the commonly owned U.S. patent application Ser. No. 12/766,382, the entire disclosure of which is hereby incorporated by reference. Insulator sheets may be used in combination with magnetic sheets as desired, or the magnetic sheets may be joined in surface contact without any intervening layers between them.
The coil or winding 106 in the example shown in
In the example shown in
The inductor component 100 shown in
The component 120 shown in
An inductor component including the toroidal core 130 shown in
An inductor component including the EE core configuration 140 shown in
An inductor component including the ER core configuration 150 shown in
Figured 6A, 6B and 6C depict an exemplary UU core configuration 160 in plan view (
An inductor component including the UU core configuration 160 shown in Figured 6A, 6B and 6C may be referenced to a reference inductor of a similar configuration, but having a copper-based coil, and is but one example of a type of inductor component that may benefit from the design approach described herein. The leads of the winding may be connected to terminal clips that may, in turn, be surface mounted to a circuit board. Alternatively, the leads of the winding formed on the core 160 may be through-hole mounted to a circuit board. In some embodiments, the winding formed on the core 160 need not connect to a circuit board at all, but rather may be terminated to external circuitry using known connections and techniques.
An inductor component including the EPC core configuration 170 shown in
An inductor component including the PC core configuration 180 shown in
An inductor component including the DS core configuration 190 shown in
The inductor component 200 including the I core 202 may be referenced to a reference inductor of a similar configuration, but having a copper-based coil, and is but one example of a type of inductor component that may benefit from the design approach described herein. The leads of the winding may be connected to terminal clips that may, in turn, be surface mounted to a circuit board. Alternatively, the leads of the winding formed on the core 202 may be through-hole mounted to a circuit board. In some embodiments, the winding formed on the core 202 need not connect to a circuit board at all, but rather may be terminated to external circuitry using known connections and techniques.
It is understood that the core and coil configurations in the examples of
In all of the embodiments described above, the coils are fabricated from an ultra-conductive composite material. The composite conductive material utilized may contains 1-99% by weight of carbon nanotubes (CNTs) along with metal or metal alloys, such as copper, copper alloys, aluminum, or aluminum alloys. The ultra-conductive coil conductor including the CNTs may include a metal or metal alloy core, and carbon nanotube (CNT) cladding. In contemplated embodiments, the conductivity of the composite material may be about 1.1 to about 10 times that of copper. The ultra-conductive material used to fabricate the coils can be made using any suitable process.
Referring to
If a coil wire has cross-sectional shape other than round, as shown in the example of
A=πr2
where the diameter D of the circular cross section is equal to twice the radius r. In this example where A is 12 square units, the radius r can be computed and is seen to be 1.95. The diameter of a round cross section having the area of 12 is therefore twice the radius (e.g., 1.95×2) or 3.9. The conductor shown in
Of course, the exemplary conductors and cross sections illustrated in
For example, if each strand has a cross sectional area of 2 square units and seven strands are utilized as shown, the conductor 270 has a cross sectional area of 14. Using the relationship above, the radius r of a circle having an area of 14 square units can be computed. In this example, the radius r is 2.11 and the diameter D is therefore twice the radius (e.g., 2.11×2) or 4.22. The conductor shown in
Continuing the example above, if each conductor 270 has a cross sectional area of 14 square units (2 square units per strand times seven strands), the cross sectional area of the entire conductor 280 is seven times the cross sectional area of the conductor strands (e.g., 7 times 14 or 98 square units). The effective diameter of the conductor for the purposes of the invention is then the diameter of a solid round wire with equivalent cross-sectional area of the conductor 280. Using the relationship above, the radius r of a circle having an area of 98 square units can be computed. In this example, the radius r is 5.59 and the diameter D is therefore twice the radius r (e.g., 5.59×2) or 11.18. The conductor 280 shown in
In accordance with an embodiment of the present invention, the actual effective diameter of the conductor utilized to fabricate the coil(s) from composite ultra-conductive materials such as that described above including CNTs is dependent on the relative conductivity of the composite conductive material and is preferably within a range of about 1.0 to about (1/β)1/2 where β is a ratio of the conductivity of the composite conductive material to a conductivity of a reference material such as copper. For instance, if the conductivity of the composite conductive material (β) used to fabricate the coil(s) is two times that of copper, the effective diameter of the conductor fabricated from the composite material may range from about 0.707 to about 1.0 of the effective diameter of a copper-based coil. In other words, by using the composite ultra-conductive conductor material the effective diameter of the conductor can be reduced relative to a copper conductor to any value from 1 to 0.707 in this example, where “1” represents the effective diameter of the copper conductor. Thus, the composite conductor material can facilitate a significant reduction in the size of the coil, which in turn may facilitate a significant reduction in the size of the magnetic core structure. A significant reduction in the overall size of an electromagnetic inductor component may be realized.
