U.S. patent application number 14/511266 was filed with the patent office on 2016-06-23 for optimized electromagnetic inductor component design and methods including improved conductivity composite conductor material.
The applicant listed for this patent is COOPER TECHNOLOGIES COMPANY. Invention is credited to Frank Anthony Doljack, Hundi Panduranga Kamath, Ramdev Kanapady.
Application Number | 20160181001 14/511266 |
Document ID | / |
Family ID | 56130244 |
Filed Date | 2016-06-23 |
United States Patent
Application |
20160181001 |
Kind Code |
A1 |
Doljack; Frank Anthony ; et
al. |
June 23, 2016 |
OPTIMIZED ELECTROMAGNETIC INDUCTOR COMPONENT DESIGN AND METHODS
INCLUDING IMPROVED CONDUCTIVITY COMPOSITE CONDUCTOR MATERIAL
Abstract
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.
Inventors: |
Doljack; Frank Anthony;
(Pleasanton, CA) ; Kanapady; Ramdev; (Campbell,
CA) ; Kamath; Hundi Panduranga; (Los Altos,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
COOPER TECHNOLOGIES COMPANY |
Houston |
TX |
US |
|
|
Family ID: |
56130244 |
Appl. No.: |
14/511266 |
Filed: |
October 10, 2014 |
Current U.S.
Class: |
336/221 ;
29/606 |
Current CPC
Class: |
H01F 27/2823 20130101;
H01F 41/04 20130101; H01F 27/24 20130101; H01F 17/04 20130101; H01F
41/0206 20130101; H01F 17/0033 20130101 |
International
Class: |
H01F 27/24 20060101
H01F027/24; H01F 41/04 20060101 H01F041/04; H01F 41/02 20060101
H01F041/02; H01F 27/28 20060101 H01F027/28 |
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 (.beta.) 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 (.beta.) 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 (.beta.) 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 (.beta.) and an effective
diameter ratio (.delta.) 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 (.delta.) is within a range of about 1 to
about .beta.(.sup.-1/2).
16. The electromagnetic inductor component of claim 15, wherein the
effective diameter ratio (.delta.) is within a range of about 1 to
about .beta..sup.-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 (.delta..sup.-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
[.beta..sup.(-1)*.delta..sup.(-4)] and a lower boundary value
defined by a function [.beta..sup.(-1)*.delta..sup.(-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
(.delta..sup.2).
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 (.delta..sup.2/3) and a lower
boundary value defined by a function (.delta..sup.2).
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 (.delta..sup.-2) and a lower boundary value defined by a
function (.delta..sup.(-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 .delta..sup.2.
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
(.delta..sup.-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 (.delta..sup.2/3) and a lower boundary value defined by a
function (.delta..sup.(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 (.delta..sup.(-2)).
26. The electromagnetic inductor component of claim 15, wherein an
effective diameter ratio (.delta.) of the conductor relative to the
reference conductor material is within a range of about
.beta..sup.-1/4 to about .beta..sup.-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 [.beta.*.delta..sup.2] 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 [.beta..sup.(-1)*.delta..sup.(-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
[.beta.*.delta..sup.(4)] and a lower boundary value defined by a
function (.delta..sup.2).
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
(.beta.*.delta..sup.2) 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 .delta..sup.2/3 and a lower boundary value defined by a
function [.beta..sup.(-2/3)*.delta..sup.(-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 (.beta..sup.-1*.delta..sup.-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
[.beta..sup.(2/3)*.delta..sup.(2/3)] and a lower boundary defined
by a function (.delta..sup.(-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 [.beta.*.delta..sup.2] 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 (.beta.) and the effective
diameter ratio (.delta.) 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 (.beta.) of the composite
conductor relative to the electrical conductivity of the reference
conductor material; based on the determined ratio of electrical
conductivity (.beta.), 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 (.delta.) 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 (.beta.) and
the effective diameter ratio (.delta.).
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 (.beta.) and the
effective diameter ratio (.delta.).
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
(.beta.) and the effective diameter ratio (.delta.).
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.
Description
BACKGROUND OF THE INVENTION
[0001] 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.
[0002] 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.
[0003] 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.
[0004] 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.
[0005] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] 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.
[0007] FIG. 1 is an exploded view of a first exemplary embodiment
of an electromagnetic inductor component formed in accordance with
an exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0008] FIG. 2 is an exploded view of a second exemplary embodiment
an electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0009] FIGS. 3A, 3B and 3C depict an exemplary magnetic core
configuration in plan view in FIG. 3A, cross sectional view in FIG.
3B and in perspective view in FIG. 3C that may be utilized in an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0010] FIGS. 4A, 4B and 4C depict an exemplary magnetic core
configuration in plan view in FIG. 4A, cross sectional view in FIG.
4B and in perspective view in FIG. 4C that may be utilized in an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0011] FIG. 5A, 5B and 5C depict an exemplary magnetic core
configuration in plan view in FIG. 5A, cross sectional view in FIG.
5B and in perspective view in FIG. 5C that may be utilized in an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0012] FIGS. 6A, 6B and 6C depict an exemplary magnetic core
configuration in plan view in FIG. 6A, cross sectional view in FIG.
6B and in perspective view in FIG. 6C that may be utilized in an
exemplary embodiment of an electromagnetic inductor component
formed in accordance with an exemplary embodiment of the invention
and including an improved conductivity composite conductor
material.
[0013] FIGS. 7A, 7B and 7C depict an exemplary magnetic core
configuration in plan view in FIG. 7A, cross sectional view in FIG.
7B and in perspective view in FIG. 7C that may be utilized in an
exemplary embodiment of an electromagnetic inductor component
formed in accordance with an exemplary embodiment of the invention
and including an improved conductivity composite conductor
material.
[0014] FIGS. 8A, 8B and 8C depict an exemplary magnetic core
configuration in plan view in FIG. 8A, cross sectional view in FIG.
8B and in perspective view in FIG. 8C that may be utilized in an
exemplary embodiment of an electromagnetic inductor component
formed in accordance with an exemplary embodiment of the invention
and including an improved conductivity composite conductor
material.
[0015] FIGS. 9A, 9B and 9C depict an exemplary magnetic core
configuration in plan view in FIG. 9A, cross sectional view in FIG.
9B and in perspective view in FIG. 9C that may be utilized in an
exemplary embodiment of an electromagnetic inductor component
formed in accordance with an exemplary embodiment of the invention
and including an improved conductivity composite conductor
material.
[0016] FIG. 10A and 10B depict an exemplary embodiment of an
electromagnetic inductor component including a magnetic core
configuration in plan view in FIG. 10A, and in cross sectional view
in FIG. 10B that may be utilized in an exemplary embodiment of an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0017] FIG. 11 is a perspective view of an exemplary coil
configuration that may be utilized in an exemplary embodiment of an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0018] FIG. 12 is a perspective view of an exemplary coil
configuration that may be utilized in an exemplary embodiment of an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0019] FIG. 13 is a perspective view of an exemplary coil
configuration that may be utilized in an exemplary embodiment of an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0020] FIG. 14 is a perspective view of an exemplary coil
configuration that may be utilized in an exemplary embodiment of an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0021] FIG. 15 is a perspective view of an exemplary coil
configuration that may be utilized in an exemplary embodiment of an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0022] FIG. 16 illustrates a number of alternative cross sections
of conductors that may be utilized to fabricate a coil in an
exemplary embodiment of an electromagnetic inductor component
formed in accordance with an exemplary embodiment of the invention
and including an improved conductivity composite conductor
material.
[0023] FIG. 17 illustrates an exemplary conductor that may be
utilized to fabricate a coil in an exemplary embodiment of an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0024] FIG. 18 illustrates an exemplary conductor that may be
utilized to fabricate a coil in an exemplary embodiment of an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0025] FIG. 19 is an exemplary inductor design graph showing
optimal regions of performance improvement for an exemplary
embodiment of an electromagnetic inductor component formed in
accordance with an exemplary embodiment of the invention and
including an improved conductivity composite conductor
material.
[0026] FIG. 20 is another exemplary inductor design graph showing
optimal regions of performance for an exemplary embodiment of an
electromagnetic inductor component formed in accordance with an
exemplary embodiment of the invention and including an improved
conductivity composite conductor material.
[0027] FIG. 21 illustrates a comparative size reduction of an
exemplary embodiment of an electromagnetic inductor component
formed in accordance with an exemplary embodiment of the invention
versus a conventional inductor component of a similar configuration
and including an improved conductivity composite conductor
material.
[0028] FIG. 22 is a comparison table highlighting design
improvements with respect to DC Resistance and Inductance for a
series of inductor components formed in accordance with exemplary
embodiments of the invention including an improved conductivity
composite conductor material and wherein a saturation current value
is fixed with respect to a conventional set of inductor
components.
[0029] FIG. 23 illustrates an exemplary flowchart of a method of
designing and manufacturing electromagnetic inductor components in
accordance with exemplary embodiments of the present invention
including an improved conductivity composite conductor
material.
[0030] FIG. 24 is an exemplary design improvement region graph
similar to FIG. 19 but showing different points of possible
improvement for an inductor component formed in accordance with an
exemplary embodiment of the present invention including an improved
conductivity composite conductor material.
