U.S. patent application number 12/572411 was filed with the patent office on 2012-06-21 for wireless power transfer for furnishings and building elements.
This patent application is currently assigned to QUALCOMM Incorporated. Invention is credited to Rinat Burdo, Virginia Walker Keating, Miles Alexander Lyell Kirby, Michael Mangan, Ernest Ozaki, William Von Novak.
Application Number | 20120153731 12/572411 |
Document ID | / |
Family ID | 41315494 |
Filed Date | 2012-06-21 |
United States Patent
Application |
20120153731 |
Kind Code |
A9 |
Kirby; Miles Alexander Lyell ;
et al. |
June 21, 2012 |
WIRELESS POWER TRANSFER FOR FURNISHINGS AND BUILDING ELEMENTS
Abstract
Exemplary embodiments are directed to wireless power transfer. A
power transmitting device is attached to an existing furniture item
or is embedded in a host furnishing. The power transmitting device
includes a transmit antenna to wirelessly transfer power to a
receive antenna by generating a near field radiation within a
coupling-mode region. An amplifier applies a driving signal to the
transmit antenna. A presence detector detects a presence of a
receiver device within the coupling-mode region. The presence
detector may also detect a human presence. An enclosed furnishing
detector detects when the furnishing item is in a closed state. A
power output may be adjusted in response to the closed state, the
presence of a receiver device, and the presence of a human.
Inventors: |
Kirby; Miles Alexander Lyell;
(San Diego, CA) ; Burdo; Rinat; (San Diego,
CA) ; Keating; Virginia Walker; (San Diego, CA)
; Ozaki; Ernest; (Poway, CA) ; Mangan;
Michael; (San Diego, CA) ; Von Novak; William;
(San Diego, CA) |
Assignee: |
QUALCOMM Incorporated
San Diego
CA
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20100201202 A1 |
August 12, 2010 |
|
|
Family ID: |
41315494 |
Appl. No.: |
12/572411 |
Filed: |
October 2, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12267041 |
Nov 7, 2008 |
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12572411 |
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61060735 |
Jun 11, 2008 |
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61060738 |
Jun 11, 2008 |
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61053008 |
May 13, 2008 |
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61053010 |
May 13, 2008 |
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61060741 |
Jun 11, 2008 |
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61053000 |
May 13, 2008 |
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61053004 |
May 13, 2008 |
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61081332 |
Jul 16, 2008 |
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61053012 |
May 13, 2008 |
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61053015 |
May 13, 2008 |
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Current U.S.
Class: |
307/104 |
Current CPC
Class: |
G06K 19/0715 20130101;
H01F 38/14 20130101; G06K 19/0723 20130101; H04B 5/02 20130101;
H01Q 1/38 20130101; H01Q 1/2225 20130101; H01Q 7/00 20130101; H04B
5/0037 20130101; H02J 7/025 20130101; H04B 5/0031 20130101; G06K
19/0701 20130101; G06K 7/10178 20130101; H02J 50/12 20160201; H02J
50/90 20160201; H02J 7/00034 20200101; H02J 50/005 20200101; G06K
7/0008 20130101 |
Class at
Publication: |
307/104 |
International
Class: |
H02J 17/00 20060101
H02J017/00 |
Claims
1. An apparatus, comprising: a power transmitting device for use on
a host furnishing comprising: a transmit antenna to wirelessly
transfer power to a receive antenna by generating a near field
radiation at a resonant frequency within a coupling-mode region;
and an amplifier for applying a driving signal to the transmit
antenna at the resonant frequency.
2. The apparatus of claim 1, further comprising the host furnishing
having associated therewith at least a planar portion of the
transmit antenna.
3. The apparatus of claim 2, further comprising one or more
additional power transmitting devices integrated as part of the
host furnishing, each of the one or more additional power
transmitting devices, comprising a transmit antenna operably
coupled to the amplifier for wirelessly transferring power to the
receive antenna by generating a near field radiation at a resonant
frequency within its coupling-mode region.
4. The apparatus of claim 3, comprising: a controller to control
activation of resonance of each of the power transmitting device
and the one or more additional power transmitting devices; and a
multiplexer coupled to the controller and for multiplexing a common
driving signal from the amplifier to the driving signal of each of
the power transmitting device and the one or more additional power
transmitting devices.
5. The apparatus of claim 4, wherein the controller controls
activation of each of the power transmitting device and the one or
more additional power transmitting devices by controlling the
multiplexer according to a time-domain sequencing of activation of
the power transmitting device and the one or more additional power
transmitting devices.
6. The apparatus of claim 3, wherein the one or more additional
power transmitting devices are positioned in a plane substantially
orthogonal to the power transmitting device.
7. The apparatus of claim 1, wherein the transmit antenna comprises
a continuous loop transmit antenna including a plurality of facets
oriented in a plurality of directions.
8. The apparatus of claim 7, wherein the plurality of directions
are substantially orthogonal.
9. The apparatus of claim 1, wherein the power transmitting device
further comprises: a presence detector for detecting a presence of
a receiver device bearing the receive antenna within the
coupling-mode region and generating a presence signal; and a
controller operably coupled to the presence detector and the
amplifier, the controller for adjusting a power output of the
amplifier responsive to the presence signal.
10. The apparatus of claim 2, wherein the host furnishing comprises
an enclosure for accepting one or more receiver devices bearing the
receive antenna.
11. The apparatus of claim 10, wherein the power transmitting
device further comprises: an enclosed furnishing detector for
detecting an enclosed state for the host furnishing; and a
controller operably coupled to the enclosed furnishing detector and
the amplifier, the controller for adjusting a power output of the
amplifier responsive to the enclosed state for the host
furnishing.
12. The apparatus of claim 10, wherein the enclosure comprises a
closet including at least one wall bearing the transmit
antenna.
13. The apparatus of claim 12, wherein the closet includes at least
one door bearing the transmit antenna.
14. The apparatus of claim 2, wherein the host furnishing is
selected from the group consisting of a cabinet, a cubby, a locker,
a table, a desk, a drawer, a bureau, and a shelf.
15. The apparatus of claim 2, wherein the at least a planar portion
of the transmit antenna is one of disposed thereon the host
furnishing or integrated therein with the host furnishing.
16. A method, comprising: disposing a power transmitting device
bearing a transmit antenna on an existing furniture item:
generating an electromagnetic field at a resonant frequency of the
transmit antenna to create a coupling-mode region within a near
field of the transmit antenna; and disposing a receive device
bearing a receive antenna in the coupling-mode region.
17. The method of claim 16, further comprising: detecting a human
presence within a regulatory distance of the electromagnetic field;
adjusting a power output of the transmit antenna responsive to the
human presence to a regulatory level or lower; and adjusting the
power output of the transmit antenna responsive to a human absence
to a level above the regulatory level.
18. The method of claim 16, further comprising: detecting a
presence of a receiver device within the coupling-mode region; and
stopping the generating the electromagnetic field when the
detecting the presence indicates the absence of any receiver
devices in the coupling-mode region.
19. The method of claim 16, further comprising: detecting an
enclosed state for the existing furniture item; and adjusting a
power output of the transmit antenna responsive to the enclosed
state for the existing furniture item.
20. A wireless power transfer system, comprising: means for
disposing a power transmitting device in a host furnishing; means
for generating an electromagnetic field at a resonant frequency of
a transmit antenna in the power transmitting device to create a
coupling-mode region within a near field of the transmit antenna;
means for detecting a presence of a receive antenna in the
coupling-mode region; means for adjusting a power output of the
transmit antenna responsive to the presence of the receive antenna;
and means for receiving power from the coupling-mode region with
the receive antenna disposed within the coupling-mode region.
21. The system of claim 20, further comprising: means for detecting
a human presence within a regulatory distance of the
electromagnetic field; means for adjusting the power output of the
transmit antenna responsive to the human presence to a regulatory
level or lower; and means for adjusting the power output of the
transmit antenna responsive to a human absence to a level above the
regulatory level.
22. The system of claim 20, further comprising: means for detecting
an enclosed state for the host furnishing; and adjusting the power
output of the transmit antenna responsive to the enclosed state for
the host furnishing.
23. A wireless power transfer system, comprising: means for
attaching a power transmitting device to an existing furniture
item; means for generating an electromagnetic field at a resonant
frequency of a transmit antenna in the power transmitting device to
create a coupling-mode region within a near field of the transmit
antenna; means for detecting a presence of a receive antenna in the
coupling-mode region; means for adjusting a power output of the
transmit antenna responsive to the presence of the receive antenna;
and means for receiving power from the coupling-mode region with
the receive antenna disposed within the coupling-mode region.
24. The system of claim 23, further comprising: means for detecting
a human presence within a regulatory distance of the
electromagnetic field; means for adjusting the power output of the
transmit antenna responsive to the human presence to a regulatory
level or lower; and means for adjusting the power output of the
transmit antenna responsive to a human absence to a level above the
regulatory level.
25. The system of claim 23, further comprising: means for detecting
an enclosed state for the existing furniture item; and means for
adjusting the power output of the transmit antenna responsive to
the enclosed state for the existing furniture item.
Description
[0001] This application claims priority under 35 U.S.C.
.sctn.119(e) to:
[0002] U.S. Provisional Patent Application 61/152,088 entitled
"WIRELESS POWER CHARGERS IN FURNITURE" filed on Feb. 12, 2009, and
assigned to the assignee hereof and hereby expressly incorporated
by reference herein;
[0003] U.S. Provisional Patent Application 61/164,411 entitled
"WIRELESS POWER CHARGERS IN FURNITURE" filed on Mar. 28, 2009, and
assigned to the assignee hereof and hereby expressly incorporated
by reference herein;
[0004] U.S. Provisional Patent Application 61/163,376 entitled
"WALL-MOUNTED WIRELESS CHARGING" filed on Mar. 25, 2009, and
assigned to the assignee hereof and hereby expressly incorporated
by reference herein; and
[0005] U.S. Provisional Patent Application 61/151,290, entitled
"MULTI DIMENSIONAL WIRELESS CHARGER" filed on Feb. 10, 2009, and
assigned to the assignee hereof and hereby expressly incorporated
by reference herein.
BACKGROUND
[0006] Typically, each battery powered device such as a wireless
electronic device requires its own charger and power source, which
is usually an alternating current (AC) power outlet. Such a wired
configuration becomes unwieldy when many devices need charging.
[0007] Approaches are being developed that use over-the-air or
wireless power transmission between a transmitter and a receiver
coupled to the electronic device to be charged. Such approaches
generally fall into two categories. One is based on the coupling of
plane wave radiation (also called far-field radiation) between a
transmit antenna and a receive antenna on the device to be charged.
The receive antenna collects the radiated power and rectifies it
for charging the battery. Antennas are generally of resonant length
in order to improve the coupling efficiency. This approach suffers
from the fact that the power coupling falls off quickly with
distance between the antennas, so charging over reasonable
distances (e.g., less than 1 to 2 meters) becomes difficult.
Additionally, since the transmitting system radiates plane waves,
unintentional radiation can interfere with other systems if not
properly controlled through filtering.
[0008] Other approaches to wireless energy transmission techniques
are based on inductive coupling between a transmit antenna
embedded, for example, in a "charging" mat or surface and a receive
antenna (plus a rectifying circuit) embedded in the host electronic
device to be charged. This approach has the disadvantage that the
spacing between transmit and receive antennas must be very close
(e.g., within thousandths of meters). Though this approach does
have the capability to simultaneously charge multiple devices in
the same area, this area is typically very small and requires the
user to accurately locate the devices to a specific area.
Therefore, there is a need to provide a wireless charging
arrangement that accommodates flexible placement and orientation of
transmit and receive antennas.
[0009] With wireless power transmission there is a need for systems
and methods for disposing the transmit antennas in furniture or
buildings to convenient and unobtrusive wireless power
transmission. There is also a need for adjusting the operating
characteristics of the antennas to adapt to different circumstances
and optimize power transfer characteristics.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 shows a simplified block diagram of a wireless power
transfer system.
[0011] FIG. 2 shows a simplified schematic diagram of a wireless
power transfer system.
[0012] FIG. 3 shows a schematic diagram of a loop antenna for use
in exemplary embodiments of the present invention.
[0013] FIG. 4 shows simulation results indicating coupling strength
between transmit and receive antennas.
[0014] FIGS. 5A and 5B show layouts of loop antennas for transmit
and receive antennas according to exemplary embodiments of the
present invention.
[0015] FIG. 6 shows simulation results indicating coupling strength
between transmit and receive antennas relative to various
circumference sizes for the square and circular transmit antennas
illustrated in FIGS. 5A and 5B.
[0016] FIG. 7 shows simulation results indicating coupling strength
between transmit and receive antennas relative to various surface
areas for the square and circular transmit antennas illustrated in
FIGS. 5A and 5B.