A reduction in the effective diameter of the conductor utilized to fabricate the coil, made possible by the greater conductivity of the conductive material utilized, also may impact the number of turns required to obtain a desired inductance value and/or other performance parameters and attributes associated with inductor components shown in
In order to achieve these benefits, in one aspect the present invention utilizes a design approach referencing an existing or established electromagnetic inductor component having certain attributes. That is, reference may be made to a reference inductor that has a reference core fabricated from a selected magnetic material and a reference coil fabricated form a conventional metal material such as copper or copper alloy in one example. The conductivity of the copper material may be deemed a reference value of 1. Except as noted below. it is to be understood that the reference inductor and the inductor of the present invention have otherwise identical core shapes whether fabricated from the same magnetic materials as the core of the reference inductor. For instance, if the inductor of the present invention has a toroid shaped core then the reference inductor is assumed to have a toroid shaped core fabricated from the same magnetic material. For the sake of the present description, any parameter preceded by the word “reference” shall mean the corresponding parameter associated with the reference inductor, unless specified otherwise.
In accordance with contemplated embodiments of the present invention, a ratio of conductivity (simply referred to as conductivity ratio (I) in the rest of the specification) of the composite ultra-conductive material utilized to fabricate the conductor of the coil of the present invention, relative to that of the conductive material utilized to fabricate the coil of the reference inductor (e.g., copper) defines a range of effective diameter of the coil conductor. Alternatively, the conductivity ratio (β) defines a range of a ratio of effective diameter of the coil cross section of the present invention relative to that of the reference inductor's effective diameter of the coil cross section. This ratio of effective diameters will be simply referred to as a “diameter ratio” or (δ) in the rest of description. Further, for a given value of diameter ratio (δ) and conductivity ratio (β) of the composite conductive material utilized relative to the conductive material utilized in the reference inductor, some of the parameters of the inductor of the present invention, such as inductance (L), direct current Resistance (DCR), core volume (V), and saturation current (ISAT), can be adjusted to achieve a desired performance improvement. The word “adjusted” as used herein shall include the selection, alteration, variation or deviation from the respective reference parameters of the reference inductor. However, in certain embodiments, as will become apparent, such adjustments have to be made by keeping at least one of the parameters constant.
In accordance with embodiments of the present invention, if the conductivity of composite material used in the coil conductor is β times that of a reference copper conductor of the reference inductor, then the diameter ratio (δ) may be adjusted within a range of 1 to β−1/2. In one example, within a sub-range (1 to β−1/4) of the entire range 1 to (1/β)1/2, by keeping the saturation current (ISAT) equal to the saturation current of the reference inductor, the values of core volume (V), DC Resistance (DCR), inductance (L), number of turns (N) in the coil winding, and effective permeability (μ) can be adjusted to obtain desired values. The desired values of Inductance (L), DC Resistance (DCR), Core Volume (V), effective permeability of the core (μ), and number of turns (N) in the winding are adjustable within regions having upper limits defined by functions (δ−2), [β(−1)*δ(−4)], 1, β2/3, δ(−2) and lower limits defined by functions 1, [β(−1)*δ(−2)], (δ2), (δ2), (δ(−2/3)) respectively. It must be noted that the regions of improvement, wherein the desired values can be adjusted, are envisaged in relation to respective values of the same reference parameters.
The limits and functions referred to above are derived from relationships illustrated in graphical form in
However, if the diameter ratio (δ) is selected to be outside the limits of the bounded region 401 shown (i.e., outside the broken lines that bound the region 401), the inductance of the resultant component will be lower than the inductance value of the reference inductor. That a higher conductivity composite material may be utilized to provide an inductor with a lower inductance value than the reference inductor utilizing a conventional conductive material having a lower conductivity (but otherwise similar design) is perhaps a counterintuitive result that is preferably avoided. Thus, the bounded region 401 provides a range of values, within and including the boundaries shown in which the inductance value of an inductor component of the present invention constructed with values (β) and (δ) is the same or better in terms of its inductance value than the inductance value of the reference inductor.
Similarly, additional bounded design improvement regions 403, 405, 407, and 409 are shown in
The reader may recognize that the bounded regions 401, 403, 405, 407, and 409 shown in
In accordance with contemplated embodiments of the present invention, within a sub-range (β−1/4 to β−1/2) of the entire range 1-(1/β)1/2 of the diameter ratio (δ) shown in
Referring still to
In accordance with the embodiments described above, it is assumed that when the core volume (V) is improved (i.e., reduced) such improvement happens proportionally for all the sides or dimensions of the core structure (i.e., all the dimensions of the magnetic core structure shrink proportionally while the core structure shape and contour remains the same. In other words, the three dimensions of core volume that is Window Area (WA), Mean Length Per Turn (MLT), and Cross sectional Area (AC), as shown in the preceding figures, proportionally change with any change in core volume (V).
In certain embodiments, however, there exists a possibility where only the height of the Window Area (WA) would change and Mean Length Per Turn (MLT), and Cross-sectional Area (AC) would not change. In such case the Inductance (L) and DC Resistance (DCR) will have the improvements as shown in
As seen in
Similarly, and as also illustrated in
As illustrated in
Referring to
In the table of
Inductance values (L), saturation current values (ISAT), and direct current resistance values (DCR) are shown in the first column 700 for the SD3110 Series power inductor components listed. The SD3110 Series power inductors tabulated in the first column 700 include conductors fabricated from copper that are, in turn, used to define windings completing a number of turns in the SD3110 Series power inductor components. In other words, the column 700 lists a number of “reference inductors” and associated values for purposes of the present invention. The SD3110 Series power inductors represent one type of a reference inductor for which performance improvements are believed to have peaked when copper conductors are used to fabricate the coils and windings. Of course, other reference inductors having different coils are possible and may instead be utilized for purposes of the present invention.