[0031] FIG. 25 is a magnified view of a portion of FIG. 24
illustrating selection of a first set of design characteristics of
an inductor component formed in accordance with an exemplary
embodiment of the present invention including an improved
conductivity composite conductor material.
[0032] FIG. 26 is a magnified view of another portion of FIG. 24
and further illustrating another portion of the first set of design
characteristics.
[0033] FIG. 27 is another view similar to FIG. 25 but illustrating
a second set of design characteristics of an electromagnetic
component formed in accordance with an exemplary embodiment of the
present invention including an improved conductivity composite
conductor material.
[0034] FIG. 28 is a magnified view similar to FIG. 26 and further
illustrating the second set of design characteristics.
[0035] FIG. 29 is another view similar to FIG. 25 but illustrating
a third set of design characteristics of an electromagnetic
component formed in accordance with an exemplary embodiment of the
present invention and including an improved conductivity composite
conductor material.
[0036] FIG. 30 is a magnified view similar to FIG. 26 and further
illustrating the second set of design characteristics.
[0037] FIG. 31 is another graphical illustration highlighting a
first one of multiple design improvement regions for an inductor
component formed in accordance with an exemplary embodiment of the
present invention and including an improved conductivity composite
conductor material.
[0038] FIG. 32 is a view similar to FIG. 31 but highlighting a
second one of multiple design improvement regions for the inductor
component of the invention.
[0039] FIG. 33 is a view similar to FIG. 31 but illustrating a
third one of multiple design improvement regions for the inductor
component of the invention.
[0040] FIG. 34 is another graphical illustration highlighting a
fourth one of multiple design improvement regions for the inductor
component formed in accordance with aspects of FIGS. 31-33.
[0041] FIG. 35 is a view similar to FIG. 34 but illustrating a
fifth one of multiple design improvement regions for the inductor
of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0042] 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.
[0043] 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.
[0044] 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.
[0045] 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.
[0046] 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.
[0047] 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.
[0048] 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.
[0049] 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.
[0050] 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.
[0051] 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.
[0052] 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).
[0053] 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.
[0054] 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.
[0055] 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.
[0056] 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.
[0057] 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.
[0058] In accordance with some of the contemplated embodiments, the
ratio of electrical conductivity (.beta.) of composite conductive
material to that of copper used in a reference conductor of copper
is greater than 1. The ratio of electrical conductivity (.beta.)
defines an upper limit and lower limit of a diameter ratio
(.delta.) 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.
[0059] 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 (.beta.) and the diameter ratio (.delta.) to obtain
desired values.
[0060] 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.
[0061] 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/.beta.).sup.1/2 (or .beta..sup.(-1/2)).
[0062] In accordance with embodiments of the invention, when the
saturation current is equal to that of the reference inductor and
when the diameter ratio (.delta.) of the conductor is within the
range 1 and .beta..sup.-1/4, the inductor's desired value of
inductance is within an upper limit defined by (.delta..sup.-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 [.beta..sup.(-1)*.delta..sup.(-4)], and a lower limit
defined by [.beta..sup.(-1)*.delta..sup.(-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 (.delta..sup.2). A desired
value of the effective permeability of the inductor may be adjusted
between an upper limit defined by .delta..sup.2/3, and a lower
limit defined by (.delta..sup.2). Further, a desired value of the
number of turns of coil of the inductor is adjusted between an
upper limit defined by .delta..sup.(-2), and a lower limit defined
by (.delta..sup.(-2/3)).
[0063] In accordance with some embodiments, at a saturation current
equal to that of the reference inductor and diameter ratio
(.delta.) within the range 1 and .beta..sup.-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 (.delta..sup.2). In such case the desired value of the
number of turns of coil of the inductor is adjusted between an
upper limit defined by (.delta..sup.-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 (.delta..sup.2).
[0064] In another aspect, when the saturation current is selected
to be equal to that of the reference inductor and when the diameter
ratio (.delta.) of the conductor is within the range
.beta..sup.-1/4 to .beta..sup.-1/2, the inductor's desired value of
inductance is adjusted between an upper limit defined by
[.beta.*.delta..sup.2], and a lower limit equal to 1. Further, the
core volume may be adjusted between an upper limit defined by
[.beta.*.delta..sup.(4)], and a lower limit defined by
(.delta..sup.2). The inductor's desired value of DC resistance may
be adjusted between an upper limit equal to 1, and a lower limit
defined by [.beta..sup.(-1)*.delta..sup.(-2)]. A desired value of
the effective permeability of the inductor is adjusted between an
upper limit defined by .delta..sup.2/3, and a lower limit defined
by [.beta..sup.(-2/3)*.delta..sup.(-2/)]. A desired value of the
number of turns in the coil winding of the inductor is adjusted
between an upper limit defined by
[.beta..sup.(2/3)*.delta..sup.(2/3)], and a lower limit defined by
(.delta..sup.(-2/3)).
[0065] In accordance with some embodiments, when the saturation
current is selected to be equal to that of the reference inductor
and the diameter ratio (.delta.) is within the range
.beta..sup.-1/4 to .beta..sup.-1/2, the height of the Window Area
(WA) within the core may be adjusted between an upper limit defined
by [.beta.*.delta..sup.(4)], and a lower limit defined by
(.delta..sup.2). 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 [.beta.*.delta..sup.2] 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 [.beta..sup.(-1)*.delta..sup.(-2)].
[0066] Referring to FIG. 1, an exemplary inductor component 100 is
shown that may be fabricated in accordance with an embodiment of
the present invention. The inductor 100 includes a first core piece
102, a second core piece 104, and a coil or winding 106. The core
pieces 102, 104 are each formed from materials having a desired
magnetic permeability. More specifically, the core pieces 102, 104
can be fabricated from iron, iron alloys, or ferrimagnetic ceramic
materials, other suitable magnetic materials, and combinations
thereof. Each core piece 102, 104 can be independently fabricated
into the shapes shown (which in the examples of FIGS. 1 and 2 are
different from one another) using granular powder materials.
Alternatively, one or both of the core pieces 102, 104 can be
fabricated by stacking multiple blocks or sheets of magnetic
material that may be pre-formed in some embodiments. In still other
embodiments, a monolithic, single piece core construction may be
provided to include the coil 106 in lieu of the two discrete core
pieces 102, 104 as shown.
[0067] 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.
[0068] 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.
[0069] The coil or winding 106 in the example shown in FIG. 1
includes a generally flat and planar main winding section 110,
first and second legs 112, 114 extending from either end of the
main winding section 110 in an orientation generally perpendicular
to the main winding section 110, and first and second terminal
sections 116, 118 extending from the legs 112, 114 in a generally
parallel orientation to the main winding section 110. The terminal
sections 116, 118 define surface mount areas for connection of
circuitry on a circuit board (not shown) via, for example, surface
mount, soldering techniques. The coil 106 may be fabricated from a
planar piece of composite, ultra-conductive material described
above, and subsequently bent or otherwise shaped in the
configuration shown that is sometimes referred to as a C-shaped
configuration due to its resemblance in side profile. While one
coil 106 is shown in the example of FIG. 1, more than one coil may
be provided. In a multiple coil embodiment, the coils may be
arranged in a flux sharing relationship with one another.
[0070] In the example shown in FIG. 1, the coil 106 may be
pre-formed and provided for assembly with the core pieces 102, 104.
The pre-formed coil 106 may first be assembled to the core piece
104 with sliding engagement in a horizontal direction in the
drawing of FIG. 1. The core piece 102 may then be assembled over
the core piece 104 and assembled coil 106. When assembled, the main
winding section 110 of the ultra-conductive coil 106 extends
between the facing core pieces 102 and 104. A physical gap,
represented by the element 119 in FIG. 1 may be established in a
known manner, and may be an air gap or a non-magnetic gap
established with a solid material that lacks magnetic properties.
Alternatively, the core structure may be fabricated using so-called
distributed gap materials, such as with the pre-formed magnetic
sheet layers described above, and therefore avoid any need to
provide physical gaps (whether via air or non-magnetic materials)
in the core structure. The core structure in the example shown
generally has a volume that is a function of a Window Area (WA) to
be occupied by the coil, Mean Length Per Turn (MLT) for the coil,
and Cross-sectional Area (AC) of the core structure where the coil
resides.
[0071] The inductor component 100 shown in FIG. 1 may be referenced
to a reference inductor of a similar configuration, but having a
copper-based coil 106, and is but one example of a type of inductor
component 100 that may benefit from the design approach described
herein. The inductor component 100 is advantageously compact and
may be assembled in a relatively simple manufacturing process to
produce a miniaturized inductor component for a circuit board
application. The pre-formed core pieces 102, 104 and the pre-formed
coil 106 avoid certain manufacturing difficulties and undesirable
performance fluctuation associated with winding a flexible
conductor or otherwise forming a coil around small core pieces 102,
104. The pre-formed coil 106 is further configured with a greater
cross sectional area to handle a higher current, higher power
application while still providing a small, low profile component.