[0017] FIG. 8 shows various placement points for a receive antenna
relative to a transmit antenna to illustrate coupling strengths in
coplanar and coaxial placements.
[0018] FIG. 9 shows simulation results indicating coupling strength
for coaxial placement at various distances between the transmit and
receive antennas.
[0019] FIG. 10 is a simplified block diagram of a transmitter, in
accordance with an exemplary embodiment of the present
invention.
[0020] FIG. 11 is a simplified block diagram of a receiver, in
accordance with an exemplary embodiment of the present
invention.
[0021] FIG. 12 shows a simplified schematic of a portion of
transmit circuitry for carrying out messaging between a transmitter
and a receiver.
[0022] FIGS. 13A-13C shows a simplified schematic of a portion of
receive circuitry in various states to illustrate messaging between
a receiver and a transmitter.
[0023] FIGS. 14A-14C shows a simplified schematic of a portion of
alternative receive circuitry in various states to illustrate
messaging between a receiver and a transmitter.
[0024] FIGS. 15A-15D are simplified block diagrams illustrating a
beacon power mode for transmitting power between a transmitter and
a receiver.
[0025] FIG. 16A illustrates a large transmit antenna with a smaller
repeater antenna disposed coplanar with, and coaxial with, the
transmit antenna.
[0026] FIG. 16B illustrates a transmit antenna with a larger
repeater antenna with a coaxial placement relative to the transmit
antenna.
[0027] FIG. 17A illustrates a large transmit antenna with a three
different smaller repeater antennas disposed coplanar with, and
within a perimeter of, the transmit antenna.
[0028] FIG. 17B illustrates a large transmit antenna with smaller
repeater antennas with offset coaxial placements and offset
coplanar placements relative to the transmit antenna.
[0029] FIG. 18 shows simulation results indicating coupling
strength between a transmit antenna, a repeater antenna and a
receive antenna.
[0030] FIG. 19A shows simulation results indicating coupling
strength between a transmit antenna and receive antenna with no
repeater antennas.
[0031] FIG. 19B shows simulation results indicating coupling
strength between a transmit antenna and receive antenna with a
repeater antenna.
[0032] FIG. 20 is a simplified block diagram of a transmitter
according to one or more exemplary embodiments of the present
invention.
[0033] FIG. 21 is a simplified block diagram of a multiple transmit
antenna wireless charging apparatus, in accordance with an
exemplary embodiment of the present invention.
[0034] FIG. 22 is a simplified block diagram of a multiple transmit
antenna wireless charging apparatus, in accordance with another
exemplary embodiment of the present invention.
[0035] FIGS. 23A-23C illustrate an exemplary embodiment of an item
bearing transmit antennas oriented in multiple directions.
[0036] FIGS. 24A and 24B illustrate an exemplary embodiment of a
cabinet bearing transmit antennas oriented in multiple
directions.
[0037] FIG. 25 illustrates an exemplary embodiment of a transmitter
disposed in or on a table.
[0038] FIG. 26 illustrates an exemplary embodiment of a transmitter
in or on a shelf.
[0039] FIG. 27 illustrates an exemplary embodiment of a transmitter
disposed in or on a bureau.
[0040] FIG. 28 illustrates an exemplary embodiment of a transmitter
disposed in or on a drawer.
[0041] FIGS. 29A-29C illustrates an exemplary embodiment of an
enclosure bearing one or more transmitters in various
configurations.
[0042] FIG. 30 illustrates an exemplary embodiment of a transmitter
disposed in or on a closet.
[0043] FIG. 31 illustrates an exemplary embodiment of a transmitter
disposed in or on a bed,
[0044] FIG. 32 illustrates an exemplary embodiment of a transmitter
disposed in or on a rug,
[0045] FIG. 33 illustrates an exemplary embodiment of a
wall-mounted receptacle bearing a transmitter and for holding one
or more receiver devices.
[0046] FIG. 34 illustrates an exemplary embodiment of a transmitter
disposed on a wall and one or receiver device holders for holding
one or more receiver devices in a coupling-mode region of the
transmitter.
[0047] FIG. 35 is a simplified flow chart illustrating acts that
may be performed in one or more exemplary embodiments of the
present invention.
DETAILED DESCRIPTION
[0048] The word "exemplary" is used herein to mean "serving as an
example, instance, or illustration." Any embodiment described
herein as "exemplary" is not necessarily to be construed as
preferred or advantageous over other embodiments.
[0049] The detailed description set forth below in connection with
the appended drawings is intended as a description of exemplary
embodiments of the present invention and is not intended to
represent the only embodiments in which the present invention can
be practiced. The term "exemplary" used throughout this description
means "serving as an example, instance, or illustration," and
should not necessarily be construed as preferred or advantageous
over other exemplary embodiments. The detailed description includes
specific details for the purpose of providing a thorough
understanding of the exemplary embodiments of the invention. It
will be apparent to those skilled in the art that the exemplary
embodiments of the invention may be practiced without these
specific details. In some instances, well-known structures and
devices are shown in block diagram form in order to avoid obscuring
the novelty of the exemplary embodiments presented herein.
[0050] The words "wireless power" is used herein to mean any form
of energy associated with electric fields, magnetic fields,
electromagnetic fields, or otherwise that is transmitted between
from a transmitter to a receiver without the use of physical
electromagnetic conductors.
[0051] FIG. 1 illustrates wireless transmission or charging system
100, in accordance with various exemplary embodiments of the
present invention. Input power 102 is provided to a transmitter 104
for generating a radiated field 106 for providing energy transfer.
A receiver 108 couples to the radiated field 106 and generates an
output power 110 for storing or consumption by a device (not shown)
coupled to the output power 110. Both the transmitter 104 and the
receiver 108 are separated by a distance 112. In one exemplary
embodiment, transmitter 104 and receiver 108 are configured
according to a mutual resonant relationship and when the resonant
frequency of receiver 108 and the resonant frequency of transmitter
104 are exactly identical, transmission losses between the
transmitter 104 and the receiver 108 are minimal when the receiver
108 is located in the "near-field" of the radiated field 106.
[0052] Transmitter 104 further includes a transmit antenna 114 for
providing a means for energy transmission and receiver 108 further
includes a receive antenna 118 for providing a means for energy
reception. The transmit and receive antennas are sized according to
applications and devices to be associated therewith. As stated, an
efficient energy transfer occurs by coupling a large portion of the
energy in the near-field of the transmitting antenna to a receiving
antenna rather than propagating most of the energy in an
electromagnetic wave to the far field. When in this near-field a
coupling mode may be developed between the transmit antenna 114 and
the receive antenna 118. The area around the antennas 114 and 118
where this near-field coupling may occur is referred to herein as a
coupling-mode region.
[0053] FIG. 2 shows a simplified schematic diagram of a wireless
power transfer system. The transmitter 104 includes an oscillator
122, a power amplifier 124 and a filter and matching circuit 126.
The oscillator is configured to generate at a desired frequency,
which may be adjusted in response to adjustment signal 123. The
oscillator signal may be amplified by the power amplifier 124 with
an amplification amount responsive to control signal 125. The
filter and matching circuit 126 may be included to filter out
harmonics or other unwanted frequencies and match the impedance of
the transmitter 104 to the transmit antenna 114.
[0054] The receiver may include a matching circuit 132 and a
rectifier and switching circuit to generate a DC power output to
charge a battery 136 as shown in FIG. 2 or power a device coupled
to the receiver (not shown). The matching circuit 132 may be
included to match the impedance of the receiver 108 to the receive
antenna 118.
[0055] As illustrated in FIG. 3, antennas used in exemplary
embodiments may be configured as a "loop" antenna 150, which may
also be referred to herein as a "magnetic" antenna. Loop antennas
may be configured to include an air core or a physical core such as
a ferrite core. Air core loop antennas may be more tolerable to
extraneous physical devices placed in the vicinity of the core.
Furthermore, an air core loop antenna allows the placement of other
components within the core area. In addition, an air core loop may
more readily enable placement of the receive antenna 118 (FIG. 2)
within a plane of the transmit antenna 114 (FIG. 2) where the
coupled-mode region of the transmit antenna 114 (FIG. 2) may be
more powerful.
[0056] As stated, efficient transfer of energy between the
transmitter 104 and receiver 108 occurs during matched or nearly
matched resonance between the transmitter 104 and the receiver 108.
However, even when resonance between the transmitter 104 and
receiver 108 are not matched, energy may be transferred at a lower
efficiency. Transfer of energy occurs by coupling energy from the
near-field of the transmitting antenna to the receiving antenna
residing in the neighborhood where this near-field is established
rather than propagating the energy from the transmitting antenna
into free space.
[0057] The resonant frequency of the loop or magnetic antennas is
based on the inductance and capacitance. Inductance in a loop
antenna is generally simply the inductance created by the loop,
whereas, capacitance is generally added to the loop antenna's
inductance to create a resonant structure at a desired resonant
frequency. As a non-limiting example, capacitor 152 and capacitor
154 may be added to the antenna to create a resonant circuit that
generates resonant signal 156. Accordingly, for larger diameter
loop antennas, the size of capacitance needed to induce resonance
decreases as the diameter or inductance of the loop increases.
Furthermore, as the diameter of the loop or magnetic antenna
increases, the efficient energy transfer area of the near-field
increases. Of course, other resonant circuits are possible. As
another non-limiting example, a capacitor may be placed in parallel
between the two terminals of the loop antenna. In addition, those
of ordinary skill in the art will recognize that for transmit
antennas the resonant signal 156 may be an input to the loop
antenna 150.
[0058] Exemplary embodiments of the invention include coupling
power between two antennas that are in the near-fields of each
other. As stated, the near-field is an area around the antenna in
which electromagnetic fields exist but may not propagate or radiate
away from the antenna. They are typically confined to a volume that
is near the physical volume of the antenna. In the exemplary
embodiments of the invention, magnetic type antennas such as single
and multi-turn loop antennas are used for both transmit (Tx) and
receive (Rx) antenna systems since magnetic near-field amplitudes
tend to be higher for magnetic type antennas in comparison to the
electric near-fields of an electric-type antenna (e.g., a small
dipole). This allows for potentially higher coupling between the
pair. Furthermore, "electric" antennas (e.g., dipoles and
monopoles) or a combination of magnetic and electric antennas is
also contemplated.
[0059] The Tx antenna can be operated at a frequency that is low
enough and with an antenna size that is large enough to achieve
good coupling (e.g., >-4 dB) to a small Rx antenna at
significantly larger distances than allowed by far field and
inductive approaches mentioned earlier. If the Tx antenna is sized
correctly, high coupling levels (e.g., -2 to -4 dB) can be achieved
when the Rx antenna on a host device is placed within a
coupling-mode region (i.e., in the near-field) of the driven Tx
loop antenna.
[0060] FIG. 4 shows simulation results indicating coupling strength
between transmit and receive antennas. Curves 170 and 172 indicate
a measure of acceptance of power by the transmit and receive
antennas, respectively. In other words, with a large negative
number there is a very close impedance match and most of the power
is accepted and, as a result, radiated by the transmit antenna.
Conversely, a small negative number indicates that much of the
power is reflected back from the antenna because there is not a
close impedance match at the given frequency. In FIG. 4, the
transmit antenna and the receive antenna are tuned to have a
resonant frequency of about 13.56 MHz.
[0061] Curve 170 illustrates the amount of power transmitted from
the transmit antenna at various frequencies. Thus, at points 1a and
3a, corresponding to about 13.528 MHz and 13.593 MHz, much of the
power is reflected and not transmitted out of the transmit antenna.
However, at point 2a, corresponding to about 13.56 MHz, it can be
seen that a large amount of the power is accepted and transmitted
out of the antenna.
[0062] Similarly, curve 172 illustrates the amount of power
received by the receive antenna at various frequencies. Thus, at
points 1b and 3b, corresponding to about 13.528 MHz and 13.593 MHz,
much of the power is reflected and not conveyed through the receive
antenna and into the receiver. However, at point 2b corresponding
to about 13.56 MHz, it can be seen that a large amount of the power
is accepted by the receive antenna and conveyed into the
receiver.
[0063] Curve 174 indicates the amount of power received at the
receiver after being sent from the transmitter through the transmit
antenna, received through the receive antenna and conveyed to the
receiver. Thus, at points 1c and 3c, corresponding to about 13.528
MHz and 13.593 MHz, much of the power sent out of the transmitter
is not available at the receiver because (1) the transmit antenna
rejects much of the power sent to it from the transmitter and (2)
the coupling between the transmit antenna and the receive antenna
is less efficient as the frequencies move away from the resonant
frequency. However, at point 2c corresponding to about 13.56 MHz,
it can be seen that a large amount of the power sent from the
transmitter is available at the receiver, indicating a high degree
of coupling between the transmit antenna and the receive
antenna.