The second column 702 shown in the Table of
As seen at the bottom of the second column 702, these results for the first set are obtained using an effective diameter conductor that is the same as the effective diameter of the reference inductors in the column 700 (i.e., the diameter ratio (δ) has been selected to equal 1). The effective permeability value (μ) is also selected to have a value of 1 in the first set shown in the column 702. As a result, inductors of the first set may be provided that include the same core construction and gap as the set of reference inductors, and maintain the same package size as the reference SD3110 Series power inductor of the same rating. The first set of inductors shown in the column 702, however, have dramatically better DCR performance relative to the reference inductors in column 700 by virtue of the improved conductivity of the composite conductive material utilized to fabricate the coils in the first set.
The third column 704 shown in the Table of
The fourth column 706 shown in the Table of
The findings in the Table of
As shown at step 652, a reference inductor component is selected or identified. The reference inductor component selected or identified, as described above, includes a reference magnetic core, a reference conductor material from which a coil and winding is fabricated, and the reference inductor component may have a reference core size and a plurality of reference performance parameters selected from the group of an inductance value, an effective permeability, a saturation current value, and a direct current resistance value when connected to electrical circuitry. The reference inductor component may be a power inductor in one embodiment, and may include any of the coil and winding configurations described above and any of the core structures described above. The reference inductor component may include a conductor material such as copper, copper alloy, silver, silver alloy, aluminum, or aluminum alloy. The selection or identification of the reference component at step 652 may include selecting or identifying a single component or a set of reference components such as those illustrated in the Table of
At step 654, a composite conductive material having a conductivity greater than a conductivity of the reference conductor material is provided. The composite material may be any material described above or another material of a greater conductivity than the conductor material utilized in the reference component(s). Varying degrees of conductivity may be provided by different formulations of composite materials. The composite materials may be provided in flexible wire form, sheet form, or in a form that may be deposited on a substrate material. In some embodiments, the step of providing the composite material at step 654 may include the step of manufacturing the composite conductive material. In other embodiments, the step of providing the composite material may include acquiring the material from another party, whether a manufacturer or a distributor, and making the composite material available for electromagnetic inductor component fabrication.
At step 656 a ratio is determined of electrical conductivity (β) of the composite conductor provided at step 654 to the electrical conductivity of the reference conductor material of for the reference inductor component selected at step 652. While illustrated as a separate step, step 656 and step 654 may in practice be one and the same in certain embodiments. That is, one may select the composite material provided at step 654 to achieve a desired conductivity ratio for purposes of step 656. Alternatively, a composite conductive material could be provided and analyzed to determine its conductivity, which can then be used to determine the conductivity ratio.
As shown at step 658, improvement regions such as those shown in
As shown at step 660, an upper limit and lower limit of an effective diameter of the composite conductive material may be determined based on the determined ratio of electrical conductivity (β). The upper and lower limits of the effective diameter may be determined in view of the regions provided at step 658 in one example. The upper and lower limits are determined from the perspective of identifying a range of values between the limits in which a component parameter may be improved relative to the reference inductor selected at step 652.
At step 662, an effective diameter within the determined upper and lower limit is selected. The effective diameter selection may be any value about equal to the upper and lower limit determined at step 660, or any value in between. The selected effective diameter value is made with an objective, as described above, of maintaining or improving a parameter of the reference component(s) selected at step 652. In some embodiments step 662 may be consolidated with steps 654 and 656. For example, only one composite conductor with a given effective diameter may be provided at step 654, such that the effective diameter at step 662 may be effectively dictated by the composite material provided.
At step 664, based on the selected effective diameter value at step 662, the effective diameter ratio of the conductor material provided is determined relative to the effective diameter of the reference component selected at step 652. As described above, the effective diameter ratio determined at step 664 may relate to a cross section of a conductor that is not round or circular in cross section.
At step 666, at least one component parameter may be selected to match a corresponding parameter of the reference component selected at step 652. For example, as described in some of the examples above, as well as some of the examples to follow, the saturation current (ISAT) for the component design including the composite conductive material may be selected to match the saturation current (ISAT) of the reference component selected at step 652. Alternatively, another parameter may be selected to match the corresponding of the reference component selected at step 652.
In at least some contemplated embodiments, and as shown in phantom in
It is understood, however, that multiple improvement regions and graphs may be generated in advance based on different possible selections being made at step 666, and in such a scenario the step 666 may be performed after the step 658 as shown in
At step 668, at least one other component parameter is selected in view of the selection made at step 666. In the example of the (ISAT) value being selected at step 666, another parameter (besides the (ISAT) value) may be selected to provide an improvement in the inductor being designed with respect to that parameter. The component being designed would therefore have the same parameter ((ISAT) in this example) as the reference component per the selection at step 666, but having an improved value with respect to the reference component regarding the parameter selected at step 668. The selection at step 668 may be made in reference to the regions provided in step 658 as illustrated in the examples above.