The configuration of the inductor component 100 shown beneficially
provides an efficient power inductor at an economical cost.
[0072] FIG. 2 shows another exemplary inductor component 120 that
may be fabricated in accordance with an embodiment of the present
invention. The inductor 120 includes a first core piece 122, a
second core piece 124, and a coil or winding 126. The core pieces
122, 124 are each formed from materials having a desired magnetic
permeability, such as those described above. The coil 126 may be
fabricated from an ultra-conductive composite material such as
those described above. The shapes of the core pieces 122, 124 are
seen to be different from those shown in FIG. 1, and the coil 126
may be shaped over the surface of the core piece 104 into a
C-shaped configuration similar to that described above in relation
to the coil 106 (FIG. 1). The core pieces 122, 124 may be gapped,
as represented by the element 128 when the core piece 122 is
assembled over the core piece 124 and the coil 126 in a similar
manner to those discussed above. The core structure in the example
shown generally has a volume that is a function of a Window Area
(WA) to be occupied by the coil, Mean Length Per Turn (MLT) for the
coil, and Cross-sectional Area (AC) of the core structure where the
coil resides.
[0073] The component 120 shown in FIG. 2 may be referenced to a
reference inductor of a similar configuration, but having a
copper-based coil 126, and is but one example of a type of inductor
component that may benefit from the design approach described
herein. The component 120 is advantageously compact and may be
assembled in a relatively simple manufacturing process to produce a
miniaturized inductor component for a circuit board application.
The coil 126 is further configured with a greater cross sectional
area to handle a higher current application while still providing a
small, low profile component. The configuration of the component
120 shown beneficially provides an efficient power inductor at an
economical cost. The core structure in the example shown generally
has a volume that is a function of a Window Area (WA) to be
occupied by the coil, Mean Length Per Turn (MLT) for the coil, and
Cross-sectional Area (AC) of the core structure where the coil
resides.
[0074] FIGS. 3A, 3B, 3C depict an exemplary toroidal core
configuration 130 in plan view (FIG. 3A), cross sectional view
(FIG. 3B) and in perspective view (FIG. 3C) that may be utilized in
accordance with an exemplary embodiment of an inductor component in
accordance with the present invention. The toroidal core 130 may be
fabricated from magnetic materials such as those described above. A
composite, ultra-conductive conductor such as a wire (not shown in
FIGS. 3A, 3B, 3C) may be wound on the surface of the toroidal core
130 to complete a winding in a known manner and provide an inductor
component. The toroidal core 130 in the example shown generally has
a volume that is a function of Window Area (WA) where the coil is
applied, Mean Length Per Turn (MLT) for the coil, and
Cross-sectional Area (AC). FIG. 3A shows a Window Area 132 and a
Cross-sectional Area 134 is shown in FIG. 3B.
[0075] An inductor component including the toroidal core 130 shown
in FIGS. 3A, 3B, 3C 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 130 may be through-hole mounted to a circuit
board. In some embodiments, the winding formed on the core 130 need
not connect to a circuit board at all, but rather may be terminated
to external circuitry using known connections and techniques.
[0076] FIG. 4A, 4B, 4C depict an exemplary EE core configuration
140 in plan view (FIG. 4A) and including first and second core
pieces 142 that are identically shaped but assembled in a reverse
or mirror-image arrangement with respect to one another. The core
pieces 142 may be fabricated from magnetic materials such as those
described above. The EE core configuration 140 is shown in cross
section in FIG. 4B and the core piece 142 is shown in perspective
view (FIG. 4C). The EE core configuration 140 may be utilized in
accordance with an exemplary embodiment of the invention when a
composite, ultra-conductive wire (not shown in FIG. 4) is wound on
the surface of the EE core configuration 140 to complete a winding
in a known manner and provide an inductor component. Alternatively,
a pre-formed coil including a winding may be provided and assembled
with the core pieces 142 to complete the inductor component. The EE
core configuration 140 in the example shown generally has a volume
that is a function of Window Area (WA) where the coil is applied,
Mean Length Per Turn (MLT) for the coil, and Cross-sectional Area
(AC). FIG. 4A shows a Window Area 144 and a Cross-sectional Area
146 associated with the coil is shown in FIG. 4B.
[0077] An inductor component including the EE core configuration
140 shown in FIGS. 4A, 4B, 4C 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 140 may be through-hole mounted to a
circuit board. In some embodiments, the winding formed on the core
140 need not connect to a circuit board at all, but rather may be
terminated to external circuitry using known connections and
techniques.
[0078] FIGS. 5A, 5B and 5C depict an exemplary ER core
configuration 150 in plan view (FIG. 5A) and including first and
second core pieces 152 that are identically shaped but assembled in
a reverse or mirror-image arrangement with respect to one another.
The core pieces 152 may be fabricated from magnetic materials such
as those described above. The ER core configuration 150 is shown in
cross section in FIG. 5B and the core piece 152 is shown in
perspective view (FIG. 5C). The ER core configuration 150 may be
utilized in accordance with an exemplary embodiment of the
invention when a composite, ultra-conductive wire (not shown in
FIGS. 5A, 5B, 5C) is wound on the surface of the ER core
configuration 150 to complete a coil in a known manner and provide
an inductor component. Alternatively, a pre-formed coil may be
provided and assembled with the core pieces 152 to complete the
inductor component. The ER core configuration 150 in the example
shown generally has a volume that is a function of Window Area (WA)
where the coil is applied, Mean Length Per Turn (MLT) for the coil,
and Cross-sectional Area (AC). FIG. 5A shows a Window Area 154 and
a Cross-sectional Area 156 associated with the coil is shown in
FIG. 5B.
[0079] An inductor component including the ER core configuration
150 shown in FIGS. 5A, 5B and 5C 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 150 may be through-hole mounted to a
circuit board. In some embodiments, the winding formed on the core
150 need not connect to a circuit board at all, but rather may be
terminated to external circuitry using known connections and
techniques.
[0080] Figured 6A, 6B and 6C depict an exemplary UU core
configuration 160 in plan view (FIG. 6A) and including first and
second core pieces 162 that are identically shaped but assembled in
a reverse or mirror-image arrangement with respect to one another.
The core pieces 162 may be fabricated from magnetic materials such
as those described above. The UU core configuration 160 is shown in
cross section in FIG. 6B and the core piece 162 is shown in
perspective view (FIG. 6C). The UU core configuration 160 may be
utilized in accordance with an exemplary embodiment of the
invention when a composite, ultra-conductive wire (not shown in
FIGS. 6A, 6B, 6C) is wound on the surface of the UU core
configuration 160 to complete a coil in a known manner and provide
an inductor component. Alternatively, a pre-formed coil may be
provided and assembled with the core pieces 162 to complete the
inductor component. The UU core configuration 160 in the example
shown generally has a volume that is a function of Window Area (WA)
where the coil is applied, Mean Length Per Turn (MLT) for the coil,
and Cross-sectional Area (AC). FIG. 6A shows a Window Area 164 and
a Cross-sectional Area 166 associated with the coil is shown in
FIG. 6B.
[0081] 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.
[0082] FIG. 7A, 7B and 7C depict an exemplary EPC core
configuration 170 in plan view (FIG. 7B) and including first and
second core pieces 172 that are identically shaped but assembled in
a reverse or mirror-image arrangement with respect to one another.
The core pieces 172 may be fabricated from magnetic materials such
as those described above. The EPC core configuration 170 is shown
in cross section in FIG. 7A and the core piece 172 is shown in
perspective view (FIG. 7C). The EPC core configuration 170 may be
utilized in accordance with an exemplary embodiment of the
invention when a composite, ultra-conductive wire (not shown in
FIGS. 7A, 7B, 7C) is wound on the surface of the EPC core
configuration 170 to complete a coil in a known manner and provide
an inductor component. Alternatively, a pre-formed coil may be
provided and assembled with the core pieces 172 to complete the
inductor component. The EPC core configuration 170 in the example
shown generally has a volume that is a function of Window Area (WA)
where the coil is applied, Mean Length Per Turn (MLT) for the coil,
and Cross-sectional Area (AC). FIG. 7B shows a Window Area 174 and
a Cross-sectional Area 176 associated with the coil is shown in
FIG. 7A.
[0083] An inductor component including the EPC core configuration
170 shown in FIGS. 7A, 7B and 7C 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 170 may be through-hole mounted to a
circuit board. In some embodiments, the winding formed on the core
170 need not connect to a circuit board at all, but rather may be
terminated to external circuitry using known connections and
techniques.
[0084] FIGS. 8A, 8B and 8C depict an exemplary PC core
configuration 180 in plan view (FIG. 8B) and including first and
second core pieces 182 that are identically shaped but assembled in
a reverse or mirror-image arrangement with respect to one another.
