[0001] This disclosure relates generally to wireless power, and more specifically
to a wireless power reception apparatus.
DESCRIPTION OF THE RELATED TECHNOLOGY
[0002] Conventional wireless power systems have been developed with a primary
10 objective of charging a battery in a wireless power reception apparatus, such as a
mobile device, a small electronic device, gadget, or the like. In a conventional wireless
power system, a wireless power transmission apparatus may include a primary coil that
produces an electromagnetic field. The electromagnetic field may induce a voltage in
a secondary coil of a wireless power reception apparatus when the secondary coil is
15 placed in proximity to the primary coil. In this configuration, the electromagnetic field
may transfer power to the secondary coil wirelessly. The power may be transferred
using resonant or non-resonant inductive coupling between the primary coil and the
secondary coil. The wireless power reception apparatus may use the received power
to operate or may store the received energy in a battery for subsequent use.
20
SUMMARY
[0003] The systems, methods, and apparatuses of this disclosure each have several
innovative aspects, no single one of which is solely responsible for the desirable
attributes disclosed herein.
25 [0004] One innovative aspect of the subject matter described in this disclosure can
be implemented in a wireless power reception apparatus. In some implementations,
the wireless power reception apparatus may include a ferrite layer having a void. The
wireless power reception apparatus may also include a first secondary coil configured
3
to generate first power in cooperation with one or more primary coils of a wireless
power transmission apparatus, wherein at least a portion of the first secondary coil
resides in the void of the ferrite layer. The wireless power reception apparatus may
also include one or more second secondary coils configured to generate second power
5 in cooperation with the one or more primary coils of the wireless power transmission
apparatus, where a portion of the second secondary coil is overlaying the portion of the
first secondary coil residing in the void of the ferrite layer.
[0005] Implementations may include one or more of the following features. In the
wireless power reception apparatus, the void of the ferrite layer may extend through an
10 entire thickness of the ferrite layer. In the wireless power reception apparatus, the void
of the ferrite layer may be a recess occupying a portion of a thickness of the ferrite
layer. In the wireless power reception apparatus, the void may be formed by stacking
pieces of ferrite material. In the the wireless power reception apparatus, each of the
first secondary coil and the one or more secondary coils may include a square-shaped
15 or a rectangular-shaped path of copper wire. In the wireless power reception apparatus,
the wireless power reception apparatus may be coupled with an electronic device
wheres the first power and the second power charge a battery of the electronic device.
In the wireless power reception apparatus, the first secondary coil may be a main
secondary coil and the second secondary coils may be auxiliary secondary coils. In the
20 wireless power reception apparatus, the first secondary coil may be an auxiliary
secondary coil and the second secondary coils may be main secondary coils.
[0006] Another innovative aspect of the subject matter described in this disclosure
can be implemented in a wireless power reception apparatus. In some
implementations, the wireless power reception apparatus includes a printed circuit
25 board component. The printed circuit board (PCB) component may include a PCB.
The PCB may include a plurality of layers that include at least a top side of the PCB
and a bottom side of the PCB. The PCB may also include a main secondary coil
including conductive material configured to receive wireless power in the form of
4
electromagnetic energy from one or more primary coils of a wireless power
transmission apparatus, wherein first segments of the main secondary coil reside in a
first plurality of the layers. The PCB can also include an auxiliary secondary coil
including conductive material configured to receive wireless power in the form of
5 electromagnetic energy from the one or more primary coils of the wireless power
transmission apparatus. The first segments of the auxiliary secondary coil may reside
in a second plurality of the layers.
[0007] Implementations may include one or more of the following features. In the
PCB component, the first plurality of the layers may not include the second plurality
10 of the layers. In the PCB component, the first plurality of the layers may include one
or more layers of the second plurality of the layers. In the PCB component, a first layer
of the plurality of layers may include the top side of the PCB and a second layer of the
plurality of layers includes the bottom side of the PCB. In the PCB component, at least
one via connected to the first segments of the main secondary coil. In the PCB
15 component, second segments of the main secondary coil may reside in one or more
layers of the first plurality of the layers, and second segments of the auxiliary secondary
coil may reside in one or more layers of the second plurality of the layers. In the PCB
component, the first and second segments of the main secondary coil do not intersect
with the first and second segments of the auxiliary secondary coil. The PCB
20 component can further include main vias configured to connect the first segments of
the main secondary coil to the second segments of the main secondary coil. The PCB
component can also include auxiliary vias configured to connect the first segments of
the auxiliary secondary coil to the second segments of the auxiliary secondary coil.
[0008] Another innovative aspect of the subject matter described in this disclosure
25 can be implemented in a wireless power reception apparatus. In some
implementations, a method for creating a wireless power receiver apparatus comprising
creating a void in a ferrite material. The method may also include depositing a first
secondary coil on the ferrite material, wherein the first secondary coil is configured to
5
generate first power in cooperation with one or more primary coils of a wireless power
transmission apparatus, wherein at least a portion of the first secondary coil resides in
the void of the ferrite material. The method may also include depositing a second
secondary coil configured on the ferrite material, wherein the second secondary coil is
5 configured to generate second power in cooperation with the one or more primary coils
of the wireless power transmission apparatus, wherein a portion of the second
secondary coil overlays the portion of the first secondary coil residing in the void of
the ferrite material.