Following the example above, if the (ISAT) value is selected at step 666 to match the reference inductor, the other parameter selected at step 668 may be one of the inductance value (L), the direct current resistance (DCR) value, and the core size. Any value of L, DCR and core size may be selected within the bounded regions of the graphs provided at step 658. Parameters or characteristics other than L, DCR and core size are possible for selection at step 668 and may likewise be selected in another example.
Once the selections at steps 664, 666 and 668 are made, the remaining parameters of the component design are now determined. For example, considering a scenario wherein the ISAT value is selected at step 666 and wherein the inductance value (L) is selected at step 668, the direct current resistance (DCR) value and the core size or volume value flow from the previous selections made and must be used to obtain the selected values at steps 666 and 668. The number of turns (N) and the effective permeability value (μ) also flow from the previous selections made and must be used to obtain the selected values at steps 666 and 668. In other words, once one parameter (e.g., the ISAT value) is selected to match the reference inductor, and one another parameter is selected to obtain an improvement relative to the reference inductor, the remaining parameters are now determined and are required to obtain the desired improvement. Accordingly, at step 670 the required parameters are accepted. The required parameters may be determined using the bounded regions as further demonstrated in the examples below.
At step 674, a core structure is fabricated having the volume and permeability as selected or required by the preceding steps. Where the permeability value is 1.0, the core structure can be fabricated from the same material as the core structure in the reference conductor. Where the permeability is not equal to 1, the core structure can be fabricated from same magnetic material as the core structure of the reference inductor with the physical gap being adjusted to achieve the desired permeability value, or may alternatively be selected from another magnetic material to achieve the selected or required permeability. In embodiments wherein the core volume is changed, the core volume may be proportionally changed (decreased) in all dimensions relative to the reference component selected at step 352 while otherwise retaining the same shape as the reference inductor. In certain embodiments, however, only the winding area (WA) in the core may be adjusted relative to the reference conductor while the footprint and the component height remain the same as discussed above and as shown in some of the examples below. As in the examples described above, the core structure may be formed in one piece or multiple pieces having the same or different shape. At step 676, the coil is fabricated from the composite material provided at step 654, having the conductivity determined at step 656, and having the effective diameter ratio determined at step 664. The coil is formed with a number of turns required at step 670 to complete a winding that, in combination with the other parameters selected or required, achieves the desired improvement. Any of the techniques and coil configurations described above may be utilized to construct the coil at step 676.
At step 678, the core and coil are assembled to complete the electromagnetic component exhibiting the parameter values selected at steps 666 and 668. In some embodiments, the steps of 674, 676 and 678 may occur at the same time. As one such example, in a laminated component construction including magnetic sheets, the magnetic sheets may be pressed around the coil to fabricate the magnetic core structure. As another example, in a laminated component construction including layers successively formed on a preexisting layer, the coil may simultaneously be formed with the magnetic core structure. The component completed may be configured as a power inductor or the component may be configured as a non-power inductor, a transformer, or still other type of electromagnetic component as desired.
While an exemplary method 650 has been described, the method and process steps may be performed using less than all of the steps shown, with additional steps included and/or the method and process steps may be performed in a different order. Various adaptations are possible within the scope of the pending claims.
More specifically, a first exemplary set of points 702, represented by circles in
A second exemplary set of points 704, represented by squares in
A third exemplary set of points 706 is shown in
Other sets of points may be selected along the line 700 within the regions indicated to provide still other inductor embodiments of inductor components according to the invention including improved conductivity composite material but having other characteristics than the examples above defined by the points 702, 704 and 706. Considering other possible other possible values of effective diameter ratio (δ) values that may be selected to defines lines other than the line 700 shown in
Still further, a line (similar to the line 700) may be selected that coincides with the boundaries shown between the respective regions 421 and 401, the respective regions 423 and 403, and the respective regions 425 and 405. In such a case, it can be seen that the maximum inductance value L would be higher than the line 700 shown allows since the maximum inductance value peaks at this location. Viewing
It should now be appreciated that
Alternatively, as should be evident from
As shown in
Once the appropriate selections are made, as represented by the lines and points discussed above in relation to
As shown in
An inductor component according to the invention including improved conductivity composite material can then be constructed per steps 674, 676 and 678 to achieve the characteristics corresponding to the points 704 shown in
As shown in
The inductor component of the invention including improved conductivity composite material can then be constructed per steps 674, 676 and 678 to achieve characteristics corresponding to the points 706 shown in
The methodology illustrated in the relation to the exemplary graphs of
Except as described above, the selection of parameters to construct an inductor component according to the present invention including improved conductivity composite material in accord with
The benefits and advantages of the inventive concepts are now believed to have been amply illustrated in relation to the exemplary embodiments disclosed.