[0064] FIGS. 5A and 5B show layouts of loop antennas for transmit
and receive antennas according to exemplary embodiments of the
present invention. Loop antennas may be configured in a number of
different ways, with single loops or multiple loops at wide variety
of sizes. In addition, the loops may be a number of different
shapes, such as, for example only, circular, elliptical, square,
and rectangular. FIG. 5A illustrates a large square loop transmit
antenna 114S and a small square loop receive antenna 118 placed in
the same plane as the transmit antenna 114S and near the center of
the transmit antenna 114S. FIG. 5B illustrates a large circular
loop transmit antenna 114C and a small square loop receive antenna
118' placed in the same plane as the transmit antenna 114C and near
the center of the transmit antenna 114C. The square loop transmit
antenna 114S has side lengths of "a" while the circular loop
transmit antenna 114C has a diameter of ".PHI.." For a square loop,
it can be shown that there is an equivalent circular loop whose
diameter may be defined as: .PHI..sub.eq=4a/.pi..
[0065] FIG. 6 shows simulation results indicating coupling strength
between transmit and receive antennas relative to various
circumferences for the square and circular transmit antennas
illustrated in FIGS. 4A and 4B. Thus, curve 180 shows coupling
strength between the circular loop transmit antennas 114C and the
receive antenna 118 at various circumference sizes for the circular
loop transmit antenna 114C. Similarly, curve 182 shows coupling
strength between the square loop transmit antennas 114S and the
receive antenna 118' at various equivalent circumference sizes for
the transmit loop transmit antenna 114S.
[0066] FIG. 7 shows simulation results indicating coupling strength
between transmit and receive antennas relative to various surface
areas for the square and circular transmit antennas illustrated in
FIGS. 5A and 5B. Thus, curve 190 shows coupling strength between
the circular loop transmit antennas 114C and the receive antenna
118 at various surface areas for the circular loop transmit antenna
114C. Similarly, curve 192 shows coupling strength between the
square loop transmit antennas 114S and the receive antenna 118' at
various surface areas for the transmit loop transmit antenna
114S.
[0067] FIG. 8 shows various placement points for a receive antenna
relative to a transmit antenna to illustrate coupling strengths in
coplanar and coaxial placements. "Coplanar," as used herein, means
that the transmit antenna and receive antenna have planes that are
substantially aligned (i.e., have surface normals pointing in
substantially the same direction) and with no distance (or a small
distance) between the planes of the transmit antenna and the
receive antenna. "Coaxial," as used herein, means that the transmit
antenna and receive antenna have planes that are substantially
aligned (i.e., have surface normals pointing in substantially the
same direction) and the distance between the two planes is not
trivial and furthermore, the surface normal of the transmit antenna
and the receive antenna lie substantially along the same vector, or
the two normals are in echelon.
[0068] As examples, points p1, p2, p3, and p7 are all coplanar
placement points for a receive antenna relative to a transmit
antenna. As another example, point p5 and p6 are coaxial placement
points for a receive antenna relative to a transmit antenna. The
table below shows coupling strength (S21) and coupling efficiency
(expressed as a percentage of power transmitted from the transmit
antenna that reached the receive antenna) at the various placement
points (p1-p7) illustrated in FIG. 8.
TABLE-US-00001 TABLE 1 Efficiency (TX Distance from S21 efficiency
DC power in to Position plane (cm) (%) RX DC power out) p1 0 46.8
28 p2 0 55.0 36 p3 0 57.5 35 p4 2.5 49.0 30 p5 17.5 24.5 15 p6 17.5
0.3 0.2 p7 0 5.9 3.4
[0069] As can be seen, the coplanar placement points p1, p2, and
p3, all show relatively high coupling efficiencies. Placement point
p7 is also a coplanar placement point, but is outside of the
transmit loop antenna. While placement point p7 does not have a
high coupling efficiency, it is clear that there is some coupling
and the coupling-mode region extends beyond the perimeter of the
transmit loop antenna.
[0070] Placement point p5 is coaxial with the transmit antenna and
shows substantial coupling efficiency. The coupling efficiency for
placement point p5 is not as high as the coupling efficiencies for
the coplanar placement points. However, the coupling efficiency for
placement point p5 is high enough that substantial power can be
conveyed between the transmit antenna and a receive antenna in a
coaxial placement.
[0071] Placement point p4 is within the circumference of the
transmit antenna but at a slight distance above the plane of the
transmit antenna in a position that may be referred to as an offset
coaxial placement (i.e., with surface normals in substantially the
same direction but at different locations) or offset coplanar
(i.e., with surface normals in substantially the same direction but
with planes that are offset relative to each other). From the table
it can be seen that with an offset distance of 2.5 cm, placement
point p4 still has relatively good coupling efficiency.
[0072] Placement point p6 illustrates a placement point outside the
circumference of the transmit antenna and at a substantial distance
above the plane of the transmit antenna. As can be seen from the
table, placement point p7 shows little coupling efficiency between
the transmit and receive antennas.
[0073] FIG. 9 shows simulation results indicating coupling strength
for coaxial placement at various distances between the transmit and
receive antennas. The simulations for FIG. 9 are for square
transmit and receive antennas in a coaxial placement, both with
sides of about 1.2 meters and at a transmit frequency of 10 MHz. It
can be seen that the coupling strength remains quite high and
uniform at distances of less than about 0.5 meters.
[0074] FIG. 10 is a simplified block diagram of a transmitter, in
accordance with an exemplary embodiment of the present invention. A
transmitter 200 includes transmit circuitry 202 and a transmit
antenna 204. Generally, transmit circuitry 202 provides RF power to
the transmit antenna 204 by providing an oscillating signal
resulting in generation of near-field energy about the transmit
antenna 204. By way of example, transmitter 200 may operate at the
13.56 MHz ISM band.
[0075] Exemplary transmit circuitry 202 includes a fixed impedance
matching circuit 206 for matching the impedance of the transmit
circuitry 202 (e.g., 50 ohms) to the transmit antenna 204 and a low
pass filter (LPF) 208 configured to reduce harmonic emissions to
levels to prevent self-jamming of devices coupled to receivers 108
(FIG. 1). Other embodiments may include different filter
topologies, including but not limited to, notch filters that
attenuate specific frequencies while passing others and may include
an adaptive impedance match, that can be varied based on measurable
transmit metrics, such as output power to the antenna or DC current
draw by the power amplifier. Transmit circuitry 202 further
includes a power amplifier 210 configured to drive an RF signal as
determined by an oscillator 212. The transmit circuitry may be
comprised of discrete devices or circuits, or alternately, may be
comprised of an integrated assembly. An exemplary RF power output
from transmit antenna 204 may be on the order of 2.5 Watts.
[0076] Transmit circuitry 202 further includes a processor 214 for
enabling the oscillator 212 during transmit phases (or duty cycles)
for specific receivers, for adjusting the frequency of the
oscillator, and for adjusting the output power level for
implementing a communication protocol for interacting with
neighboring devices through their attached receivers.
[0077] The transmit circuitry 202 may further include a load
sensing circuit 216 for detecting the presence or absence of active
receivers in the vicinity of the near-field generated by transmit
antenna 204. By way of example, a load sensing circuit 216 monitors
the current flowing to the power amplifier 210, which is affected
by the presence or absence of active receivers in the vicinity of
the near-field generated by transmit antenna 204. Detection of
changes to the loading on the power amplifier 210 are monitored by
processor 214 for use in determining whether to enable the
oscillator 212 for transmitting energy to communicate with an
active receiver.
[0078] Transmit antenna 204 may be implemented as an antenna strip
with the thickness, width and metal type selected to keep resistive
losses low. In a conventional implementation, the transmit antenna
204 can generally be configured for association with a larger
structure such as a table, mat, lamp or other less portable
configuration. Accordingly, the transmit antenna 204 generally will
not need "turns" in order to be of a practical dimension. An
exemplary implementation of a transmit antenna 204 may be
"electrically small" (i.e., fraction of the wavelength) and tuned
to resonate at lower usable frequencies by using capacitors to
define the resonant frequency. In an exemplary application where
the transmit antenna 204 may be larger in diameter, or length of
side if a square loop, (e.g., 0.50 meters) relative to the receive
antenna, the transmit antenna 204 will not necessarily need a large
number of turns to obtain a reasonable capacitance.
[0079] FIG. 11 is a block diagram of a receiver, in accordance with
an exemplary embodiment of the present invention. A receiver 300
includes receive circuitry 302 and a receive antenna 304. Receiver
300 further couples to device 350 for providing received power
thereto. It should be noted that receiver 300 is illustrated as
being external to device 350 but may be integrated into device 350.
Generally, energy is propagated wirelessly to receive antenna 304
and then coupled through receive circuitry 302 to device 350.
[0080] Receive antenna 304 is tuned to resonate at the same
frequency, or near the same frequency, as transmit antenna 204
(FIG. 10). Receive antenna 304 may be similarly dimensioned with
transmit antenna 204 or may be differently sized based upon the
dimensions of an associated device 350. By way of example, device
350 may be a portable electronic device having diametric or length
dimension smaller that the diameter of length of transmit antenna
204. In such an example, receive antenna 304 may be implemented as
a multi-turn antenna in order to reduce the capacitance value of a
tuning capacitor (not shown) and increase the receive antenna's
impedance. By way of example, receive antenna 304 may be placed
around the substantial circumference of device 350 in order to
maximize the antenna diameter and reduce the number of loop turns
(i.e., windings) of the receive antenna and the inter-winding
capacitance.
[0081] Receive circuitry 302 provides an impedance match to the
receive antenna 304. Receive circuitry 302 includes power
conversion circuitry 306 for converting a received RF energy source
into charging power for use by device 350. Power conversion
circuitry 306 includes an RF-to-DC converter 308 and may also in
include a DC-to-DC converter 310. RF-to-DC converter 308 rectifies
the RF energy signal received at receive antenna 304 into a
non-alternating power while DC-to-DC converter 310 converts the
rectified RF energy signal into an energy potential (e.g., voltage)
that is compatible with device 350. Various RF-to-DC converters are
contemplated including partial and full rectifiers, regulators,
bridges, doublers, as well as linear and switching converters.
[0082] Receive circuitry 302 may further include switching
circuitry 312 for connecting receive antenna 304 to the power
conversion circuitry 306 or alternatively for disconnecting the
power conversion circuitry 306. Disconnecting receive antenna 304
from power conversion circuitry 306 not only suspends charging of
device 350, but also changes the "load" as "seen" by the
transmitter 200 (FIG. 2) as is explained more fully below. As
disclosed above, transmitter 200 includes load sensing circuit 216
which detects fluctuations in the bias current provided to
transmitter power amplifier 210. Accordingly, transmitter 200 has a
mechanism for determining when receivers are present in the
transmitter's near-field.
[0083] When multiple receivers 300 are present in a transmitter's
near-field, it may be desirable to time-multiplex the loading and
unloading of one or more receivers to enable other receivers to
more efficiently couple to the transmitter. A receiver may also be
cloaked in order to eliminate coupling to other nearby receivers or
to reduce loading on nearby transmitters. This "unloading" of a
receiver is also known herein as a "cloaking". Furthermore, this
switching between unloading and loading controlled by receiver 300
and detected by transmitter 200 provides a communication mechanism
from receiver 300 to transmitter 200 as is explained more fully
below. Additionally, a protocol can be associated with the
switching which enables the sending of a message from receiver 300
to transmitter 200. By way of example, a switching speed may be on
the order of 100 .mu.sec.
[0084] In an exemplary embodiment, communication between the
transmitter and the receiver refers to a device sensing and
charging control mechanism, rather than conventional two-way
communication. In other words, the transmitter uses on/off keying
of the transmitted signal to adjust whether energy is available in
the near-filed. The receivers interpret these changes in energy as
a message from the transmitter. From the receiver side, the
receiver uses tuning and de-tuning of the receive antenna to adjust
how much power is being accepted from the near-field. The
transmitter can detect this difference in power used from the near
field and interpret these changes as a message from the
receiver.
[0085] Receive circuitry 302 may further include signaling detector
and beacon circuitry 314 used to identify received energy
fluctuations, which may correspond to informational signaling from
the transmitter to the receiver. Furthermore, signaling and beacon
circuitry 314 may also be used to detect the transmission of a
reduced RF signal energy (i.e., a beacon signal) and to rectify the
reduced RF signal energy into a nominal power for awakening either
un-powered or power-depleted circuits within receive circuitry 302
in order to configure receive circuitry 302 for wireless
charging.
[0086] Receive circuitry 302 further includes processor 316 for
coordinating the processes of receiver 300 described herein
including the control of switching circuitry 312 described herein.