The core pieces 182 may be fabricated from magnetic materials such
as those described above. The PC core configuration 180 is shown in
cross section in FIG. 8A and the core piece 182 is shown in
perspective view (FIG. 8C). The PC core configuration 180 may be
utilized in accordance with an exemplary embodiment of the
invention when a composite, ultra-conductive wire (not shown in
FIGS. 8A, 8B and 8C) is wound on the surface of the EPC core
configuration 180 to complete a coil in a known manner and provide
an inductor component. Alternatively, a pre-formed coil may be
provided and assembled with the core pieces 182 to complete the
inductor component. The PC core configuration 180 in the example
shown generally has a volume that is a function of Window Area (WA)
where the coil is applied, Mean Length Per Turn (MLT) for the coil,
and Cross-sectional Area (AC). FIG. 8B shows a Window Area 184 and
a Cross-sectional Area 186 associated with the coil is shown in
FIG. 8A.
[0085] An inductor component including the PC core configuration
180 shown in FIGS. 8A, 8B and 8C 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 180 may be through-hole mounted to a
circuit board. In some embodiments, the winding formed on the core
180 need not connect to a circuit board at all, but rather may be
terminated to external circuitry using known connections and
techniques.
[0086] FIGS. 9A, 9B and 9C depict an exemplary DS core
configuration 190 in plan view (FIG. 9B) and including first and
second core pieces 192 that are identically shaped but assembled in
a reverse or mirror-image arrangement with respect to one another.
The core pieces 192 may be fabricated from magnetic materials such
as those described above. The DS core configuration 190 is shown in
cross section in FIG. 9A and the core piece 192 is shown in
perspective view (FIG. 9C). The DS core configuration 190 may be
utilized in accordance with an exemplary embodiment of the
invention when a composite, ultra-conductive wire (not shown in
FIGS. 9A, 9B, 9C) is wound on the surface of the EPC core
configuration 190 to complete a coil in a known manner and provide
an inductor component. Alternatively, a pre-formed coil may be
provided and assembled with the core pieces 192 to complete the
inductor component. The DS core configuration 190 in the example
shown generally has a volume that is a function of Window Area (WA)
where the coil is applied, Mean Length Per Turn (MLT) for the coil,
and Cross-sectional Area (AC). FIG. 9B shows a Window Area 194 and
a Cross-sectional Area 196 associated with the coil is shown in
FIG. 9A.
[0087] An inductor component including the DS core configuration
190 shown in FIGS. 9A, 9B and 9C 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 190 may be through-hole mounted to a
circuit board. In some embodiments, the winding formed on the core
190 need not connect to a circuit board at all, but rather may be
terminated to external circuitry using known connections and
techniques.
[0088] FIGS. 10A and 10B depicts an exemplary inductor component
200 including an I core 202 and a coil 204 fabricated from an
ultra-conductive material such as that described above. The I core
202 may be fabricated from magnetic materials such as those
described above. The composite, ultra-conductive wire is wound on
the surface of the I core 202 for a number of turns to complete the
coil 204. Alternatively, the coil 204 may be pre-formed and
provided for assembly with the I core 202 to complete the inductor
component 200. The I core 202 in the example shown generally has a
volume that is a function of Window Area (WA) where the coil is
applied, Mean Length Per Turn (MLT) for the coil, and
Cross-sectional Area (AC). FIG. 10B shows a Window Area 206 and a
Cross-sectional Area 208 associated with the coil 204 is shown in
FIG. 10A.
[0089] 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.
[0090] FIGS. 11-13 depict Mean Length Per Turn (MLT) of various
types of coil/winding geometries. The coil geometries shown can be
used in combination with one or more of the core structures
discussed above or with still other core structures in various
embodiments.
[0091] FIG. 11 depicts a coil 210 fabricated from an
ultra-conductive composite material and formed into a winding. The
winding has an exemplary Mean Length Per Turn indicated by the
hyphenated line and the reference character 212. In the example
shown, the winding formed in the coil 210 includes seven full
turns. As used herein a "turn" shall refer to a portion of a
conductive path defined in the coil 210 that completes one full
revolution of the conductive path in a loop. In the illustrated
example, each turn, sometimes referred to as a loop, has a
beginning and an end and has a generally rectangular shape with
rounded corners. Where one turn ends the next turn begins, and the
conductive paths repeat in a continuous fashion in the coil in the
multiple turn configuration illustrated. As noted above, in general
the greater number of turns that are provided in the winding 210,
the greater inductance value for a component including the winding
210. Likewise, the fewer number of turns provided in the coil 210,
the lesser the inductance value for a component including the coil
210. While seven turns are illustrated in the example shown in FIG.
11, greater or lesser values, including fractional values (e.g., 7
1/2 or 7.5) turns are possible.
[0092] FIG. 12 depicts a C-shaped coil 220 defining a winding
resembling those shown in FIGS. 1 and 2 that is fabricated from an
ultra-conductive composite material and having an exemplary Mean
Length Per Turn indicated by the hyphenated line and the reference
character 222. It is seen in example of FIG. 12 that the winding of
the coil 220 completes less than one full turn of a winding. When
used in a surface mount component such as those shown in FIGS. 1
and 2, additional partial turns may be provided on the layout of
the circuit board, such that when the coil 220 is connected to the
partial turn on the circuit board, an increased number of turns is
provided in the combination.
[0093] FIG. 13 depicts a multiple layer coil 230 that is fabricated
from an ultra-conductive composite material. The coil 230 has a
winding geometry including a first outer winding layer 232 and a
second inner layer 234. The first layer 232 has an exemplary Mean
Length Per Turn indicated by the hyphenated line and the reference
character 236. The second layer 234 has an exemplary Mean Length
Per Turn indicated by the hyphenated line and the reference
character 240. Multiple turns can be provided in each of the first
and second winding layers 232, 234.
[0094] It is understood that the core and coil configurations in
the examples of FIGS. 1-13 are non-limiting and other core types
and coil geometries can be utilized as desired without departing
from the spirit of the invention. In some embodiments, coils may be
deposited on a substrate layer and a winding pattern created on the
substrate. Various patterns, shapes, or geometries of coil windings
are possible including but not limited to spiral and serpentine
winding shapes. Where multiple coils are provided, the coils may be
overlapped with one another or spaced apart from one another.
[0095] 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.
[0096] Referring to FIG. 14, there is shown a coil 250 fabricated
from a composite ultra-conductive conductor material and wound for
a number of turns to complete a winding. As seen in FIG. 14 at one
end of the coil 250, the conductor has a round or circular cross
section including a diameter D.sub.1. The diameter D.sub.1 of the
round wire may vary in different embodiments, and the cross
sectional area of the conductor likewise varies with the selected
diameter D.sub.1. As mentioned above, the cross sectional area of
the coil, in part, determines the inductance value of a component
including the coil 250.
[0097] FIG. 15 illustrates a coil 260 also fabricated from a
composite ultra-conductive conductor material and wound for a
number of turns to complete a winding. As seen in FIG. 15 at one
end of the coil 260, the conductor has a rectangular cross section
including a major dimension D.sub.2. The conductor shown in the
coil 260 is sometimes referred to as a flat wire coil, whereas the
conductor shown in the coil 250 (FIG. 14) is referred to as a round
wire coil. The dimension D.sub.2 of the flat wire may vary in
different embodiments, and the cross sectional area of the
conductor likewise varies with the selected dimension D.sub.2. As
mentioned above, the cross sectional area of the coil, in part,
determines the inductance value of a component including the coil
260.
[0098] If a coil wire has cross-sectional shape other than round,
as shown in the example of FIG. 15, its effective "diameter" for
purposes of the present invention shall be deemed to be the
diameter of a round wire with equivalent cross-sectional area. As
one example, if the major dimension D.sub.2 has a value (e.g., 6 in
a unit length) in a given embodiment, and the minor dimension
measured in a direction perpendicular to the major dimension
D.sub.2 in FIG. 15 has a value (e.g., 2 in the same unit length),
the cross sectional area of the conductor is the product of these
two values or 12 square units. A diameter of a circular cross
section having the same 12 square units in cross sectional area can
be computed by first finding the radius of a circular cross section
using the following relationship for a circular cross section:
A=.pi.r.sup.2
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.times.2) or 3.9. The conductor shown in FIG. 15
having a rectangular cross sectional area of 12 square therefore
has an "effective diameter" of 3.9 for purposes of the present
invention.
[0099] FIG. 16 shows additional cross sectional areas of
ultra-conductive composite conductor materials that may be utilized
to fabricate windings of a coil in electromagnetic components
according to the present invention. In the examples shown in FIG.
16, the cross sections may be square as shown in the example
conductor 290, round or circular as shown in the example conductor
300, multifillar as shown in the example conductor 302, rectangular
as shown in the example conductor 304, a high aspect ratio cross
section as shown in the example conductor 306, and a cooled cross
section as shown in the example conductor 308. For each of these
cross sections of conductors, an "effective diameter" can be
computed in a similar manner to the example above. In the case of a
round cross section such as in the conductor 300, the effective
diameter is equal to the actual diameter of the round
conductor.
[0100] Of course, the exemplary conductors and cross sections
illustrated in FIG. 16 are exemplary only. Other conductors and
cross sectional configurations are possible to construct coils for
electromagnet inductor components in further and/or alternative
embodiments of the invention. Coils may fabricated from such
conductors to include any number of turns and/or arrangement of
turns or layers. In multiple turn embodiments, a plurality of turns
may be arranged concentrically with or without insulation in
between. A plurality of coils may further be provided and may be
electrically connected in series or in parallel. A plurality of
coils may be arranged in a flux sharing relationship so that the
coils are mutually coupled, or a plurality of uncoupled coils may
be independently operable but nonetheless coupled to a common
magnetic core structure.