An embodiment of an electromagnetic inductor component has been disclosed including: a magnetic core; and a conductor fabricated from a conductive material having a first electrical conductivity, the conductor shaped to form a coil defining a winding completing a number of turns; and the conductor further shaped with a first cross sectional area and corresponding effective diameter that is determined by a ratio of electrical conductivity (β) of the first electrical conductivity of the conductor relative to a second electrical conductivity of a reference conductor in a reference electromagnetic inductor component; wherein the first electrical conductivity is greater than the second electrical conductivity.
Optionally, the ratio of electrical conductivity (β) may be within the range of about 1.1 to about 10. The conductive material having the first electrical conductivity may include a composite conductive material including carbon nanotubes. The conductive material may include 0.1% to 100%, by weight, of carbon nanotubes. The reference conductor material may be one of copper and a copper alloy. The cross sectional area may not be round.
Also optionally, the conductive material having a first electrical conductivity may be an ultra-conductive material. The reference conductor may be fabricated from one of copper, copper alloy, aluminum, aluminum alloy, silver, or silver alloy. The component may be configured as a power inductor. Alternatively, the component is configured as a non-power inductor.
Optionally, the ratio of electrical conductivity (β) may define an upper limit and a lower limit for the effective diameter of the conductor, and the effective diameter may be selected to be within a range defined by and including the upper and lower limits. The inductor component may be configured to operate with a plurality of performance parameters including an inductance value, an effective permeability, a saturation current value, a core size, a number of turns, and a direct current resistance value when connected to electrical circuitry; wherein one of the plurality of performance parameters may match a corresponding performance parameter of the reference inductor component, and wherein a performance value of at least one other of the plurality of performance parameters may be selected to be within one of a plurality of respective bounded regions defined as a function of at least one of the electrical conductivity ratio (β) and an effective diameter ratio (δ) of the conductor relative to the reference conductor material. A plurality of the performance parameters may each be respectively selected to be within the respective one of the plurality of bounded regions.
Optionally, the saturation current value matches a saturation current value for the reference inductor component. The effective diameter ratio (δ) may be within a range of about 1 to about β(−1/2).
As further options, the effective diameter ratio (δ) may be within a range of about 1 to about β−1/4. The inductance value may be selected from or determined by a bounded region defined by and between an upper boundary value defined by a function (δ−2) and a lower boundary value of 1.0. The direct current resistance (DCR) value is selected from or determined by a bounded region defined by and between an upper boundary valued defined by the function [β(−1)*δ(−4)] and a lower boundary value defined by a function [β(−1)*δ(−2)]. A core volume of the magnetic core may be selected from or determined by a bounded region defined by and between an upper boundary value of 1 and a lower boundary value defined by a function (δ2). The effective permeability of the magnetic core may be selected from or determined by a bounded region defined by and between an upper boundary defined by a function (δ2/3) and a lower boundary value defined by a function (δ2). A number of turns in the winding may be selected from or determined by a bounded region defined by and between an upper boundary defined by a function (δ−2) and a lower boundary value defined by a function (δ(−2/3)). The reference electromagnetic inductor component may further have a reference core and a reference core size; wherein a core size in the magnetic core is proportionally reduced relative to the reference core size; and wherein the core size in the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value of 1 and a lower boundary value defined by a function δ2. Alternatively, the reference electromagnetic inductor component may further have a reference core and a reference core size including a reference Window Area; wherein the height of the Window Area in the magnetic core is linearly reduced relative to the reference Window Area; and wherein the height of the Window Area in the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function (δ−2) and lower boundary value of 1. Still further, the reference electromagnetic inductor component further has a reference core and a reference core size; a core size in the magnetic core may be proportionally reduced relative to the reference core size; and an effective permeability of the magnetic core may be selected from or determined by a bounded region defined by and between an upper boundary value defined by a function (δ2/3) and a lower boundary value defined by a function (δ(2)).
Also, the reference electromagnetic inductor component may further have a reference core and a reference core size including a reference Window Area; wherein the height of the Window Area in the magnetic core is linearly reduced relative to the reference Window Area; and wherein an effective permeability of the magnetic core may be selected from or determined by a bounded region defined by and between an upper boundary value of 1 and a lower boundary value defined by a function (δ(−2)).