Cloaking of receiver 300 may also occur upon the occurrence of
other events including detection of an external wired charging
source (e.g., wall/USB power) providing charging power to device
350. Processor 316, in addition to controlling the cloaking of the
receiver, may also monitor beacon circuitry 314 to determine a
beacon state and extract messages sent from the transmitter.
Processor 316 may also adjust DC-to-DC converter 310 for improved
performance.
[0087] FIG. 12 shows a simplified schematic of a portion of
transmit circuitry for carrying out messaging between a transmitter
and a receiver. In some exemplary embodiments of the present
invention, a means for communication may be enabled between the
transmitter and the receiver. In FIG. 12 a power amplifier 210
drives the transmit antenna 204 to generate the radiated field. The
power amplifier is driven by a carrier signal 220 that is
oscillating at a desired frequency for the transmit antenna 204. A
transmit modulation signal 224 is used to control the output of the
power amplifier 210.
[0088] The transmit circuitry can send signals to receivers by
using an ON/OFF keying process on the power amplifier 210. In other
words, when the transmit modulation signal 224 is asserted, the
power amplifier 210 will drive the frequency of the carrier signal
220 out on the transmit antenna 204. When the transmit modulation
signal 224 is negated, the power amplifier will not drive out any
frequency on the transmit antenna 204.
[0089] The transmit circuitry of FIG. 12 also includes a load
sensing circuit 216 that supplies power to the power amplifier 210
and generates a receive signal 235 output. In the load sensing
circuit 216 a voltage drop across resistor R.sub.s develops between
the power in signal 226 and the power supply 228 to the power
amplifier 210. Any change in the power consumed by the power
amplifier 210 will cause a change in the voltage drop that will be
amplified by differential amplifier 230. When the transmit antenna
is in coupled mode with a receive antenna in a receiver (not shown
in FIG. 12) the amount of current drawn by the power amplifier 210
will change. In other words, if no coupled mode resonance exist for
the transmit antenna 210, the power required to drive the radiated
field will be first amount. If a coupled mode resonance exists, the
amount of power consumed by the power amplifier 210 will go up
because much of the power is being coupled into the receive
antenna. Thus, the receive signal 235 can indicate the presence of
a receive antenna coupled to the transmit antenna 235 and can also
detect signals sent from the receive antenna, as explained below.
Additionally, a change in receiver current draw will be observable
in the transmitter's power amplifier current draw, and this change
can be used to detect signals from the receive antennas, as
explained below.
[0090] FIGS. 13A-13C shows a simplified schematic of a portion of
receive circuitry in various states to illustrate messaging between
a receiver and a transmitter. All of FIGS. 13A-13C show the same
circuit elements with the difference being state of the various
switches. A receive antenna 304 includes a characteristic
inductance L1, which drives node 350. Node 350 is selectively
coupled to ground through switch S1A. Node 350 is also selectively
coupled to diode D1 and rectifier 318 through switch SIB. The
rectifier 318 supplies a DC power signal 322 to a receive device
(not shown) to power the receive device, charge a battery, or a
combination thereof. The diode D1 is coupled to a transmit signal
320 which is filtered to remove harmonics and unwanted frequencies
with capacitor C3 and resistor R1. Thus the combination of D1, C3,
and R1 can generate a signal on the transmit signal 320 that mimics
the transmit modulation generated by the transmit modulation signal
224 discussed above with reference to the transmitter in FIG.
12.
[0091] Exemplary embodiments of the invention includes modulation
of the receive device's current draw and modulation of the receive
antenna's impedance to accomplish reverse link signaling. With
reference to both FIG. 13A and FIG. 12, as the power draw of the
receive device changes, the load sensing circuit 216 detects the
resulting power changes on the transmit antenna and from these
changes can generate the receive signal 235.
[0092] In the exemplary embodiments of FIGS. 13A-13C, the current
draw through the transmitter can be changed by modifying the state
of switches S1A and S2A. In FIG. 13A, switch S1A and switch S2A are
both open creating a "DC open state" and essentially removing the
load from the transmit antenna 204. This reduces the current seen
by the transmitter.
[0093] In FIG. 13B, switch S1A is closed and switch S2A is open
creating a "DC short state" for the receive antenna 304. Thus the
state in FIG. 13B can be used to increase the current seen in the
transmitter.
[0094] In FIG. 13C, switch S1A is open and switch S2A is closed
creating a normal receive mode (also referred to herein as a "DC
operating state") wherein power can be supplied by the DC out
signal 322 and a transmit signal 320 can be detected. In the state
shown in FIG. 13C the receiver receives a normal amount of power,
thus consuming more or less power from the transmit antenna than
the DC open state or the DC short state.
[0095] Reverse link signaling may be accomplished by switching
between the DC operating state (FIG. 13C) and the DC short state
(FIG. 13B). Reverse link signaling also may be accomplished by
switching between the DC operating state (FIG. 13C) and the DC open
state (FIG. 13A).
[0096] FIGS. 14A-14C shows a simplified schematic of a portion of
alternative receive circuitry in various states to illustrate
messaging between a receiver and a transmitter.
[0097] All of FIGS. 14A-14C show the same circuit elements with the
difference being state of the various switches. A receive antenna
304 includes a characteristic inductance L1, which drives node 350.
Node 350 is selectively coupled to ground through capacitor C1 and
switch SIB. Node 350 is also AC coupled to diode D1 and rectifier
318 through capacitor C2. The diode D1 is coupled to a transmit
signal 320 which is filtered to remove harmonics and unwanted
frequencies with capacitor C3 and resistor R1. Thus the combination
of D1, C3, and R1 can generate a signal on the transmit signal 320
that mimics the transmit modulation generated by the transmit
modulation signal 224 discussed above with reference to the
transmitter in FIG. 12.
[0098] The rectifier 318 is connected to switch S2B, which is
connected in series with resistor R2 and ground. The rectifier 318
also is connected to switch S3B. The other side of switch S3B
supplies a DC power signal 322 to a receive device (not shown) to
power the receive device, charge a battery, or a combination
thereof.
[0099] In FIGS. 13A-13C the DC impedance of the receive antenna 304
is changed by selectively coupling the receive antenna to ground
through switch S1B. In contrast, in the exemplary embodiments of
FIGS. 14A-14C, the impedance of the antenna can be modified to
generate the reverse link signaling by modifying the state of
switches S1B, S2B, and S3B to change the AC impedance of the
receive antenna 304. In FIGS. 14A-14C the resonant frequency of the
receive antenna 304 may be tuned with capacitor C2. Thus, the AC
impedance of the receive antenna 304 may be changed by selectively
coupling the receive antenna 304 through capacitor C1 using switch
S1B, essentially changing the resonance circuit to a different
frequency that will be outside of a range that will optimally
couple with the transmit antenna. If the resonance frequency of the
receive antenna 304 is near the resonant frequency of the transmit
antenna, and the receive antenna 304 is in the near-field of the
transmit antenna, a coupling mode may develop wherein the receiver
can draw significant power from the radiated field 106.
[0100] In FIG. 14A, switch S1B is closed, which de-tunes the
antenna and creates an "AC cloaking state," essentially "cloaking"
the receive antenna 304 from detection by the transmit antenna 204
because the receive antenna does not resonate at the transmit
antenna's frequency. Since the receive antenna will not be in a
coupled mode, the state of switches S2B and S3B are not
particularly important to the present discussion.
[0101] In FIG. 14B, switch S1B is open, switch S2B is closed, and
switch S3B is open, creating a "tuned dummy-load state" for the
receive antenna 304. Because switch S1B is open, capacitor C1 does
not contribute to the resonance circuit and the receive antenna 304
in combination with capacitor C2 will be in a resonance frequency
that may match with the resonant frequency of the transmit antenna.
The combination of switch S3B open and switch S2B closed creates a
relatively high current dummy load for the rectifier, which will
draw more power through the receive antenna 304, which can be
sensed by the transmit antenna. In addition, the transmit signal
320 can be detected since the receive antenna is in a state to
receive power from the transmit antenna.
[0102] In FIG. 14C, switch S1B is open, switch S2B is open, and
switch S3B is closed, creating a "tuned operating state" for the
receive antenna 304. Because switch S1B is open, capacitor C1 does
not contribute to the resonance circuit and the receive antenna 304
in combination with capacitor C2 will be in a resonance frequency
that may match with the resonant frequency of the transmit antenna.
The combination of switch S2B open and switch S3B closed creates a
normal operating state wherein power can be supplied by the DC out
signal 322 and a transmit signal 320 can be detected.
[0103] Reverse link signaling may be accomplished by switching
between the tuned operating state (FIG. 14C) and the AC cloaking
state (FIG. 14A). Reverse link signaling also may be accomplished
by switching between the tuned dummy-load state (FIG. 14B) and the
AC cloaking state (FIG. 14A). Reverse link signaling also may be
accomplished by switching between the tuned operating state (FIG.
14C) and the tuned dummy-load state (FIG. 14B) because there will
be a difference in the amount of power consumed by the receiver,
which can be detected by the load sensing circuit in the
transmitter.
[0104] Of course, those of ordinary skill in the art will recognize
that other combinations of switches S1B, S2B, and S3B may be used
to create cloaking, generate reverse link signaling and supplying
power to the receive device. In addition, the switches S1A and S1B
may be added to the circuits of FIGS. 14A-14C to create other
possible combinations for cloaking, reverse link signaling, and
supplying power to the receive device.
[0105] Thus, when in a coupled mode signals may be sent from the
transmitter to the receiver, as discussed above with reference to
FIG. 12. In addition, when in a coupled mode signals may be sent
from the receiver to the transmitter, as discussed above with
reference to FIGS. 13A-13C and 14A-14C.
[0106] FIGS. 15A-15D are simplified block diagrams illustrating a
beacon power mode for transmitting power between a transmitter and
a one or more receivers. FIG. 15A illustrates a transmitter 520
having a low power "beacon" signal 525 when there are no receive
devices in the beacon coupling-mode region 510. The beacon signal
525 may be, as a non-limiting example, such as in the range of
.about.10 to .about.20 mW RF. This signal may be adequate to
provide initial power to a device to be charged when it is placed
in the coupling-mode region.
[0107] FIG. 15B illustrates a receive device 530 placed within the
beacon coupling-mode region 510 of the transmitter 520 transmitting
the beacon signal 525. If the receive device 530 is on and develops
a coupling with the transmitter it will generate a reverse link
coupling 535, which is really just the receiver accepting power
from the beacon signal 525. This additional power, may be sensed by
the load sensing circuit 216 (FIG. 12) of the transmitter. As a
result, the transmitter may go into a high power mode.
[0108] FIG. 15C illustrates the transmitter 520 generating a high
power signal 525' resulting in a high power coupling-mode region
510'. As long as the receive device 530 is accepting power and, as
a result, generating the reverse link coupling 535, the transmitter
will remain in the high power state. While only one receive device
530 is illustrated, multiple receive devices 530 may be present in
the coupling-mode region 510. If there are multiple receive device
530 they will share the amount of power transmitted by the
transmitter based on how well each receive device 530 is coupled.
For example, the coupling efficiency may be different for each
receive device 530 depending on where the device is placed within
the coupling-mode region 510 as was explained above with reference
to FIGS. 8 and 9.
[0109] FIG. 15D illustrates the transmitter 520 generating the
beacon signal 525 even when a receive device 530 is in the beacon
coupling-mode region 510. This state may occur when the receive
device 530 is shut off, or the device cloaks itself, perhaps
because it does not need any more power.
[0110] The receiver and transmitter may communicate on a separate
communication channel (e.g., Bluetooth, zigbee, etc). With a
separate communication channel, the transmitter may determine when
to switch between beacon mode and high power mode, or create
multiple power levels, based on the number of receive devices in
the coupling-mode region 510 and their respective power
requirements.
[0111] Exemplary embodiments of the invention include enhancing the
coupling between a relatively large transmit antenna and a small
receive antenna in the near field power transfer between two
antennas through introduction of additional antennas into the
system of coupled antennas that will act as repeaters and will
enhance the flow of power from the transmitting antenna toward the
receiving antenna.
[0112] In exemplary embodiments, one or more extra antennas are
used that couple to the transmit antenna and receive antenna in the
system. These extra antennas comprise repeater antennas, such as
active or passive antennas. A passive antenna may include simply
the antenna loop and a capacitive element for tuning a resonant
frequency of the antenna. An active element may include, in
addition to the antenna loop and one or more tuning capacitors, an
amplifier for increasing the strength of a repeated near field
radiation.
[0113] The combination of the transmit antenna and the repeater
antennas in the power transfer system may be optimized such that
coupling of power to very small receive antennas is enhanced based
on factors such as termination loads, tuning components, resonant
frequencies, and placement of the repeater antennas relative to the
transmit antenna.