[0101] FIG. 17 illustrates a conductor 270 that may be fabricated
from ultra-conductive composite materials and wherein multiple
conductor strands are combined and twisted about one another to
form a larger conductor 270. The conductor 270 may be provided as a
length of wire that in turn may be wound for a number of turns to
complete a coil having a mean length per turn (MLT) as discussed
above. The example conductor 270 shown in FIG. 17 may be recognized
as resembling a Litz wire or magnet wire, and the cross sectional
area of the conductor 270 is equal to the sum of the cross
sectional areas of the conductor strands. As such, in the
illustrated example, seven conductor strands are utilized having
the same circular cross sectional area, so the cross sectional area
of the entire conductor is seven times the cross sectional area of
the strands utilized. 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 270.
[0102] 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.times.2) or 4.22. The
conductor shown in FIG. 17 having a cross sectional are of 14
square units therefore has an "effective diameter" of 4.22 for
purposes of the present invention.
[0103] FIG. 18 illustrates a conductor 280 that may be fabricated
from ultra-conductive composite materials and wherein multiple
conductor strands are combined and twisted about one another to
form a larger conductor 280. The conductor 280 may in turn be wound
for a number of turns to complete a winding in a coil having a mean
length per turn (MLT) as discussed above. The example conductor 280
shown in FIG. 18 may be recognized as a combination of conductors
such as that shown in FIG. 17, and the cross sectional area of the
conductor 280 is equal to the sum of the cross sectional areas of
the conductors 270. As such, in the illustrated example, seven
conductors 270 are utilized to fabricate the conductor 280.
[0104] 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.times.2) or 11.18. The conductor 280 shown in FIG. 18 having a
cross sectional are of 98 square units therefore has an "effective
diameter" of 11.18 for purposes of the present invention.
[0105] 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/.beta.).sup.1/2
where .beta. 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 (.beta.) 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.
[0106] 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 FIGS. 1 and 2 and inductors fabricated
from the other core structures and coil configurations described
above. Of course, if the effective diameter of the coil conductor
may be reduced by virtue of greater conductivity of composite
conductive materials, and the number of turns can also be reduced,
even more significant size reductions in electromagnetic components
such as inductors is possible.
[0107] 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.
[0108] 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 (.beta.) 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 (.delta.) in the rest of description.
Further, for a given value of diameter ratio (.delta.) and
conductivity ratio (.beta.) 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
(I.sub.SAT), 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.
[0109] In accordance with embodiments of the present invention, if
the conductivity of composite material used in the coil conductor
is .beta. times that of a reference copper conductor of the
reference inductor, then the diameter ratio (.delta.) may be
adjusted within a range of 1 to .beta..sup.-1/2. In one example,
within a sub-range (1 to .beta..sup.-1/4) of the entire range 1 to
(1/.beta.).sup.1/2, by keeping the saturation current (I.sub.SAT)
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
(.mu.) can be adjusted to obtain desired values. The desired values
of Inductance (L), DC Resistance (DCR), Core Volume (V), effective
permeability of the core (.mu.), and number of turns (N) in the
winding are adjustable within regions having upper limits defined
by functions (.delta..sup.-2), [.beta..sup.(-1)*.delta..sup.(-4)],
1, .beta..sup.2/3, .delta..sup.(-2) and lower limits defined by
functions 1, [.beta..sup.(-1)*.delta..sup.(-2)], (.delta..sup.2),
(.delta..sup.2), (.delta..sup.(-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.
[0110] The limits and functions referred to above are derived from
relationships illustrated in graphical form in FIG. 19. In FIG. 19,
the diameter ratio (.delta.) is plotted along the x-axis. Since the
conductivity ratio (.beta.) relates to the diameter ratio
(.delta.), the values of the diameter ratio (.delta.) are shown in
reference to a function of the conductivity ratio (.beta.).
Exemplary component parameters are plotted along the y-axis as
functions of the diameter ratio (.delta.).
[0111] FIG. 19 shows a first bounded region of performance
improvement in terms of inductance 401 as a function of diameter
ratio (.delta.) that may be utilized in the inductor design and
fabrication approach of the present invention. The region 401 shown
in FIG. 19 is shown to be bounded by broken lines that are
respectively derived from theoretical relationships and computation
using the variables (.beta.) and (.delta.), and as shown in FIG. 19
the region 401 is defined by an upper boundary value defined by the
function .delta..sup.(-2) and a lower boundary value of 1. It is
apparent that a desired value of diameter ratio (.delta.) for an
inductor component of the present invention can be any value within
these boundaries to provide an inductor having an increased
inductance value (or the same inductance value if the conductivity
ratio (.beta.) is nearly 1) as the reference inductor.
[0112] However, if the diameter ratio (.delta.) 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 (.beta.) and (.delta.) is the same or
better in terms of its inductance value than the inductance value
of the reference inductor.
[0113] Similarly, additional bounded design improvement regions
403, 405, 407, and 409 are shown in FIG. 19 showing respective
regions of performance improvement in terms of direct current
resistance (DCR), Core Volume (V), number of turns (N) of the
winding, and effective permeability (.mu.). The bounded regions
403, 405, 407, and 409 shown in FIG. 19 are derived from
theoretical relationships and computation using the variables
(.beta.) and (.delta.). It is apparent that a desired value of
diameter ratio (.delta.) (which relates to the conductivity ratio
(.beta.)) can be any value within these bounded regions 403, 405,
407, and 409 to provide an inductor of the present invention having
improved values relative to the reference inductor. If the diameter
ratio (.delta.) is selected to be outside the boundaries of the
respective bounded regions 403, 405, 407, and 409 shown, the
resultant component including the higher conductivity composite
material will not be improved relative to the reference inductor
for the respective parameters of direct current resistance (DCR),
Core Volume (V), number of turns (N) of the winding, and effective
permeability (.mu.). Again, such results are perhaps
counterintuitive and are preferably avoided. The bounded regions
401, 403, 405, 407, and 409 provide a range of values between and
including the boundary lines, within the limits shown in which the
inductance value of a component of the invention constructed with
values (.beta.) and (.delta.) is the same or better in terms of its
inductance value than the reference inductor.
[0114] The reader may recognize that the bounded regions 401, 403,
405, 407, and 409 shown in FIG. 19 may be superimposed to define
still other regions wherein, if values of the diameter ratio
(.delta.) are selected within those regions, more than one of the
parameters for each respective region shown will be improved
relative to the reference inductor. Using such bounded regions,
inductor performance in an inductor of the present invention may be
substantially optimized with respect to multiple performance
parameters in reference to the reference inductor. Alternatively
stated, inductor components may be constructed that simultaneously
offer improved performance relative to the reference inductor
across multiple parameters. Equal or better performance across
various combinations of parameters is facilitated as described
further below in relation to contemplated examples.
[0115] In accordance with contemplated embodiments of the present
invention, within a sub-range (.beta..sup.-1/4 to .beta..sup.-1/2)
of the entire range 1-(1/.beta.).sup.1/2 of the diameter ratio
(.delta.) shown in FIG. 19, by keeping the saturation current
(I.sub.SAT) 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 winding, and effective
permeability (.mu.) can be adjusted to obtain desired values. The
desired values of Inductance (L), DC Resistance (DCR), Core Volume
(V), effective permeability of the core (.mu.), and number of turns
(N) are adjustable as shown in FIG. 19 within respective bounded
regions 421, 423, 425, 427 and 429 shown with respective broken
lines and having upper limit values defined by respective functions
[.beta.*.delta..sup.2], 1, [.beta.*.delta..sup.(4)],
.delta..sup.2/3, [.beta..sup.(2/3)*.delta..sup.(2/3)] and lower
limit values defined by respective functions 1,
[.beta..sup.(-1)*.delta..sup.(-2)], (.delta..sup.2),
[.beta..sup.(-2/3)*.delta..sup.(-2/3)], (.delta..sup.(-2/3)). It
must be noted that the bounded regions of improvement shown,
wherein the desired values can be adjusted to achieve different
ranges of performance with respect to the parameters illustrated,
are envisaged in relation to respective values of the same
reference parameters.
[0116] Referring still to FIG. 19, within the bounded regions 403
and 423, the DC Resistance (DCR) appears to be increasing with
decreasing effective diameter shown on the x-axis. It must be
appreciated, however, that when the effective diameter of a
conductor fabricated from composite conductive material having
improved conductivity as explained earlier (relating to the
diameter ratio (.delta.)) decreases in comparison to that of the
reference inductor, the DC Resistance (DCR) never exceeds that of
the reference inductor (which is considered to be 1 in this
example). Therefore, DC Resistance (DCR) of the component of the
invention still remains lower than the reference inductor and
offers performance improvements in other parameters such as core
volume, inductance, etc.
[0117] 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).