As still further options, an effective diameter ratio (δ) of the conductor relative to the reference conductor material may be within a range of about β−1/4 to about β−1/2. An inductance value of the component may be selected from or determined by a bounded region defined by and between an upper boundary value defined by a function [β*δ2] and a lower boundary value of 1. A direct current resistance (DCR) value of the component may be selected from or determined by a bounded region defined by and between an upper boundary value of 1 and a lower boundary value defined by a function [β(−1)*δ(−2)]. The reference electromagnetic inductor component may further have a reference core and a reference core size; wherein a core size in the magnetic core is proportionally reduced relative to the reference core size; and wherein a core size of the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function [β*δ(4)] and a lower boundary value defined by a function (δ2). Alternatively, the reference electromagnetic inductor component may further have a reference core and a reference core size including a reference Window Area; wherein the height of the Window Area in the magnetic core is linearly reduced relative to the reference Window Area; and wherein the height of the Window Area in the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function (β*δ2) and lower boundary value of 1. Further, the reference electromagnetic inductor component further has a reference core and a reference core size; wherein a core size in the magnetic core is proportionally reduced relative to the reference core size; and wherein an effective permeability of the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function δ2/3 and a lower boundary value defined by a function [β(−2/3)*δ(−2/3)]. Also, the reference electromagnetic inductor component further has a reference core and a reference core size including a reference Window Area; wherein the height of the Window Area in the magnetic core is linearly reduced relative to the reference Window Area; and wherein an effective permeability of the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value defined by a value of 1 and a lower boundary value defined by a function (β−1*δ−2). The reference electromagnetic inductor component may optionally further have a reference core and a reference core size; wherein a core size in the magnetic core is proportionally reduced relative to the reference core size; and wherein the number of turns may be selected from or determined by a bounded region defined by and between an upper boundary value defined by a function [β(2/3)*δ(2/3)] and a lower boundary defined by a function (δ(−2/3)). Alternatively, the reference electromagnetic inductor component may have a reference core and a reference core size including a reference Window Area; wherein the height of the Window Area in the magnetic core is linearly reduced relative to the reference Window Area; and wherein the number of turns of the winding is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function [β*δ2] and a lower boundary value of 1.
The magnetic core may optionally define a core volume containing the winding; wherein the core volume includes a Window Area (WA), a Mean Length Per Turn (MLT), and a Cross sectional Area (AC); and wherein one of the core volume and the selected number of turns is selected in view of one of the ratio of electrical conductivity (β) and the effective diameter ratio (δ) of the conductor relative to the reference conductor material.
A method of manufacturing an electromagnetic inductor component has also been disclosed including: selecting a reference inductor component including a reference magnetic core and a reference conductor material and having a plurality of reference performance parameters selected from the group of at least an inductance value, an effective permeability, a saturation current value, and a direct current resistance value when connected to electrical circuitry; providing a composite conductive material having a conductivity greater than a conductivity of the reference conductor material; determining a ratio of electrical conductivity (β) of the composite conductor relative to the electrical conductivity of the reference conductor material; based on the determined ratio of electrical conductivity (β), determining an upper limit and lower limit of an effective diameter of the composite conductive material; and selecting an effective diameter within the determined upper and lower limit.
Optionally, the method may also include fabricating a coil from the provided composite conductive material having the selected effective diameter and otherwise configured similarly to a reference coil in the reference inductor component. The electromagnetic inductor component may be configured to operate with performance parameters corresponding to the reference performance parameters when connected to electrical circuitry; and the method may further include: determining an effective diameter ratio (δ) of the composite conductor relative to the reference conductor material; and selecting a value of at least one of the performance parameters from within a respective region of values defined by a function of at least one of the ratio of electrical conductivity (β) and the effective diameter ratio (δ). The method may also include selecting a core volume value and a number of turns of the coil to be within a respective bounded region of values defined by at least one function of the ratio of electrical conductivity (β) and the effective diameter ratio (δ).
The method may also optionally include: fabricating a magnetic core having the selected core volume; and assembling a coil with the fabricated magnetic core, the coil being fabricated from the provided composite conductive material having the effective diameter, and the coil having a winding including the selected number of turns. Fabricating the magnetic core may include fabricating a magnetic core having a shape and volume that is proportionally decreased relative to the reference core of the reference inductor. Fabricating the magnetic core may also include fabricating a magnetic core having a window area height that is proportionally changed relative to the reference inductor.
Optionally, selecting values of at least one of the performance parameters may include selecting one of the performance parameters to match a corresponding one of the reference performance parameters, and selecting at least one other of the remaining performance parameters from one of the respective bounded regions of values, wherein each bounded region of values is defined by at an upper boundary or a lower boundary that is a function of at least one of the ratio of electrical conductivity (β) and the effective diameter ratio (δ). The method may further include fabricating an electromagnetic inductor component having a selected effective diameter and the selected conductivity value to achieve at least one of the selected performance parameters.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims
1. An electromagnetic inductor component comprising:
- a magnetic core; and
- a conductor fabricated from a conductive material having a first electrical conductivity, the conductor shaped to form a coil defining a winding completing a number of turns; and
- the conductor further shaped with a first cross sectional area and corresponding effective diameter that is determined by a ratio of electrical conductivity (β) of the first electrical conductivity of the conductor relative to a second electrical conductivity of a reference conductor in a reference electromagnetic inductor component;
- wherein the first electrical conductivity is greater than the second electrical conductivity.
2. The electromagnetic inductor component of claim 1, wherein the ratio of electrical conductivity (β) is within the range of about 1.1 to about 10.
3. The electromagnetic inductor component of claim 1, wherein the conductive material having the first electrical conductivity comprises a composite conductive material including carbon nanotubes.
4. The electromagnetic inductor component of claim 3, wherein the conductive material includes 0.1% to 100%, by weight, of carbon nanotubes.
5. The electromagnetic inductor component of claim 4, wherein the reference conductor material is one of copper and a copper alloy.