[0114] A single transmit antenna exhibits a finite near field
coupling mode region. Accordingly, a user of a device charging
through a receiver in the transmit antenna's near field coupling
mode region may require a considerable user access space that would
be prohibitive or at least inconvenient. Furthermore, the coupling
mode region may diminish quickly as a receive antenna moves away
from the transmit antenna.
[0115] A repeater antenna may refocus and reshape a coupling mode
region from a transmit antenna to create a second coupling mode
region around the repeater antenna, which may be better suited for
coupling energy to a receive antenna. Discussed below in FIGS.
16A-19B are some non-limiting examples of embodiments including
repeater antennas.
[0116] FIG. 16A illustrates a large transmit antenna 610A with a
smaller repeater antenna 620A disposed coplanar with, and within a
perimeter of, the transmit antenna 610A. The transmit antenna 610A
and repeater antenna 620A are both formed on a table 640, as a
non-limiting example. A device including a receive antenna 630A is
placed within the perimeter of the repeater antenna 620A. With very
large antennas, there may be areas of the coupling mode region that
are relatively week near the center of the transmit antenna 610A.
Presence of this weak region may be particularly noticeable when
attempting to couple to a very small receive antenna 630A. The
repeater antenna 620A placed coplanar with the transmit antenna
610A, but with a smaller size, may be able to refocus the coupling
mode region generated by the transmit antenna 610A into a smaller
and stronger repeated coupling mode region around the repeater
antenna 620A. As a result, a relatively strong repeated near field
radiation is available for the receive antenna 630A.
[0117] FIG. 16B illustrates a transmit antenna 610B with a larger
repeater antenna 620B with a coaxial placement relative to the
transmit antenna 610B. A device including a receive antenna 630B is
placed within the perimeter of the repeater antenna 620B. The
transmit antenna 610B is formed around the lower edge circumference
of a lamp shade 642, while the repeater antenna 620B is disposed on
a table 640. Recall that with coaxial placements, the near field
radiation may diminish relatively quickly relative to distance away
from the plane of an antenna. As a result, the small receive
antenna 630B placed in a coaxial placement relative to the transmit
antenna 610B may be in a weak coupling mode region. However, the
large repeater antenna 620B placed coaxially with the transmit
antenna 610B may be able to reshape the coupled mode region of the
transmit antenna 610B to another coupled mode region in a different
place around the repeater antenna 620B. As a result, a relatively
strong repeated near field radiation is available for the receive
antenna 630B placed coplanar with the repeater antenna 620B.
[0118] FIG. 17A illustrates a large transmit antenna 610C with
three smaller repeater antennas 620C disposed coplanar with, and
within a perimeter of, the transmit antenna 610C. The transmit
antenna 610C and repeater antennas 620C are formed on a table 640.
Various devices including receive antennas 630C are placed at
various locations within the transmit antenna 610C and repeater
antennas 620C. As with the exemplary embodiment illustrated in FIG.
16A, the exemplary embodiment of FIG. 17A may be able to refocus
the coupling mode region generated by the transmit antenna 610C
into smaller and stronger repeated coupling mode regions around
each of the repeater antennas 620C. As a result, a relatively
strong repeated near field radiation is available for the receive
antennas 630C. Some of the receive antennas are placed outside of
any repeater antennas 620C. Recall that the coupled mode region may
extend somewhat outside the perimeter of an antenna. Therefore,
receive antennas 630C may be able to receive power from the near
field radiation of the transmit antenna 610C as well as any nearby
repeater antennas 620C. As a result, receive antennas placed
outside of any repeater antennas 620C, may be still be able to
receive power from the near field radiation of the transmit antenna
610C as well as any nearby repeater antennas 620C.
[0119] FIG. 17B illustrates a large transmit antenna 610D with
smaller repeater antennas 620D with offset coaxial placements and
offset coplanar placements relative to the transmit antenna 610D. A
device including a receive antenna 630D is placed within the
perimeter of one of the repeater antennas 620D. As a non-limiting
example, the transmit antenna 610D may be disposed on a ceiling
646, while the repeater antennas 620D may be disposed on a table
640. As with the exemplary embodiment of FIG. 16B, the repeater
antennas 620D in an offset coaxial placement may be able to reshape
and enhance the near field radiation from the transmitter antenna
610D to repeated near field radiation around the repeater antennas
620D. As a result, a relatively strong repeated near field
radiation is available for the receive antenna 630D placed coplanar
with the repeater antennas 620D.
[0120] While the various transmit antennas and repeater antennas
have been shown in general on surfaces, these antennas may also be
disposed under surfaces (e.g., under a table, under a floor, behind
a wall, or behind a ceiling), or within surfaces (e.g., a table
top, a wall, a floor, or a ceiling).
[0121] FIG. 18 shows simulation results indicating coupling
strength between a transmit antenna, a repeater antenna and a
receive antenna. The transmit antenna, the repeater antenna, and
the receive antenna are tuned to have a resonant frequency of about
13.56 MHz.
[0122] Curve 662 illustrates a measure for the amount of power
transmitted from the transmit antenna out of the total power fed to
the transmit antenna at various frequencies. Similarly, curve 664
illustrates a measure for the amount of power received by the
receive antenna through the repeater antenna out of the total power
available in the vicinity of its terminals at various frequencies.
Finally, Curve 668 illustrates the amount of power actually coupled
between the transmit antenna, through the repeater antenna and into
the receive antenna at various frequencies.
[0123] At the peak of curve 668, corresponding to about 13.56 MHz,
it can be seen that a large amount of the power sent from the
transmitter is available at the receiver, indicating a high degree
of coupling between the combination of the transmit antenna, the
repeater antenna and the receive antenna.
[0124] FIG. 19A show simulation results indicating coupling
strength between a transmit antenna and receive antenna disposed in
a coaxial placement relative to the transmit antenna with no
repeater antennas. The transmit antenna and the receive antenna are
tuned to have a resonant frequency of about 10 MHz. The transmit
antenna in this simulation is about 1.3 meters on a side and the
receive antenna is a multi-loop antenna at about 30 mm on a side.
The receive antenna is placed at about 2 meters away from the plane
of the transmit antenna. Curve 682A illustrates a measure for the
amount of power transmitted from the transmit antenna out of the
total power fed to its terminals at various frequencies. Similarly,
curve 684A illustrates a measure of the amount of power received by
the receive antenna out of the total power available in the
vicinity of its terminals at various frequencies. Finally, Curve
686A illustrates the amount of power actually coupled between the
transmit antenna and the receive antenna at various
frequencies.
[0125] FIG. 19B show simulation results indicating coupling
strength between the transmit and receive antennas of FIG. 19A when
a repeater antenna is included in the system. The transmit antenna
and receive antenna are the same size and placement as in FIG. 19A.
The repeater antenna is about 28 cm on a side and placed coplanar
with the receive antenna (i.e., about 0.1 meters away from the
plane of the transmit antenna). In FIG. 19B, Curve 682B illustrates
a measure of the amount of power transmitted from the transmit
antenna out of the total power fed to its terminals at various
frequencies. Curve 684B illustrates the amount of power received by
the receive antenna through the repeater antenna out of the total
power available in the vicinity of its terminals at various
frequencies. Finally, Curve 686B illustrates the amount of power
actually coupled between the transmit antenna, through the repeater
antenna and into the receive antenna at various frequencies.
[0126] When comparing the coupled power (686A and 686B) from FIGS.
19A and 19B it can be seen that without a repeater antenna the
coupled power 686A peaks at about -36 dB. Whereas, with a repeater
antenna the coupled power 686B peaks at about -5 dB. Thus, near the
resonant frequency, there is a significant increase in the amount
of power available to the receive antenna due to the inclusion of a
repeater antenna.
[0127] Exemplary embodiments of the invention include low cost
unobtrusive ways to properly manage how the transmitter radiates to
single and multiple devices and device types in order to optimize
the efficiency by which the transmitter conveys charging power to
the individual devices.
[0128] Exemplary embodiments of the invention include low cost
unobtrusive ways to properly manage how the transmitter radiates to
single and multiple devices and device types in order to optimize
the efficiency by which the transmitter conveys charging power to
the individual devices
[0129] FIG. 20 is a simplified block diagram of a transmitter 200
for use in furniture and buildings. The transmitter is similar to
that of FIG. 10 and, therefore, does not need to be explained
again. However, in FIG. 20 the transmitter 200 may include a
presence detector 280, and enclosed detector 290, or a combination
thereof, connected to the controller 214 (also referred to as a
processor herein). The controller 214 can adjust an amount of power
delivered by the amplifier 210 in response to presence signals from
the presence detector 280 and enclosed detector 290. The
transmitter may receive power through an AC-DC converter (not
shown) to convert conventional AC power present in a building
299.
[0130] As a non-limiting example, the presence detector 280 may be
a motion detector utilized to sense the initial presence of a
device to be charged that is inserted into the coverage area of the
transmitter. After detection, the transmitter is turned on and the
RF power received by the device is used to toggle a switch on the
Rx device in a pre-determined manner, which in turn results in
changes to the driving point impedance of the transmitter.
[0131] As another non-limiting example, the presence detector 280
may be a detector capable of detecting a human, for example, by
infrared detection, motion detection, or other suitable means. In
some exemplary embodiments, there may be regulations limiting the
amount of power that a transmit antenna may transmit at a specific
frequency. In some cases, these regulations are meant to protect
humans from electromagnetic radiation. However, there may be
environments where transmit antennas are placed in areas not
occupied by humans, or occupied infrequently by humans, such as,
for example, garages, factory floors, shops, and the like. If these
environments are free from humans, it may be permissible to
increase the power output of the transmit antennas above the normal
power restrictions regulations. In other words, the controller 214
may adjust the power output of the transmit antenna 204 to a
regulatory level or lower in response to human presence and adjust
the power output of the transmit antenna 204 to a level above the
regulatory level when a human is outside a regulatory distance from
the electromagnetic field of the transmit antenna 204.
[0132] As a non-limiting example, the enclosed detector 290 (may
also be referred to herein as a enclosed furnishing detector) may
be a device such as a sense switch for determining when an
enclosure is in a closed or open state, as is explained more fully
below. In many of the examples below, only one guest device is
shown being charged. In practice, a multiplicity of the devices can
be charged from a hot spot generated by each host.
[0133] In exemplary embodiments, a method by which the Tx circuit
does not remain on indefinitely may be used. In this case, the Tx
circuit may be programmed to shut off after a user-determined
amount of time. This feature prevents the Tx circuit, notably the
power amplifier, from running long after the wireless devices in
its perimeter are fully charged. This event may be due to the
failure of the circuit to detect the signal sent from either the
repeater or the Rx coil that a device is fully charged. To prevent
the Tx circuit from automatically shutting down if another device
is placed in its perimeter, the Tx circuit automatic shut off
feature may be activated only after a set period of no motion
detected in its perimeter. The user may be able to determine the
inactivity time interval, and change it as desired. As a
non-limiting example, the time interval may be longer than that
needed to fully charge a specific type of wireless device under the
assumption of the device being initially fully discharged.
[0134] Exemplary embodiments of the invention include using
furnishing and elements in buildings such as walls, ceilings, and
floors to bear power transmitting devices housing totally, or
partially, the transmit antenna and other circuitry necessary for
wireless transfer of power to other often smaller devices.
[0135] The power transmitting devices may be partially or fully
embedded in the aforementioned furnishings and building elements,
such as at the time of manufacture. Such furnishings and building
elements are referred to herein as host furnishings.
[0136] The power transmitting devices may also be retrofitted into
existing furnishings and building elements by attaching the
transmit antenna thereto. Such furnishings and building elements
are referred to herein as existing furniture items. In this
context, attachment may mean affixing the antenna to a furnishing
or building element, such as, for example, a wall or the underside
of a shelf so the transmit antenna is held in place. Attachment may
also mean simply placing the transmit antenna in a position where
it will naturally be held in place, such as, for example, in the
bottom of a drawer or on a shelf.
[0137] Electrically small antennas have low efficiency, often no
more than a few percent as explained by the theory of small
antennas. The smaller the electric size of an antenna, the lower is
its efficiency. The wireless power transfer can become a viable
technique replacing wired connection to the electric grid in
industrial, commercial, and household applications if power can be
sent over meaningful distances to the devices that are in the
receiving end of such power transfer system. While this distance is
application dependent, a few tens of a centimeter to a few meters
can be deemed a suitable range for most applications. Generally,
this range reduces the effective frequency for the electric power
in the interval between 5 MHz to 100 MHz.
[0138] Exemplary embodiments of the invention include converting a
variety of the furnishings and building elements around the house,
in the office, and in other buildings to hosts that can transfer
electric power wirelessly to guest devices either to charge their
rechargeable batteries or to directly feed them.