[0118] 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 FIG. 19 and the height of
the Window Area (WA) will be adjustable within the same region of
values as Core Volume shown in FIG. 19. However, there will be an
impact on the number of turns (N) and effective permeability (.mu.)
as explained in the following paragraphs and illustrated in
relation to FIGS. 31-35.
[0119] As seen in FIGS. 31-35, for a diameter ratio (.delta.) in
the sub-range (1 to .beta..sup.-1/4) of the entire range
(1-(1/.beta.).sup.1/2) shown in FIG. 19 and at the saturation
current (I.sub.SAT) equal to the saturation current of the
reference inductor, the number of turns (N) in the coil winding and
effective permeability (.mu.) of the core have a different region
of performance improvement than indicated in FIG. 19, where the
desired values of these parameters can be obtained. The desired
values of effective permeability of the core (.mu.), and number of
turns (N) are adjustable within regions having upper limit values
defined by functions 1, [.delta..sup.(-2)] and lower limit values
defined by functions [.delta..sup.(2)], 1, respectively.
[0120] Similarly, and as also illustrated in FIGS. 31-35, for
diameter ratio (.delta.) within the sub-range (.beta..sup.-1/4 to
.beta..sup.-1/2) of the entire range 1-(1/.beta.).sup.1/2 and at
the saturation current (I.sub.SAT) equal to the reference
saturation current, the desired values of the effective
permeability of the core (.mu.), and number of turns (N) can be
adjusted in different bounded regions. The desired values of
effective permeability of the core (.mu.), and number of turns of
(N) in the winding are adjustable within bounded regions having
upper limits defined by functions 1, [.beta.*.delta..sup.(2)] and
lower limits defined by functions
[.beta..sup.(-1)*.delta..sup.(-2)], 1, respectively.
[0121] FIG. 20 shows a bounded region of performance improvement
502, 522 in terms of effective permeability of the core defined
with a first set of broken lines, and bounded regions of
performance improvement 504, 524 in terms of the number of turns of
coil wire shown with a second set of broken lines for two different
diameter sub-ranges mentioned above. It should be understood that
these bounded regions shown in FIG. 20, and also FIGS. 34-35, are
different than the bounded regions when variation in core volume
happens proportionally for all dimensions.
[0122] As illustrated in FIG. 21, the proposed invention improves
the overall performance of an exemplary inductor component
according to the invention in relation to a reference inductor,
where by using coil wire made of composite material having carbon
nanotubes and by keeping fixed at least one of the parameters of
the inductor in relation to the reference inductor, other
parameters can be improved. The technical advantages of the
invention in terms of overall size reduction is apparent in FIG.
21, where the inductor 603 of the invention including the higher
conductivity composite material coil wire is dimensionally much
smaller than the reference inductor 601 which has conventional coil
wire made of copper. Reductions in size are likewise possible
utilizing any of the other core structures and coil configurations
described above.
[0123] Referring to FIG. 22, there is shown a table representing
inductor component improvements for a set of inductors in terms of
DC Resistance (DCR), Inductance (L), for a fixed value of
Saturation current I.sub.SAT and core size when higher conductivity
composite conductive material is used to fabricate the coil/winding
in the inductor. In the examples shown, a composite conductive
material having a conductivity that is twice the conductivity of
copper is assessed to evaluate possible performance improvements.
That is, the examples shown in FIG. 22 demonstrate the benefits of
utilizing a composite conductive material having a conductivity
ratio (.beta.) of 2. As the preceding description makes clear,
however, other conductivity ratios (.beta.) are possible and may
likewise be beneficially used with different results than that
shown.
[0124] In the table of FIG. 22, the first column 700 tabulates
attributes of a number of conventionally formed inductor components
identified by part number at the left-hand side. In the example
shown, a number of Coiltronic SD3110 Series Low Profile Power
Inductors are shown having different ratings. Such inductors are
commercially available from Eaton Electronics (www.Eaton.com)
(formerly Cooper Bussmann Electronics) and have a known
configuration. The low profile SD3110 Series power inductors may be
utilized in exemplary, non-limiting applications such as cellular
phones, digital cameras, compact disc players, media player
devices, personal digital assistant (PDA) devices, liquid crystal
displays, light emitting diode (LED) driver and flash circuits,
hard disk drives, backlighting, and electroluminescent (EL) panels.
Further, the SD3110 Series power inductors are miniaturized
components including surface mount terminations for circuit board
applications. The SD3110 Series power inductors have a package size
of 3.1 mm by 3.11 mm by 1.0 mm.
[0125] Inductance values (L), saturation current values
(I.sub.SAT), 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.
[0126] The second column 702 shown in the Table of FIG. 22 includes
corresponding attributes of a first set of inductor components
formed in accordance with the present invention, but in reference
to the SD3110 Series power inductor components tabulated in the
first column 700. The corresponding values of the first set of
inductor components formed in accordance with the present invention
are calculated according to the teachings above and tabulated in
the column 702. Comparing the rows of the columns 700 and 702, it
is seen that the inductor components are provided in the first set
of components in the column 702 have the same inductance values as
the reference inductors tabulated in the column 700 and also the
same (I.sub.SAT) values as the reference inductors tabulated in the
column 700. The first set of inductors shown in the column 702,
however, have a 50% reduction in DCR values relative to the
reference inductors tabulated in the column 700.
[0127] 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
(.delta.) has been selected to equal 1). The effective permeability
value (.mu.) 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.
[0128] The third column 704 shown in the Table of FIG. 22 tabulates
calculated values of a second set of inductor components formed in
accordance with the present invention. Comparing the rows of
columns 700 and 704, it is seen that the inductor components of the
second set shown in the column 704 have significantly greater
(about 50% greater in the embodiments tabulated) inductance values
than the reference inductors (e.g., the SD3110 Series power
inductors) that are tabulated in the column 700, while maintaining
the same (I.sub.SAT) values as tabulated in the column 700, and the
same DCR values relative to those tabulated in tabulated in the
column 700. As seen at the bottom of the third column 704, these
results for the second set are obtained using an effective diameter
conductor that is 84% of the effective diameter of the reference
inductors in the column 700. The air gap in the second set of
components is enlarged to provide an effective permeability value
(.mu.) of 0.707. The reduction in effective diameter allows the air
gap to be enlarged while maintaining the same package size as the
reference SD3110 Series power inductors shown in the column
700.
[0129] The fourth column 706 shown in the Table of FIG. 22
tabulates calculated values of a third set of inductor components
formed in accordance with the present invention. Comparing the rows
of columns 700 and 706, it is seen that inductor components in the
third set of column 706 have a significantly greater (about 23%
greater in the embodiments tabulated) inductance values than the
reference inductors tabulated in the column 700, the same
(I.sub.SAT) values as tabulated in the column 700, and
significantly reduced DCR values (about 30% less) relative to those
tabulated in the column 700 for the reference inductors. As seen at
the bottom of the fourth column 706, these results are obtained
using an effective diameter conductor that is 90% of the effective
diameter of the reference inductors in the column 700, and a larger
air gap is provided to provide an effective permeability value
(.mu.) of 0.81.
[0130] The findings in the Table of FIG. 22 corroborate the bounded
regions shown in FIG. 19. It is believed that similar results could
be generated for other sets of reference inductors. It should now
be evident from the results of FIG. 22 that improved inductors can
be provided having the same package size with improved performance
to the reference inductors, smaller package size with the same
performance as the reference inductors, and various combinations of
package sizes and different performance parameters that are not
believed to be possible with the reference inductor including
copper coils and windings.
[0131] FIG. 23 illustrates an exemplary flowchart of a method 650
of manufacturing electromagnetic inductor components in accordance
with exemplary embodiments of the present invention.
[0132] 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 FIG. 22 and discussed
above.
[0133] 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.
[0134] At step 656 a ratio is determined of electrical conductivity
(.beta.) 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.
[0135] As shown at step 658, improvement regions such as those
shown in FIGS. 19 and 20 may be provided. The regions, as explained
above, may be derived from theoretical relationships and
computation. The regions may be provided as a preparatory step to
the method 650 or may be determined as part of the method and
provided for reference in the fabrication of an electromagnetic
inductor component including the material provided at step 654. The
regions may be developed for each respective inductor component
parameter such as those described in the embodiments above. The
regions may be defined for each parameter of interest to include
functions of the ratio of electrical conductivity (.beta.)
discussed above, which also relates to the effective diameter ratio
(.delta.) as described above. The regions of values may be defined
by a function of the ratio of electrical conductivity (.beta.) and
the effective diameter ratio (.delta.) as described above. It is
understood that graphs such as those in FIGS. 19 and 20 may be
helpful to do this, but are not strictly necessary for the
improvement regions to be defined and utilized.
[0136] 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
(.beta.). 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.
[0137] 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.
[0138] 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.
[0139] 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 (I.sub.SAT) for the component design
including the composite conductive material may be selected to
match the saturation current (I.sub.SAT) 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.