6. The electromagnetic inductor component of claim 1, wherein the conductive material having a first electrical conductivity comprises an ultra-conductive material.
7. The electromagnetic inductor component of claim 6:
- wherein the reference conductor is fabricated from one of copper, copper alloy, aluminum, aluminum alloy, silver, or silver alloy.
8. The electromagnetic inductor component of claim 1, wherein the component is configured as a power inductor.
9. The electromagnetic inductor component of claim 1, wherein the component is configured as a non-power inductor.
10. The electromagnetic inductor component of claim 1, wherein the cross sectional area is not round.
11. The electromagnetic inductor component of claim 1:
- wherein the ratio of electrical conductivity (β) defines an upper limit and a lower limit for the effective diameter of the conductor; and
- wherein the effective diameter is selected to be within a range defined by and including the upper and lower limits.
12. The electromagnetic inductor component of claim 11:
- wherein the inductor component is configured to operate with a plurality of performance parameters comprising an inductance value, an effective permeability, a saturation current value, a core size, a number of turns, and a direct current resistance value when connected to electrical circuitry; and
- wherein one of the plurality of performance parameters matches a corresponding performance parameter of the reference inductor component, and wherein a performance value of at least one other of the plurality of performance parameters is selected to be within one of a plurality of respective bounded regions defined as a function of at least one of the electrical conductivity ratio (β) and an effective diameter ratio (δ) of the conductor relative to the reference conductor material.
13. The electromagnetic inductor component of claim 12, wherein a plurality of the performance parameters is each respectively selected to be within the respective one of the plurality of bounded regions.
14. The electromagnetic inductor component of claim 12, wherein the saturation current value matches a saturation current value for the reference inductor component.
15. The electromagnetic inductor component of claim 14, wherein the effective diameter ratio (δ) is within a range of about 1 to about β(−1/2).
16. The electromagnetic inductor component of claim 15, wherein the effective diameter ratio (δ) is within a range of about 1 to about β−1/4.
17. The electromagnetic inductor component of claim 16, wherein the inductance value is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function (δ−2) and a lower boundary value of 1.0.
18. The electromagnetic inductor component of claim 16, wherein the direct current resistance (DCR) value is selected from or determined by a bounded region defined by and between an upper boundary valued defined by the function [β(−1)*δ(−4)] and a lower boundary value defined by a function [β(−1)*δ(−2)].
19. The electromagnetic inductor component of claim 16, wherein a core volume of the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value of 1 and a lower boundary value defined by a function (δ2).
20. The electromagnetic inductor component of claim 16, wherein the effective permeability of the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary defined by a function (δ2/3) and a lower boundary value defined by a function (δ2).
21. The electromagnetic inductor component of claim 16, wherein a number of turns in the winding is selected from or determined by a bounded region defined by and between an upper boundary defined by a function (δ−2) and a lower boundary value defined by a function (δ(−2/3)).
22. The electromagnetic inductor component of claim 16:
- wherein the reference electromagnetic inductor component further has a reference core and a reference core size;
- wherein a core size in the magnetic core is proportionally reduced relative to the reference core size; and
- wherein the core size in the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value of 1 and a lower boundary value defined by a function δ2.
23. The electromagnetic inductor component of claim 16:
- wherein the reference electromagnetic inductor component further has a reference core and a reference core size including a reference Window Area;
- wherein the height of the Window Area in the magnetic core is linearly reduced relative to the reference Window Area; and
- wherein the height of the Window Area in the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function (δ−2) and lower boundary value of 1.
24. The electromagnetic inductor component of claim 16:
- wherein the reference electromagnetic inductor component further has a reference core and a reference core size;
- wherein a core size in the magnetic core is proportionally reduced relative to the reference core size; and
- wherein an effective permeability of the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function (δ2/3) and a lower boundary value defined by a function (δ(2)).
25. The electromagnetic inductor component of claim 16:
- wherein the reference electromagnetic inductor component further has a reference core and a reference core size including a reference Window Area;
- wherein the height of the Window Area in the magnetic core is linearly reduced relative to the reference Window Area; and
- wherein an effective permeability of the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value of 1 and a lower boundary value defined by a function (δ(−2)).
26. The electromagnetic inductor component of claim 15, wherein an effective diameter ratio (δ) of the conductor relative to the reference conductor material is within a range of about β−1/4 to about β−1/2.
27. The electromagnetic inductor component of claim 26, wherein an inductance value of the component is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function [β*δ2] and a lower boundary value of 1.
28. The electromagnetic inductor component of claim 26, wherein a direct current resistance (DCR) value of the component is selected from or determined by a bounded region defined by and between an upper boundary value of 1 and a lower boundary value defined by a function [β(−1)*δ(−2)].
29. The electromagnetic inductor component of claim 26,
- wherein the reference electromagnetic inductor component further has a reference core and a reference core size;
- wherein a core size in the magnetic core is proportionally reduced relative to the reference core size; and
- wherein a core size of the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function [β*δ(4)] and a lower boundary value defined by a function (δ2).