[0139] FIGS. 21 and 22 are plan views of block diagrams of a
multiple transmit antenna wireless charging apparatus, in
accordance with exemplary embodiments. As stated, locating a
receiver in a near field coupling mode region of a transmitter for
engaging the receiver in wireless charging may be unduly burdensome
by requiring accurate positioning of the receiver in the transmit
antenna's near field coupling mode region. Furthermore, locating a
receiver in the near field coupling mode region of a fixed-location
transmit antenna may also be inaccessible by a user of a device
coupled to the receiver especially when multiple receivers are
respectively coupled to multiple user accessible devices (e.g.,
laptops, PDAs, wireless devices) where users need concurrent
physical access to the devices. For example, a single transmit
antenna exhibits a finite near field coupling mode region.
[0140] Accordingly, a user of a device charging through a receiver
in the transmit antenna's near field coupling mode region may
require a considerable user access space that would be prohibitive
or at least inconvenient for another user of another device to also
wirelessly charge within the same transmit antenna's near field
coupling mode region and also require separate user access space.
For example, two adjacent users of wireless chargeable devices
seated at a conference table configured with a single transmit
antenna may be inconvenienced or prohibited from accessing their
respective devices due to the local nature of the transmitters near
field coupling mode region and the considerable user access space
required to interact with the respective devices. Additionally,
requiring a specific wireless charging device and its user to be
specifically located may also inconvenience a user of the
device.
[0141] Referring to FIG. 21, an exemplary embodiment of a multiple
transmit antenna wireless charging apparatus 700 provides for
placement of a plurality of adjacently located transmit antenna
circuits 702A-702D to define an enlarged wireless charging region
708. By way of example and not limitation, a transmit antenna
circuit includes a transmit antenna 710 having a diameter or side
dimension, for example, of around 30-40 centimeters for providing
uniform coupling to an receive antenna (not shown) that is
associated with or fits in an electronic device (e.g., wireless
device, handset, PDA, laptop, etc.). By considering the transmit
antenna circuit 702 as a unit or cell of the multiple transmit
antenna wireless charging apparatus 700, stacking or adjacently
tiling these transmit antenna circuits 702A-702D next to each
other, for example, on substantially a single planar surface 704
(e.g., on a table top) allows for reorienting or increasing the
charging region. The enlarged wireless charging region 708 results
in an increased charging region for one or more devices.
[0142] The multiple transmit antenna wireless charging apparatus
700 further includes a transmit power amplifier 720 for providing
the driving signal to transmit antennas 710. In configurations
where the near field coupling mode region of one transmit antenna
710 interferes with the near field coupling mode regions of other
transmit antennas 710, the interfering adjacent transmit antennas
710 are "cloaked" to allow improved wireless charging efficiency of
the activated transmit antenna 710.
[0143] The sequencing of activation of transmit antennas 710 in
multiple transmit antenna wireless charging apparatus 700 may occur
according to a time-domain based sequence. The output of transmit
power amplifier 720 is coupled to a multiplexer 722 which
time-multiplexes, according to control signal 724 from the
transmitter processor, the output signal from the transmit power
amplifier 720 to each of the transmit antennas 710.
[0144] In order to inhibit inducing resonance in adjacent inactive
transmit antenna 710 when the power amplifier 720 is driving the
active transmit antenna, the inactive antennas may be "cloaked" by
altering the resonant frequency of that transmit antenna by, for
example, activating the cloaking circuit 714. By way of
implementation, concurrent operation of directly or nearly adjacent
transmit antenna circuits 702 may result in interfering effects
between concurrently activated and physically nearby or adjacent
other transmit antenna circuits 702. Accordingly, transmit antenna
circuit 702 may further include a transmitter cloaking circuit 714
for altering the resonant frequency of transmit antennas 710.
[0145] The transmitter cloaking circuit may be configured as a
switching means (e.g. a switch) for shorting-out or altering the
value of reactive elements, for example capacitor 716, of the
transmit antenna 710. The switching means may be controlled by
control signals 721 from the transmitter's processor. In operation,
one of the transmit antennas 710 is activated and allowed to
resonate while other of transmit antennas 710 are inhibited from
resonating, and therefore inhibited from adjacently interfering
with the activated transmit antenna 710. Accordingly, by
shorting-out or altering the capacitance of a transmit antenna 710,
the resonant frequency of transmit antenna 710 is altered to
prevent resonant coupling from other transmit antennas 710. Other
techniques for altering the resonant frequency are also
contemplated.
[0146] In another exemplary embodiment, each of the transmit
antenna circuits 702 can determine the presence or absence of
receivers within their respective near field coupling mode regions
with the transmitter processor choosing to activate ones of the
transmit antenna circuits 702 when receivers are present and ready
for wireless charging or forego activating ones of the transmit
antenna circuits 702 when receivers are not present or not ready
for wireless charging in the respective near field coupling mode
regions. The detection of present or ready receivers may occur
according to the receiver detection signaling protocol described
herein or may occur according to physical sensing of receivers such
as motion sensing, pressure sensing, image sensing or other sensing
techniques for determining the presence of a receiver within a
transmit antenna's near field coupling mode region. Furthermore,
preferential activation of one or more transmit antenna circuits by
providing an enhanced proportional duty cycle to at least one of
the plurality of antenna circuits is also contemplated to be within
the scope of the present invention.
[0147] Referring to FIG. 22, an exemplary embodiment of a multiple
transmit antenna wireless charging apparatus 800 provides for
placement of a plurality of adjacently located repeater antenna
circuits 802A-802D inside of a transmit antenna 801 defining an
enlarged wireless charging region 808. Transmit antenna 801, when
driven by transmit power amplifier 820, induces resonant coupling
to each of the repeater antennas 810A-810D. By way of example and
not limitation, a repeater antenna 810 having a diameter or side
dimension, for example, of around 30-40 centimeters provides
uniform coupling to a receive antenna (not shown) that is
associated with or affixed to an electronic device. By considering
the repeater antenna circuit 802 as a unit or cell of the multiple
transmit antenna wireless charging apparatus 800, stacking or
adjacently tiling these repeater antenna circuits 802A-802D next to
each other on substantially a single planar surface 804 (e.g., on a
table top) allows for increasing or enlarging the charging region.
The enlarged wireless charging region 808 results in an increased
charging space for one or more devices.
[0148] The multiple transmit antenna wireless charging apparatus
800 includes transmit power amplifier 820 for providing the driving
signal to transmit antenna 801. In configurations where the near
field coupling mode region of one repeater antenna 810 interferes
with the near field coupling mode regions of other repeater
antennas 810, the interfering adjacent repeater antennas 810 are
"cloaked" to allow improved wireless charging efficiency of the
activated repeater antenna 810.
[0149] The sequencing of activation of repeater antennas 810 in
multiple transmit antenna wireless charging apparatus 800 may occur
according to a time-domain based sequence. The output of transmit
power amplifier 820 is generally constantly coupled (except during
receiver signaling as described herein) to transmit antenna 801. In
the present exemplary embodiment, the repeater antennas 810 are
time-multiplexed according to control signals 821 from the
transmitter processor. By way of implementation, concurrent
operation of directly or nearly adjacent repeater antenna circuits
802 may result in interfering effects between concurrently
activated and physically nearby or adjacent other repeater antennas
circuits 802. Accordingly, repeater antenna circuit 802 my further
include a repeater cloaking circuit 814 for altering the resonant
frequency of repeater antennas 810.
[0150] The repeater cloaking circuit may be configured as a
switching means (e.g. a switch) for shorting-out or altering the
value of reactive elements, for example capacitor 816, of the
repeater antenna 810. The switching means may be controlled by
control signals 821 from the transmitter's processor. In operation,
one of the repeater antennas 810 is activated and allowed to
resonate while other of repeater antennas 810 are inhibited from
resonating, and therefore adjacently interfering with the activated
repeater antenna 810. Accordingly, by shorting-out or altering the
capacitance of a repeater antenna 810, the resonant frequency of
repeater antenna 810 is altered to prevent resonant coupling from
other repeater antennas 810. Other techniques for altering the
resonant frequency are also contemplated.
[0151] In another exemplary embodiment, each of the repeater
antenna circuits 802 can determine the presence or absence of
receivers within their respective near field coupling mode regions
with the transmitter processor choosing to activate ones of the
repeater antenna circuits 802 when receivers are present and ready
for wireless charging or forego activating ones of the repeater
antenna circuits 802 when receivers are not present or not ready
for wireless charging in the respective near field coupling mode
regions. The detection of present or ready receivers may occur
according to the receiver detection signaling protocol described
herein or may occur according to physical sensing of receivers such
as motion sensing, pressure sensing, image sensing or other sensing
techniques for determining a receiver to be within a repeater
antenna's near field coupling mode region.
[0152] The various exemplary embodiments of the multiple transmit
antenna wireless charging apparatus 700 and 800 may further include
time domain multiplexing of the input signal being coupled to
transmit/repeater antennas 710, 810 based upon asymmetrically
allocating activation time slots to the transmit/repeater antennas
based upon factors such as priority charging of certain receivers,
varying quantities of receivers in different antennas' near field
coupling mode regions, power requirements of specific devices
coupled to the receivers as well as other factors.
[0153] As stated, efficient transfer of energy between the
transmitter and receiver occurs during matched or nearly matched
resonance between the transmitter and the receiver. However, even
when resonance between the transmitter and receiver are not
matched, energy may be transferred at a lower efficiency. Transfer
of energy occurs by coupling energy from the near-field of the
transmitting antenna to the receiving antenna residing in the
neighborhood where this near-field is established rather than
propagating the energy from the transmitting antenna into free
space.
[0154] It should be noted that the foregoing approach is applicable
to variety of communication standards such as CDMA, WCDMA, OFDM etc
Those of skill in the art would understand that information and
signals may be represented using any of a variety of different
technologies and techniques. For example, data, instructions,
commands, information, signals, bits, symbols, and chips that may
be referenced throughout the above description may be represented
by voltages, currents, electromagnetic waves, magnetic fields or
particles, optical fields or particles, or any combination
thereof.
[0155] FIGS. 21 and 22 illustrate multiple loops in a charging
region that is substantially planar. However, embodiments of the
present invention are not so limited. In the exemplary embodiments
described herein, multi-dimensional regions with multiple antennas
may be performed by the techniques described herein. In addition,
multi-dimensional wireless powering and charging may be employed,
such as the means described in U.S. patent application Ser. No.
12/567,339, entitled "SYSTEMS AND METHOD RELATING TO
MULTI-DIMENSIONAL WIRELESS CHARGING" filed on Sep. 25, 2009, the
contents of which are hereby incorporated by reference in its
entirety for all purposes.
[0156] When placing one or more devices in a wireless charging
apparatus (e.g. near-field magnetic resonance, inductive coupling,
etc.) the orientation between the receiver and the wireless
charging apparatus transmit antenna(s) may vary. For example, when
charging a medical device while disinfecting it in a solution bath
or when charging tools while working under water. When a device is
dropped into a container with fluid inside, the angle in which the
device lands on the bottom of the container would depend on the way
its mass is distributed. As another non-limiting example, when the
wireless charging apparatus takes the form of a box or a bowl,
careless placement of the device, while convenient, may not
guarantee the useful positioning of the device with respect to the
wireless charging apparatus. The wireless charging apparatus may
also be integrated into a large container or cabinet that can hold
many devices, such as a tool storage chest, a toy chest, or an
enclosure designed specifically for wireless charging. The receiver
integration into these devices may be inconsistent because the
devices have different form factors and may be placed in different
orientations relative to the wireless power transmitter.
[0157] Existing designs of wireless charging apparatus may perform
best under a predefined orientation and deliver lower power levels
if the orientation between the wireless charging apparatus and the
receiver is different. In addition, when the charged device is
placed in a position where only a portion of the wireless power can
be delivered, charging times may increase. Some solutions may
design the wireless charging apparatus in a way that requires a
user to place the device in a special cradle or holder that
positions the device to be charged in an advantageous orientation,
resulting in a loss of convenience to the user.
[0158] Other approaches are based on inductive coupling between a
transmit antenna embedded, for example, in a "charging" mat or
surface and a receive antenna plus rectifying circuit embedded in
the host device to be charged. In this approach the spacing between
transmit and receive antennas generally must be very close (e.g.,
several millimeters).
[0159] In addition, it is desirable to have wireless power
available in places most used by the users for placement of their
device to be charged, to enable users to charge their device more
conveniently. Many users prefer storing objects in containers or
inside furniture as part of maintaining their home or workplace
organized. Sometimes they put the devices in the storage space
while they are inside a bag, a pocket or a package (e.g. in a
retail store). However, given the need to maintain the devices
charged the user has to deal with taking them out and charging
them. The user may also forget to charge these devices and be
subject to delay when the devices are actually needed.
[0160] FIGS. 23A-23C illustrate an exemplary embodiment of an item
bearing transmit antennas oriented in multiple directions. This
multi-dimension orientation may increase the power that can be
delivered to the receiver positioned in various orientations in
respect to the multiple dimensions of the transmit antenna(s).