[0140] In at least some contemplated embodiments, and as shown in
phantom in FIG. 23, the step 666 may optionally be performed prior
to step 658. In such embodiments, the improvement regions provided
at step 658 may be generated in view of the selected performance
parameter at step 666. For example, if the saturation current is
selected at step 666 in accordance with the examples described
herein, the improvement regions and graphs described above may
result. However, if another performance parameter or characteristic
of the reference inductor is selected to match the reference
inductor at step 666, the resultant improvement graphs and regions
will be different from those illustrated described herein. As such,
the design improvement regions described and illustrated herein are
provided for discussion purposes only and are not required to
practice the inductor design methodology and fabrication techniques
of the invention to manufacture improved inductor component having
the higher conductivity composite material.
[0141] 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 FIG. 23. For
example, if multiple sets of improvement regions and graphs are
pre-generated and made available to an inductor designer or
fabricator, the selection at step 666 may be made at any time
subsequent to the generation of the improvement regions and graphs.
Once the selection at step 666 is made, the applicable one of the
sets of improvement regions and graphs may be consulted. A catalog
of different improvement regions and graphs may be consulted to
facilitate a full range of design possibilities and aid in the
understanding of how certain selections may affect the inductor
component as a whole in various different aspects. Such an approach
may identify designs that may be unsatisfactory without even having
to specifically analyze them, build them or test them, and
inductors and designers may instead focus on more promising designs
as evidenced by the improvement regions and graphs. In other words,
in some cases the improvement regions and graphs provided at step
658 may serve as a guide to which selection should be made at step
666 to provide an optimal inductor of the present invention.
[0142] 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 (I.sub.SAT) value being selected at step 666, another
parameter (besides the (I.sub.SAT) 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 ((I.sub.SAT) 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.
[0143] Following the example above, if the (I.sub.SAT) 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.
[0144] 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 I.sub.SAT 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 (.mu.) 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 I.sub.SAT 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.
[0145] 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.
[0146] 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.
[0147] 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.
[0148] FIGS. 24-35 more specifically illustrate various examples of
electromagnetic component design and fabrication techniques
utilizing the methodology described above.
[0149] FIG. 24 is an exemplary design improvement region graph
similar to FIG. 19 that may be utilized in the method of FIG. 23 to
achieve different points of possible improvement for an
electromagnetic inductor component of the present invention
including improved conductivity composite material. FIG. 24
generally shows that for any given value of effective diameter
ratio (.delta.), represented in FIG. 24 by the vertical line 700,
different parameter values can be selected to achieve different
performance characteristics or objectives in the inductor component
design and fabrication of the invention.
[0150] More specifically, a first exemplary set of points 702,
represented by circles in FIG. 24, may be utilized to construct a
first embodiment of an inductor component according to the
invention including improved conductivity composite material and a
core size the same as the reference inductor, a maximum improved
inductance value relative to the reference inductor, and improved
direct current resistance relative to the reference inductor.
[0151] A second exemplary set of points 704, represented by squares
in FIG. 24, is also shown. The second set of points 704 may be
utilized to construct a second embodiment of an inductor component
according to the invention including improved conductivity
composite material and having a reduced core size relative the
reference inductor, an increased inductance value relative to the
reference inductor, and reduced direct current resistance relative
to the reference inductor.
[0152] A third exemplary set of points 706 is shown in FIG. 24 and
represented by diamonds. The third set of points 706 may be
utilized to construct a third embodiment of an inductor component
according to the invention including improved conductivity
composite material and having a minimal core size relative to the
reference inductor, the same inductance value as the reference
inductor, and reduced direct current resistance relative to the
reference inductor.
[0153] 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 (.delta.) values that may be selected to
defines lines other than the line 700 shown in FIG. 24 from which
corresponding points may be selected, including but not limited to
a line that passes through the regions 421, 423 and 425 instead of
the regions 401, 403 and 405 as shown in the example of FIG.
24.
[0154] 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 FIG. 24 from left to right, the inductance
value L of a component according to the invention along any given
line 700 increases from a value of 1 as the effective diameter
ratio (.delta.) increases within the region 421 to its maximum
value shown as the regions 421 meets the region 401, and then
decreases in the region 401 from the maximum shown to a value of 1
that is again equal to the inductance value of the reference
inductor.
[0155] It should now be appreciated that FIG. 24 graphically
depicts a large number of possible inductor component design
selections, represented here for discussion purposes as points
along the line that fall within the bounded improvement regions,
according to the invention. Inductor components including improved
conductivity composite material constructed in accordance with
selected points will exhibit the same or better characteristics of
the reference inductor in the parameters illustrated. Once the
regions 401, 403 and 405 are defined in a manner such as that shown
in the example of FIG. 24 as a function of effective diameter ratio
(.delta.), a range of inductor components according to the
invention may be design and their characteristics may be readily be
appreciated without intensive analysis, computation, or trial and
error that traditional design processes would typically entail.
[0156] FIG. 25 is a magnified view of a portion of FIG. 24 showing
the first set of points 702 selected for the (.delta.) value
represented in by the exemplary vertical line 700 shown in the
illustrated example. Assuming in the example of FIG. 25 that the
inductor component design is desired to have the same saturation
current value as the reference inductor, a maximum inductance value
(i.e., the highest L value in the bounded region 401) for the
selected (.delta.) value at step 662 (represented by the vertical
line 700) may be selected for purposes of step 668. The highest L
value for the selected (.delta.) value is seen at the top of FIG.
25. Because the saturation current value (step 666) and the
inductance value (step 668) are now selected in this example, the
DCR value and V value are now determined in the regions 403 and 405
and are required for use to construct an inductor according to the
present invention including improved conductivity composite
material. As such, the DCR value 702 in the region 403 and the V
value 702 in the region 405 are each accepted per step 670 for the
selected (.delta.) value at step 662 (represented by the vertical
line 700).
[0157] Alternatively, as should be evident from FIG. 25, other
points, including but not limited to the points 704 and 706
discussed above, may be selected along the line within the regions
401, 403, 405 in the example illustrated. Selection of such other
points will produce an inductor component according to the
invention including improved conductivity composite material but
having an inductance value L that is less than the maximum point
discussed above. Once again and following the example above, once
the saturation current value (step 666) and an inductance value
corresponding to either point 704 or 706 (step 668) are selected,
the corresponding DCR values and V values for the selected point
704, 706 are now determined in the regions 403 and 405 and are
required for use to construct an inductor according to the present
invention including improved conductivity composite material.
[0158] As shown in FIG. 26, the number of turns value 702 in the
region 409 and the effective permeability value 702 in the region
407 are also now determined and required for use by virtue of the
prior selection of the saturation current value (step 666) and the
inductance value (step 668). The number of turns value and the
effective permeability value are each accepted per step 670 for the
selected (.delta.) value at step 662 (represented by the vertical
line 700).
[0159] Once the appropriate selections are made, as represented by
the lines and points discussed above in relation to FIGS. 24 and
25, the inductor component according to the invention can then be
constructed per steps 674, 676 and 678 to achieve parameters
corresponding, for example only, to the points 702 shown in FIGS.
25, 26 and 27. The inventive inductor components constructed using
the points 702 will have the same core size (and shape) as the
reference inductor, a maximum improved inductance value relative to
the reference inductor for the selected (.delta.) value, and
improved direct current resistance relative to the reference
inductor.
[0160] FIG. 27 is a magnified view of a portion of FIG. 24 showing
the second set of points 702 selected for the (.delta.) value
represented by the vertical line 700. Assuming in the example of
FIG. 27 that the component design is desired to have the same
saturation current value as the reference inductor, an improved
(but not maximum) L value 704 in the bounded region 401 for the
selected (.delta.) value at step 662 (represented by the vertical
line 700) may be selected for purposes of step 668. Because the
saturation current value (step 666) and the inductance value 704
(step 668) are now selected in this example, the DCR value and V
value are now determined and required for use. As such, the DCR
value 704 in the region 403 and the V value 704 in the region 405
are each accepted per step 670 for the selected (.delta.) value at
step 662 (represented by the vertical line 700).
[0161] As shown in FIG. 28, the number of turns value 704 in the
region 409 and the effective permeability value 704 in the region
407 are also now determined and required for use by virtue of the
prior selection of the saturation current value (step 666) and the
inductance value (step 668). The number of turns value and the
effective permeability value are each accepted per step 670 for the
selected (.delta.) value at step 662 (represented by the vertical
line 700).
[0162] 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 FIGS. 27 and 28. The
inventive inductor component constructed will have improved
inductance, direct current resistance and core size relative to the
reference inductor. The core size in the completed inductor of the
invention is proportionally reduced in all dimensions as explained
above, without changing the overall shape of the core relative to
the reference inductor,
[0163] FIG. 29 is a magnified view of a portion of FIG. 24 showing
the third set of points 706 selected for the (.delta.) value
represented by the vertical line 700. Assuming in the example of
FIG. 29 that the inductor component design according to the
invention including improved conductivity composite material is
desired to have the same saturation current value as the reference
inductor, the minimum DCR value 706 in the bounded region 403 for
the selected (.delta.) value at step 662 (represented by the
vertical line 700) may be selected for purposes of step 668.