30. The electromagnetic inductor component of claim 26:
- wherein the reference electromagnetic inductor component further has a reference core and a reference core size including a reference Window Area;
- wherein the height of the Window Area in the magnetic core is linearly reduced relative to the reference Window Area; and
- wherein the height of the Window Area in the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function (β*δ2) and lower boundary value of 1.
31. The electromagnetic inductor component of claim 26:
- wherein the reference electromagnetic inductor component further has a reference core and a reference core size;
- wherein a core size in the magnetic core is proportionally reduced relative to the reference core size; and
- wherein an effective permeability of the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function δ2/3 and a lower boundary value defined by a function [β(−2/3)*δ(−2/3)].
32. The electromagnetic inductor component of claim 26:
- wherein the reference electromagnetic inductor component further has a reference core and a reference core size including a reference Window Area;
- wherein the height of the Window Area in the magnetic core is linearly reduced relative to the reference Window Area; and
- wherein an effective permeability of the magnetic core is selected from or determined by a bounded region defined by and between an upper boundary value defined by a value of 1 and a lower boundary value defined by a function (β−1*δ−2).
33. The electromagnetic inductor component of claim 26:
- wherein the reference electromagnetic inductor component further has a reference core and a reference core size;
- wherein a core size in the magnetic core is proportionally reduced relative to the reference core size; and
- wherein the number of turns is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function [β(2/3)*δ(2/3)] and a lower boundary defined by a function (δ(−2/3)).
34. The electromagnetic inductor component of claim 26:
- wherein the reference electromagnetic inductor component further has a reference core and a reference core size including a reference Window Area;
- wherein the height of the Window Area in the magnetic core is linearly reduced relative to the reference Window Area; and
- wherein the number of turns of the winding is selected from or determined by a bounded region defined by and between an upper boundary value defined by a function [β*δ2] and a lower boundary value of 1.
35. The electromagnetic inductor component of claim 1:
- wherein the magnetic core defines a core volume containing the winding;
- wherein the core volume includes a Window Area (WA), a Mean Length Per Turn (MLT), and a Cross sectional Area (AC); and
- wherein one of the core volume and the selected number of turns is selected in view of one of the ratio of electrical conductivity (β) and the effective diameter ratio (δ) of the conductor relative to the reference conductor material.
36. A method of manufacturing an electromagnetic inductor component comprising:
- selecting a reference inductor component including a reference magnetic core and a reference conductor material and having a plurality of reference performance parameters selected from the group of at least an inductance value, an effective permeability, a saturation current value, and a direct current resistance value when connected to electrical circuitry;
- providing a composite conductive material having a conductivity greater than a conductivity of the reference conductor material;
- determining a ratio of electrical conductivity (β) of the composite conductor relative to the electrical conductivity of the reference conductor material;
- based on the determined ratio of electrical conductivity (β), determining an upper limit and lower limit of an effective diameter of the composite conductive material; and
- selecting an effective diameter within the determined upper and lower limit.
37. The method of claim 36, further comprising fabricating a coil from the provided composite conductive material having the selected effective diameter and otherwise configured similarly to a reference coil in the reference inductor component.
38. The method of claim 36, wherein the electromagnetic inductor component is configured to operate with performance parameters corresponding to the reference performance parameters when connected to electrical circuitry;
- wherein the method further comprises:
- determining an effective diameter ratio (δ) of the composite conductor relative to the reference conductor material; and
- selecting a value of at least one of the performance parameters from within a respective region of values defined by a function of at least one of the ratio of electrical conductivity (β) and the effective diameter ratio (δ).
39. The method of claim 36, further comprising selecting a core volume value and a number of turns of the coil to be within a respective bounded region of values defined by at least one function of the ratio of electrical conductivity (β) and the effective diameter ratio (δ).
40. The method of claim 39, further comprising:
- fabricating a magnetic core having the selected core volume; and
- assembling a coil with the fabricated magnetic core, the coil being fabricated from the provided composite conductive material having the effective diameter, and the coil having a winding including the selected number of turns.
41. The method of claim 40, wherein fabricating the magnetic core comprises fabricating a magnetic core having a shape and volume that is proportionally decreased relative to the reference core of the reference inductor.
42. The method of claim 40, wherein fabricating the magnetic core comprises fabricating a magnetic core having a window area height that is proportionally changed relative to the reference inductor.
43. The method of claim 38, wherein selecting values of at least one of the performance parameters comprises selecting one of the performance parameters to match a corresponding one of the reference performance parameters, and selecting at least one other of the remaining performance parameters from one of the respective bounded regions of values, wherein each bounded region of values is defined by at an upper boundary or a lower boundary that is a function of at least one of the ratio of electrical conductivity (β) and the effective diameter ratio (δ).
44. The method of claim 44, further comprising fabricating an electromagnetic inductor component having a selected effective diameter and the selected conductivity value to achieve at least one of the selected performance parameters.
Type: Application
Filed: Oct 10, 2014
Publication Date: Jun 23, 2016
Inventors: Frank Anthony Doljack (Pleasanton, CA), Ramdev Kanapady (Campbell, CA), Hundi Panduranga Kamath (Los Altos, CA)
Application Number: 14/511,266