[0161] In FIGS. 23A-23C, a three-dimensional wireless charging
apparatus is shown in which the transmit antenna(s) are embedded in
approximately orthogonal surfaces along the X, Y, and Z axes. The
surfaces can be for example, three sides of a rectangular
enclosure. Flexibility is provided so that any one of the three Tx
antennas, any pair of them, or all three at once can be used to
wirelessly provide RF power to the Rx antenna in a device placed
within the enclosure. A means such as that discussed above with
respect to FIGS. 21 and 22 may be used for selecting and
multiplexing between the differently oriented antennas.
[0162] In FIGS. 23A-23C, an exemplary tool 930 is disposed in a
tool box 910. A first-orientation transmit antenna 912 is disposed
on a bottom of the tool box 910. A second-orientation transmit
antenna 914 is disposed on a first side of the tool box 910 and a
third-orientation transmit antenna 916 is disposed on a second side
of the tool box 910 and substantially orthogonal to the
second-orientation transmit antenna 914. FIG. 23A illustrates the
tool box 910 with the lid open to show the tool 930 disposed
therein. FIG. 23B illustrates the tool box 910 with the lid
closed.
[0163] FIG. 23C illustrates an alternate configuration of a
continuous loop transmit antenna 920 that includes multiple facets
in substantially orthogonal directions. If the exemplary embodiment
of FIG. 23C, the continuous loop transmit antenna 920 includes a
first facet 922 along the bottom of the tool box 910, a second
facet 924 along a side of the tool box 910, and a third facet 926
along the back of the tool box 910.
[0164] In a small wireless charging apparatus, there maybe only one
transmitter in each dimension. In a large wireless charging
apparatus, where the parallel panels are sufficiently far from each
other to prevent interference, a transmitter may be set on the
opposite panels so that devices placed in the middle between them
can get power from both directions.
[0165] FIGS. 24A and 24B illustrate an exemplary embodiment of a
cabinet 950 bearing transmit antennas oriented in multiple
directions with transmit antennas in opposite panels. FIG. 24A
shows the cabinet 950 with an open door and FIG. 24B shows the
cabinet 950 with the door closed.
[0166] Transmit antennas 972 and 974 are on opposing sides (i.e.,
the left and the right respectively) of the cabinet 950. Transmit
antennas 962 and 964 are on opposing sides (i.e., the door and the
back respectively) of the cabinet 950. Transmit antennas 982 and
984 are on opposing sides (i.e., the top and the bottom
respectively) of the cabinet 950.
[0167] Referring to FIGS. 23A-24B, a self-calibrating method that
defines the optimal selection of Tx antennas leading to the highest
power received by the device may be provided. If multiple devices
are to be charged in the same enclosure, a means to assign a
different selection of Tx antennas to each device is possible by
assigning different time slots to each device.
[0168] In an exemplary embodiment, the frequency of operations is
chosen to be low enough such the reasonably-sized Tx antennas are
within the near field regions of each other. This allows for much
higher coupling levels (-1.5 to -3 dB) than would be possible if
the antennas were spaced farther apart. The orthogonality of the
surfaces the embedded Tx antennas results in the electromagnetic
fields radiated by them to be approximately orthogonally polarized
which in turn improves the isolation between them so that the power
lost due to unwanted coupling is reduced. Allowing the power
transmitted from each Tx antenna to be intelligently selectable
allows for the reduction efficiency losses due to polarization
mismatch between the ensemble of Tx and the arbitrarily placed Rx
antenna.
[0169] In an exemplary embodiment, each Rx device and Tx antenna
may utilize techniques for signaling between them described in
above with respect to FIGS. 13A-15D. In addition, more
sophisticated signaling means may be employed, such as the means
described in U.S. patent application Ser. No. 12/249,816, entitled
"SIGNALING CHARGING IN WIRELESS POWER ENVIRONMENT" filed on Oct.
10, 2008, the contents of which is hereby incorporated herein in
its entirety by reference.
[0170] These signaling methods can be used during a "calibration
period," in which power is transmitted for all each possible
combination of Tx antennas in sequence and the Rx signals back
which results the highest power received. The Tx system can then
begin the charging period using this optimum combination of Tx
antennas. For charging multiple, arbitrarily-oriented devices in
the same enclosure, the signaling scheme allows the Tx system to
assign a device a time slot of duration of 1/N times T where N is
the number of units being charged and T is the charging period.
During its time slot, the Rx device can determine the optimum
combination of Tx antennas for best power transfer, independent of
the combination desired for the other Rx devices. This is not to
say that time slotting is required for optimum power transfer to
multiple devices. It is possible for instance, that the relative
orientations of two Rx devices are such that the polarizations of
their antennas are orthogonal to each other (e.g., X-Y plane for
device A, Y-Z plane for device B). In this case, the optimum Tx
antenna configuration would be to use the Tx antenna oriented in
the X-Y plane for device A and the Tx antenna in the Y-Z plane for
device B. Due to the inherent isolation between the two Tx
antennas, it may be possible to charge them simultaneously. The
intelligent nature of the Tx antenna selection by each Rx device
allows for such a circumstance.
[0171] Exemplary embodiments of the invention include converting a
variety of the equipment around the house, office, and other
buildings to hosts with transmitters, repeaters, or a combination
thereof that can transfer electric power wirelessly to guest
devices with receivers either to charge their rechargeable
batteries or to directly feed them. This equipment may be generally
referred to herein as host furnishings and existing furniture
items. Thus, these host furnishings can provide several hot spots
in the environment where the hosts are located for wireless
transfer of power to guest devices without having to establish
independent infrastructure for wireless transmission of electric
power. These exemplary embodiments may not require a large transmit
antenna, which is often more difficult to blend into the decor of
the environment and may not be as esthetically acceptable. In
addition, larger antennas may generate larger electromagnetic (EM)
fields and it may be harder to comply with safety issues.
[0172] Exemplary embodiments disclosed may use transmit antennas in
host furnishings as well as extra antennas such as repeaters in the
same or other host furnishings. These repeaters could be fed with
electric power or they could be passively terminated. The
combination of the repeaters and the coupled antennas in the power
transfer system can be optimized such that coupling of power to
very small Rx antennas is enhanced. The termination load and tuning
component in the repeaters could also be used to optimize the power
transfers in a system.
[0173] Exemplary embodiments of the disclosure include means for
charging low power receiver devices such as: eBooks, wireless
digital photo frames, smoke alarms and remote controls. This device
may charge at a very low power level when left in a users home,
office or any location that power transmitting devices may be
found. These receiver devices can be charged for a long period of
time with a low level of wireless power and always have sufficient
power to operate. Thus, a wireless digital photo frame may be
enabled that hung on a wall without any wired power provided. In
the exemplary embodiment of a smoke alarms, these devices could be
charged in the same way as above with no need for hard wired
electrical power. In the exemplary embodiment of remote controls:
As above these devices could be charged anywhere where the wireless
power could penetrate at a low rate. Other low power devices found
in the home, office, work environment, public areas, etc could use
the same methodology.
[0174] FIGS. 25-32 illustrate exemplary furnishings, storage
spaces, and building elements in which exemplary embodiments of the
invention can be practiced. For exemplary purposes, furniture such
as tables, shelves, drawers, etc is used herein, as well as
containers such as closets, cupboards, cubby holes, drawers,
locker, etc but it is understood that the exemplary embodiments of
the invention are not limited to such.
[0175] The wireless charging can be implemented, for example, using
inductive coupling, near field magnetic resonance power energy
transfer, etc. The transmitter can be integrated (built in), laid
over or attached to one or more internal surfaces (shelf, side
panel, back panel, upper panel, etc). The receiver is connected to
the electronic device as an accessory or is integrated into it.
[0176] In the inductive coupling implementation, there may be a
designated spot, active area, slot, shelf, groove or holder where a
primary coil is integrated or set using an overlaying pad attached
to the internal panel of the storage area. The charged device is
placed in this designated location to align the receiving coil with
the transmitting coil.
[0177] In the near field magnetic resonance implementation, the
transmitting loop can be added to one or multiple internal surfaces
of the storage area. When adding to one surface the charged device
can be placed in parallel to that surface and may be charged within
a short distance from it (depending on the power level that is
transmitted). For example a charging pad can be laid on the bottom
of the top drawer or top shelf and charge devices placed in the top
drawer or on top shelf and in the drawer or shelf below it,
depending on how far below they are and the level of power
transmitted. The charged device with the receiver can be placed
anywhere within the transmitting loop boundaries. The transmitting
loop layout in the storage area may be such that it would prevent
users from placing the charged device on its boundaries. Adding to
multiple surfaces provides further flexibility in the orientation
of the charged device as explained above with reference to FIGS.
23A-24B. These multi-orientation transmit antennas may be
especially helpful if the receiver device is placed inside a
storage area that contains other items on top of each other (e.g. a
drawer) or inside a bag (e.g. in a cubby hole or a locker).
[0178] FIGS. 25 and 26 illustrate a wirelessly charging surface,
such as on a table using an omni-directional transmit antenna where
a wireless charging apparatus with one coil charges devices both
above and below the coil. For example, such a wireless charging
apparatus could charge devices both on or near the surface of a
nightstand and within the top drawer of the nightstand
simultaneously. Omni-directional charging would allow more devices
to charge simultaneously than a uni-directional wireless charging
apparatus. This omni-directional charging solution broadens the
likelihood of a match between user behavior and the operation of a
wireless charging apparatus. Any of these exemplary embodiments and
other embodiments within the scope of the present invention may use
the presence detector 280 discussed above with reference to FIG.
20.
[0179] In addition, any of these exemplary embodiments and other
embodiments within the scope of the present invention that have an
enclosed region may use the enclosed detector 290 discussed above
with reference to FIG. 20 for determining whether the furnishing is
in an enclosed state or an open state. When in an enclosed state,
enhanced power levels may be possible. The enclosed detector 290
may be any sensor capable of detecting an enclosed state, such as,
for example, a switch on a door or drawer.
[0180] The wireless charging apparatus may receive power from a
standard home electrical outlet. The wireless charging apparatus
transmit antenna would be placed underneath or within the topmost
surface of a table or similar type of furniture. Such an
omni-directional charging mechanism could reduce the number of
wireless charging apparatus a household needs to purchase and make
wireless charging more cost effective for consumers. A wireless
charging shelf would allow consumers to charge consumer electronic
devices, capable of receiving a wireless charge, simply by leaving
the consumer electronic device on, or in, the shelf. In addition,
the shelf can be retrofit, with a wireless charging apparatus that
allows for a RF front end that facilitates changes in the size and
shape of the charging antenna-coil so that a wireless charging
design can easily be retro-fitted to a variety of existing
furniture. By enabling the RF front end to be swapped out, and
changed easily, this allows all-kinds of non-metallic furniture and
props to become wireless charging apparatus.
[0181] Wireless charging antenna-coils (plus the appropriate
matching circuitry) may be embodied as transmitting antennas or
repeater antennas as discussed above. Thus, the antennas may be
used in discrete sizes and shapes enabling normal furniture to be
up-graded to become furniture that can wirelessly charge electronic
devices. In addition to having a variety of discrete diameter sizes
for the antenna coil, the antenna coil could also be made in a
number of different shapes so that it fit round/square/rectangular
shaped furniture properly. These stick on charging antenna-coils
could be stuck on or attached to existing furniture in a manner
that is easily accomplished by an end user.
[0182] FIG. 25 illustrates an exemplary embodiment of a transmit
antenna 1015 disposed in or on a table 1010. In this exemplary
embodiment, the transmit antenna 1015 may be originally
manufactured as part of the table 1010 (i.e., a host furnishing) or
the transmit antenna 1015 may be disposed on the table (for example
in a drawer or underneath) afterwards (i.e., an existing furniture
item).
[0183] FIG. 26 illustrates an exemplary embodiment of a transmit
antenna 1025 in or on a shelf 1020 bearing a receiver device 1029.
In this exemplary embodiment, the transmit antenna 1025 may be
originally manufactured as part of the shelf 1020 (i.e., a host
furnishing) or the transmit antenna 1025 may be disposed on the
shelf 1020 afterwards (i.e., an existing furniture item).
[0184] FIG. 27 illustrates an exemplary embodiment of one or more
transmitters 1035 disposed in or on a bureau 1030. In this
exemplary embodiment, the transmit antennas 1035 may be originally
manufactured as part of the bureau 1030 (i.e., a host furnishing)
or the transmit antennas 1035 may be disposed in or on the bureau
1030 afterwards (i.e., an existing furniture item). As non-limiting
examples, the transmit antennas 1035 may be disposed in a bottom of
a drawer 1032, on the sides of the drawer 1032, and on the sides of
the bureau 1030. With multiple antennas (such as transmit or
repeater), the exemplary embodiments discussed above with reference
to FIGS. 21-24B can control the multiple antennas depending on
whether the antennas are coplanar (such as in FIGS. 21 and 22) or
are multi-dimensional (such as in FIGS. 23A-24B). Receiver devices
may be charged by haphazard placement of the receiver devices the
drawer while closing the drawer may permit the power level to be
further increased.