Because the saturation current value (step 666) and the DCR value
706 (step 668) are now selected in this example, the inductance
value L and V value are now determined and required for use to
construct an inductor according to the invention including improved
conductivity composite material. As such, the L value 706 in the
region 401 and the V value 706 in the region 405 are each accepted
per step 670 for the selected (.delta.) value at step 662
(represented by the vertical line 700).
[0164] As shown in FIG. 30, the number of turns value 706 in the
region 409 and the effective permeability value 706 in the region
407 are also now determined and required for use by virtue of the
prior selection of the saturation current value (step 666) and the
DCR value (step 668). The number of turns value and the effective
permeability value are each accepted per step 670 for the selected
(.delta.) value at step 662 (represented by the vertical line
700).
[0165] 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 FIGS. 29 and 30. The inventive inductor
component constructed will have the minimum direct current
resistance, the same inductance value as the reference inductor,
and a minimum core size relative to the reference inductor. The
core size in the completed inductor of the invention is
proportionally reduced, without changing the shape of the core
relative to the reference inductor,
[0166] FIGS. 31-35 illustrates still aspects of an inductor
component design according to the invention including improved
conductivity composite material. In these figures, only one of the
dimensions of the core of the inventive inductor component, namely
the height dimension, is reduced while the remaining dimensions
(length and width) remain the same. As such, the inventive inductor
component may have the same footprint area as the reference
inductor, but with a reduced component height. Lower profile
inductors according to invention are therefore realized with
improved performance relative to reference inductors, but having
the same footprint for circuit board applications.
[0167] The methodology illustrated in the relation to the exemplary
graphs of FIGS. 31-35 may be particularly beneficial for improving
so-called families of components that may be used as reference
inductors. For discussion purposes, a "family" as used herein shall
refer to a set of inductor components having a common design
structure (e.g., the same magnetic core structure fabricated from
the same magnetic material(s) and having the same coil
configuration fabricated from the same conductive material).
Additionally, each of the set of components in a "family" typically
has the same "footprint" as defined above in paragraph [0004] but
has one of a plurality of different ratings, such that the family
can collectively meet the needs of various different applications
while still providing economies of scale in the inductor
manufacture. The methodology herein may be particularly useful in
providing such families with equal footprint, but lower "profile"
(i.e., a reduced height dimension) of inductor components to
facilitate the trend of smaller electronic devices in the
corresponding dimension and meet needs that are difficult, if not
impossible, to fulfill using convention inductor design and
fabrication techniques utilizing conventional copper materials
having a lower conductivity than the composite materials described
herein.
[0168] FIG. 31 illustrates a first improvement region in graphical
form for an inductor component or family of components according to
the present invention including improved conductivity composite
material. Specifically, FIG. 31 indicates the bounded inductance
value L regions 401 and 421 as described above. A range of
(.delta.) values are plotted along the x-axis with a range of
inductor values plotted along the y-axis.
[0169] FIG. 32 illustrates a second improvement region in graphical
form for an inductor component or family of components according to
the present invention including improved conductivity composite
material. Specifically, FIG. 32 indicates the bounded DCR value
regions 403 and 423 as described above. A range of (.delta.) values
are plotted along the x-axis with a range of DCR values plotted
along the y-axis.
[0170] FIG. 33 illustrates a third improvement region in graphical
form for an inductor component or family of components according to
the present invention including improved conductivity composite
material. Specifically, FIG. 33 indicates the bounded core size V
value regions 405 and 425 as described above. A range of (.delta.)
values are plotted along the x-axis with a range of V values
plotted along the y-axis. Because in the example of FIG. 33 the
core area or footprint of the inventive inductor component is
constant (i.e., the same as the reference component), only the
height dimension of the an inductor component according to the
present invention including improved conductivity composite
material can actually be varied relative to the reference component
and is reflected in the values of the y-axis.
[0171] FIG. 34 illustrates a fourth improvement region in graphical
form for an inductor component or family of components according to
the present invention including improved conductivity composite
material. Specifically, FIG. 34 indicates the required number of
turns value (N) regions. A range of (.delta.) values are plotted
along the x-axis with a range of inductor values plotted along the
y-axis. For the reasons explained earlier, the required number of
turns values N in FIG. 34 does not correspond to the regions 409,
429 as shown and described in relation to FIG. 19. As such, for any
given value of (.delta.), the upper and lower limits of the bounded
region shown in FIG. 34 is different than the regions 409 and 429
that apply to cases wherein the core size is proportionally varied
in all dimensions without otherwise changing the shape.
[0172] FIG. 35 illustrates a fifth improvement region in graphical
form for an inductor component or family of components according to
the present invention including improved conductivity composite
material. Specifically, FIG. 35 indicates the required effective
permeability regions. A range of (.delta.) values are plotted along
the x-axis with a range of permeability values plotted along the
y-axis. For the reasons explained earlier, the required
permeability values in FIG. 35 do not correspond to the regions
407, 427 as shown and described in relation to FIG. 19. As such,
for any given value of (.delta.) the upper and lower limits of the
bounded region shown in FIG. 35 is different than the regions 407
and 427 that apply to cases wherein the core size is proportionally
varied in all dimensions without otherwise changing the shape.
[0173] 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
FIGS. 31-35 utilizes the methodology of FIG. 23 with similar
benefits. Once the parameters are selected or accepted as required,
the components can be fabricated by linearly reducing the core size
in the height dimension, but otherwise retaining its size and shape
in the length and width dimensions. Because the core area of the
inductor of the invention is the same as the reference inductor in
the length and width dimension, the mean turns per length in the
inventive inductor constructed is the same as the reference
conductor. Improvements such as those described above may otherwise
be realized using, for example, the graphs of FIGS. 31-35 instead
of the preceding graphs. Electromagnetic inductor components formed
according to the present invention may therefore be readily
obtained in view of the teachings of the present disclosure,
without necessarily undertaking the laborious task of theoretical
component design, and without necessarily incurring expensive and
time consuming experimentation of new component constructions.
Improved inductors having better performance may be provided at
relatively low cost while continuing to reduce the physical package
size of inductors and/or improving component performance in
different aspects or a combination of aspects. In view of the
inventive design approach described above, a vast number of
copper-based inductor components can be readily translated to new
and improved inductor devices using ultra-conductive composite
materials. Inductor designs can rather easily be optimized with
respect to one or more of a plurality of parameters. The benefits
of such components according to the invention are perhaps most
significant for miniaturized power inductor components used in
circuit boards of increasingly smaller and powerful electronic
devices, but the benefits also accrue to other types of inductors
as well.
[0174] The benefits and advantages of the inventive concepts are
now believed to have been amply illustrated in relation to the
exemplary embodiments disclosed.
[0175] 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 (.beta.) 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.
[0176] Optionally, the ratio of electrical conductivity (.beta.)
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.
[0177] 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.
[0178] Optionally, the ratio of electrical conductivity (.beta.)
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
(.beta.) and an effective diameter ratio (.delta.) 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.
[0179] Optionally, the saturation current value matches a
saturation current value for the reference inductor component. The
effective diameter ratio (.delta.) may be within a range of about 1
to about .beta..sup.(-1/2).
[0180] As further options, the effective diameter ratio (.delta.)
may be within a range of about 1 to about .beta..sup.-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 (.delta..sup.-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
[.beta..sup.(-1)*.delta..sup.(-4)] and a lower boundary value
defined by a function [.beta..sup.(-1)*.delta..sup.(-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 (.delta..sup.2).
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 (.delta..sup.2/3) and a lower
boundary value defined by a function (.delta..sup.2). 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 (.delta..sup.-2) and a lower boundary value defined by a
function (.delta..sup.(-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 .delta..sup.2. 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 (.delta..sup.-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 (.delta..sup.2/3) and a lower
boundary value defined by a function (.delta..sup.(2)).
[0181] 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 (.delta..sup.(-2)).
[0182] As still further options, an effective diameter ratio
(.delta.) of the conductor relative to the reference conductor
material may be within a range of about .beta..sup.-1/4 to about
.beta..sup.-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
[.beta.*.delta..sup.2] 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 [.beta..sup.(-1)*.delta..sup.(-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 [.beta.*.delta..sup.(4)] and a
lower boundary value defined by a function (.delta..sup.2).
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
(.beta.*.delta..sup.2) 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 .delta..sup.2/3 and a lower boundary value defined by a
function [.beta..sup.(-2/3)*.delta..sup.(-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 (.beta..sup.-1*.delta..sup.-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
[.beta..sup.(2/3)*.delta..sup.(2/3)] and a lower boundary defined
by a function (.delta..sup.(-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 [.beta.*.delta..sup.2] and a lower boundary value of
1.
[0183] 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 (.beta.) and the effective diameter ratio (.delta.) of
the conductor relative to the reference conductor material.
[0184] 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
(.beta.) of the composite conductor relative to the electrical
conductivity of the reference conductor material; based on the
determined ratio of electrical conductivity (.beta.), 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.
[0185] 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 (.delta.) 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 (.beta.) and the effective diameter ratio
(.delta.). 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 (.beta.) and the effective
diameter ratio (.delta.).
[0186] 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.
[0187] 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 (.beta.) and
the effective diameter ratio (.delta.). 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.
[0188] 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.
* * * * *