[0185] FIG. 28 illustrates an exemplary embodiment of a transmitter
antenna 1045 disposed in or on a drawer 1042 of a desk 1040. In
this exemplary embodiment, the transmit antenna 1045 may be
originally manufactured as part of the bureau 1040 (i.e., a host
furnishing) or the transmit antennas 1045 may be disposed in or on
the drawer 1042 afterwards (i.e., an existing furniture item).
Receiver devices 1049 may be charged by haphazard placement of the
receiver devices the drawer 1042 while closing the drawer may
permit the power level to be further increased
[0186] FIGS. 29A-29C illustrates an exemplary embodiment of an
enclosure 1050 bearing one or more transmitters 1055 in various
configurations. In these exemplary embodiments, the transmit
antennas 1055 may be originally manufactured as part of the
enclosure 1050 (i.e., a host furnishing) or the transmit antennas
1055 may be disposed in or on the enclosure 1050 afterwards (i.e.,
an existing furniture item). The enclosure 1050 may be specifically
designed as a charging enclosure. However, other multi-function
enclosures, such as, for example, school lockers and gym lockers
may also be used.
[0187] FIG. 29A illustrates a transmit antenna 1055 disposed in a
bottom of the enclosure 1050 with a receiver device 1059 within the
enclosure 1050. FIG. 29B shows multiple antennas 1055 on various
sides of the enclosure 1050 with a receiver device 1059 within the
enclosure 1050 and a receiver device 1059, within a handbag, within
the enclosure 1050. With multiple antennas (such as transmit or
repeater), the exemplary embodiments discussed above with reference
to FIGS. 21-24B can control the multiple antennas depending on
whether the antennas are coplanar (such as in FIGS. 21 and 22) or
are multi-dimensional (such as in FIGS. 23A-24B). Receiver devices
1059 may be charged by haphazard placement of the receiver devices
the enclosure 1050.
[0188] FIG. 29C shows a transmit antenna 1055 on a shelf 1057 of
the enclosure 1050 with receiver devices 1059 to be charged above
and below the shelf 1057. The enclosure 1050 shown in FIG. 29C
includes a door 1058. Thus, when the door 1058 is closed, an
enclosed furnishing detector 290 (FIG. 20) may be used to enhance
power transmission to the receiver devices 1059.
[0189] FIG. 30 illustrates an exemplary embodiment of one or more
antennas (1065 and 1066) disposed in or on a closet 1060. As
non-limiting examples, receiver devices 1069 are illustrated in a
pocket of a coat and in a handbag. In this exemplary embodiment,
the antennas (1065 and 1066) may be originally manufactured as part
of the closet 1060 (i.e., a host furnishing) or the antennas (1065
and 1066) may be disposed in or on the closet 1060 afterwards
(i.e., an existing furniture item). Receiver devices 1069 may be
charged by simply tossing them into the closet 1060 or placing
articles containing the receiver devices 1069 in the closet 1060.
Antenna 1065 is illustrated as within a door frame 1065 of the
closet 1060. Other suitable locations may be on interior walls or
shelves of the closet 1060. Antennas 1066 are illustrated as in or
on the doors of the closet 1060.
[0190] The enclosure 1060 includes doors 1067. Thus, when the doors
1067 are closed, an enclosed furnishing detector 290 (FIG. 20) may
be used to enhance power transmission to the receiver devices 1059.
With multiple antennas (such as transmit or repeater), the
exemplary embodiments discussed above with reference to FIGS.
21-24B can control the multiple antennas depending on whether the
antennas are coplanar (such as in FIGS. 21 and 22) or are
multi-dimensional (such as in FIGS. 23A-24B).
[0191] FIG. 31 illustrates an exemplary embodiment of a transmitter
1075 disposed in or on a bed 1070, In this exemplary embodiment,
the transmitter 1075 may be originally manufactured as part of the
bed 1070 or the transmitter 1075 may be disposed in or on the
closet bed 1070 afterwards (i.e., an existing furniture item).
Receiver devices (not shown) may be charged by placing them on or
under the bed 1070 or placing articles containing the receiver
devices on or under the bed 1070. The transmitter 1075 may be
powered from an AC wall outlet 1078 or other suitable power
source.
[0192] FIG. 32 illustrates an exemplary embodiment of one or more
antennas 1085 disposed in or on a rug 1080, In this exemplary
embodiment, the antennas 1085 may be originally manufactured as
part of the rug 1080 or the antennas 1085 may be disposed in, on,
or under the rug 1080 afterwards (i.e., an existing furniture
item). Receiver devices (not shown) may be charged by placing them
on rug 1080 or placing articles containing the receiver devices on
the rug 1080. The antennas 1085 may be powered from an AC wall
outlet 1078 or other suitable power source.
[0193] FIG. 30 illustrates an exemplary embodiment of one or more
antennas 1085 disposed in or under a rug. In this exemplary
embodiment, the antennas (1065 and 1066) may be originally
manufactured as part of the closet 1060 (i.e., a host furnishing)
or the antennas (1065 and 1066) may be disposed in or on the closet
1060 afterwards (i.e., an existing furniture item). Receiver
devices 1069 may be charged by simply tossing them into the closet
1060 or placing articles containing the receiver devices 1069 in
the closet 1060. Antenna 1065 is illustrated as within a door frame
1065 of the closet 1060. Other suitable locations may be on
interior walls or shelves of the closet 1060. Antennas 1066 are
illustrated as in or on the doors of the closet 1060.
[0194] FIG. 33 illustrates an exemplary embodiment of a
wall-mounted receptacle 1092 on a wall 1090 bearing a transmitter
1095 and for holding one or more receiver devices (not shown). The
wall-mounted receptacle 1092 may include an aligner 1098 to
physically aid the alignment of devices placed within the field of
the wireless charging apparatus. This alignment aid may make the
wall-mounted receptacle 1092 particularly useful for inductive
coupling applications as well as near-field coupling applications.
While not shown, the wall-mounted receptacle 1092 may include
multiple antennas, perhaps in multiple orientations. With multiple
antennas (such as transmit or repeater), the exemplary embodiments
discussed above with reference to FIGS. 21-24B can control the
multiple antennas depending on whether the antennas are coplanar
(such as in FIGS. 21 and 22) or are multi-dimensional (such as in
FIGS. 23A-24B). The receptacle 1092 is illustrated as wall-mounted.
However, other receptacles 1092 with aligners 1098 are contemplated
as within the scope of the present invention, such as, for example,
a desktop receptacle.
[0195] FIG. 34 illustrates an exemplary embodiment of a transmit
antenna 2005 disposed on a wall 2000 and a receiver device 2009
hanging from a receiver device holder 2008 (e.g., a hook) such that
the receiver device 2009 is in a coupling-mode region of the
transmit antenna 2005. This configuration also allows receiver
devices contained within secondary containers such as jeans,
purses, or backpacks to receive charge while the clothing or bags
are hung on the hooks 2008 above the transmit antenna 2005.
[0196] FIG. 35 is a simplified flow chart 2100 illustrating acts
that may be performed in one or more exemplary embodiments of the
present invention. Various exemplary embodiments may include some
or all of the acts illustrated in FIG. 35, as well as other acts
not illustrated. In operation 2102, a wireless charging apparatus
including one or more transmit antennas, one or more repeater
antennas, or a combination thereof may be disposed on or in a host
furnishing or an existing furniture item. In operation 2104, an
electromagnetic field at a resonant frequency of the transmit
antenna may be generated to create a coupling-mode region within a
near field of the transmit antenna. In operation 2106, a receive
device with a receive antenna may be disposed in the coupling-mode
region.
[0197] In operation 2108, the process may check to see if a
receiver is present in the coupling-mode region. If so, in
operation 2110 the wireless charging apparatus may apply power, or
increase power, to the transmit antenna. If not, in operation 2112
the wireless charging apparatus may remove power from, or decrease
power to, the transmit antenna.
[0198] In operation 2114, the process may check to see if the
furniture item is in an enclosed state. If so, in operation 2116
the wireless charging apparatus may increase the power to the
transmit antenna to a level that is compatible with an enclosed
state of the furniture item.
[0199] In operation 2118, the process may check to see if a human
is present in or near the coupling-mode region. If so, in operation
2120 the wireless charging apparatus may adjust the power output of
the transmit antenna to a regulatory level or lower. If not, in
operation 2124 the wireless charging apparatus may adjust the power
output of the transmit antenna above the regulatory level.
[0200] Those of skill in the art would understand that information
and signals may be represented using any of a variety of different
technologies and techniques. For example, data, instructions,
commands, information, signals, bits, symbols, and chips that may
be referenced throughout the above description may be represented
by voltages, currents, electromagnetic waves, magnetic fields or
particles, optical fields or particles, or any combination
thereof.
[0201] Those of skill would further appreciate that the various
illustrative logical blocks, modules, circuits, and algorithm steps
described in connection with the exemplary embodiments disclosed
herein may be implemented as electronic hardware, computer
software, or combinations of both. To clearly illustrate this
interchangeability of hardware and software, various illustrative
components, blocks, modules, circuits, and steps have been
described above generally in terms of their functionality. Whether
such functionality is implemented as hardware or software depends
upon the particular application and design constraints imposed on
the overall system. Skilled artisans may implement the described
functionality in varying ways for each particular application, but
such implementation decisions should not be interpreted as causing
a departure from the scope of the exemplary embodiments of the
invention.
[0202] The various illustrative logical blocks, modules, and
circuits described in connection with the embodiments disclosed
herein may be implemented or performed with a general purpose
processor, a Digital Signal Processor (DSP), an Application
Specific Integrated Circuit (ASIC), a Field Programmable Gate Array
(FPGA) or other programmable logic device, discrete gate or
transistor logic, discrete hardware components, or any combination
thereof designed to perform the functions described herein. A
general purpose processor may be a microprocessor, but in the
alternative, the processor may be any conventional processor,
controller, microcontroller, or state machine. A processor may also
be implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0203] The steps of a method or algorithm described in connection
with the embodiments disclosed herein may be embodied directly in
hardware, in a software module executed by a processor, or in a
combination of the two. A software module may reside in Random
Access Memory (RAM), flash memory, Read Only Memory (ROM),
Electrically Programmable ROM (EPROM), Electrically Erasable
Programmable ROM (EEPROM), registers, hard disk, a removable disk,
a CD-ROM, or any other form of storage medium known in the art. An
exemplary storage medium is coupled to the processor such that the
processor can read information from, and write information to, the
storage medium. In the alternative, the storage medium may be
integral to the processor. The processor and the storage medium may
reside in an ASIC. The ASIC may reside in a user terminal. In the
alternative, the processor and the storage medium may reside as
discrete components in a user terminal.
[0204] In one or more exemplary embodiments, the functions
described may be implemented in hardware, software, firmware, or
any combination thereof. If implemented in software, the functions
may be stored on or transmitted over as one or more instructions or
code on a computer-readable medium. Computer-readable media
includes both computer storage media and communication media
including any medium that facilitates transfer of a computer
program from one place to another. A storage media may be any
available media that can be accessed by a computer. By way of
example, and not limitation, such computer-readable media can
comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage,
magnetic disk storage or other magnetic storage devices, or any
other medium that can be used to carry or store desired program
code in the form of instructions or data structures and that can be
accessed by a computer. Also, any connection is properly termed a
computer-readable medium. For example, if the software is
transmitted from a website, server, or other remote source using a
coaxial cable, fiber optic cable, twisted pair, digital subscriber
line (DSL), or wireless technologies such as infrared, radio, and
microwave, then the coaxial cable, fiber optic cable, twisted pair,
DSL, or wireless technologies such as infrared, radio, and
microwave are included in the definition of medium. Disk and disc,
as used herein, includes compact disc (CD), laser disc, optical
disc, digital versatile disc (DVD), floppy disk and blu-ray disc
where disks usually reproduce data magnetically, while discs
reproduce data optically with lasers. Combinations of the above
should also be included within the scope of computer-readable
media.
[0205] The previous description of the disclosed exemplary
embodiments is provided to enable any person skilled in the art to
make or use the present invention. Various modifications to these
exemplary embodiments will be readily apparent to those skilled in
the art, and the generic principles defined herein may be applied
to other embodiments without departing from the spirit or scope of
the invention. Thus, the present invention is not intended to be
limited to the embodiments shown herein but is to be accorded the
widest scope consistent with the principles and novel features
disclosed herein.
* * * * *