[0009] Implementations may include one or more of the following features. In the
10 method, creating the void in the ferrite material may comprise placing pieces of the
ferrite material in a configuration that forms the void. In the method, the pieces of the
ferrite material may be of uniform thickness. In the method, two or more of the pieces
of the ferrite material may be differently shaped. In the method, the ferrite material
may be unitary and wherein creating the void in the ferrite material comprises removing
15 a portion of the unitary ferrite material.
[0010] Details of one or more implementations of the subject matter described in
this disclosure are set forth in the accompanying drawings and the description below.
Other features, aspects, and advantages will become apparent from the description, the
drawings, and the claims. Note that the relative dimensions of the following figures
20 may not be drawn to scale.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 shows an overview of components associated with an example
wireless power system according to some implementations.
25 [0012] Figure 2A is a block diagram illustrating components of a wireless power
receiver apparatus according to some implementations.
6
[0013] Figure 2B is a block diagram illustrating components of a wireless power
receiver apparatus including a main secondary coil and a plurality of auxiliary
secondary coils according to some implementations.
[0014] Figure 3 is a block diagram illustrating a main secondary coil overlapping
5 portions of auxiliary secondary coils in a wireless power receiver apparatus according
to some implementations.
[0015] Figure 4A is a block diagram illustrating a wireless power receiver
apparatus in which secondary coils are recessed into a ferrite material according to
some implementations.
10 [0016] Figure 4B is a block diagram illustrating a wireless power receiver
apparatus in which ferrite material is cut away to accommodate secondary coils
according to some implementations.
[0017] Figure 5A is a block diagram illustrating ferrite material pieces arranged to
create a void configured to accommodate portions of one or more secondary coils
15 according to some implementations.
[0018] Figure 5B is a block diagram illustrating ferrite material pieces arranged to
create a void configured to accommodate portions of one or more secondary coils
according to some implementations.
[0019] Figure 6A illustrates a top view of components of a wireless power receiver
20 apparatus according to some implementations.
[0020] Figure 6B illustrates a bottom view of components of a wireless power
receiver apparatus according to some implementations.
[0021] Figure 7A is a block diagram illustrating coils for use in a wireless power
receiver apparatus including a printed circuit board (PCB) according to some
25 implementations.
[0022] Figure 7B is a block diagram illustrating a bottom view of a PCB including
coils configured for use in a wireless power receiver apparatus according to some
implementations.
7
[0023] Figure 8A is a block diagram illustrating coils configured for use in a
wireless power receiver apparatus including a PCB according to some
implementations.
[0024] Figure 8B is a block diagram illustrating a top view of a PCB including
5 coils configured for use in a wireless power receiver apparatus according to some
implementations.
[0025] Like reference numbers and designations in the various drawings indicate
like elements.
10 DETAILED DESCRIPTION
[0026] The following description is directed to certain implementations for the
purposes of describing innovative aspects of this disclosure. However, a person having
ordinary skill in the art will readily recognize that the teachings herein can be applied
in a multitude of different ways. The described implementations can be implemented
15 in any means, apparatus, system, or method for transmitting or receiving wireless
power.
[0027] A traditional wireless power system may include a wireless power
transmission apparatus and a wireless power reception apparatus. The wireless power
transmission apparatus may include a primary coil that transmits wireless energy (as a
20 wireless power signal) to a corresponding secondary coil in the wireless power
reception apparatus. A primary coil refers to a source of wireless energy (such as
inductive or magnetic resonant energy) in a wireless power transmission apparatus. A
secondary coil is located in a wireless power reception apparatus and receives the
wireless energy. Wireless power transmission is more efficient when the primary and
25 secondary coils are closely positioned. Conversely, the efficiency may decrease (or
the charging may cease) when the primary and secondary coils are misaligned. When
properly aligned, primary coils and secondary coils can transfer wireless energy up to
an amount predetermined by a wireless standard. For example, a wireless power signal
8
may convey 5 Watts (W), 9W, 12W, 15W, or more. The charging capability may be
related to how closely the primary coil and secondary coil are positioned or aligned
with each other. In this disclosure, alignment may refer to a spatial relationship
between a secondary coil of the wireless power reception apparatus and a primary coil
5 of the wireless power transmission apparatus. A misalignment may reduce the
efficiency of the wireless charging or may cause an increase in wireless power signal
from a primary coil to adjust for the misalignment. For example, a primary coil may
output a higher amount of magnetic flux in order to meet the demand of a load
associated with a secondary coil that is not well aligned. Undesirable electromagnetic
10 interference (EMI) may be caused by excess magnetic flux that is not linked to the
secondary coil.
[0028] This disclosure provides systems, methods, and apparatus for wireless
power reception. Various implementations relate generally to a wireless power
reception apparatus that have multiple secondary coils. In accordance with aspects of
15 this disclosure, a wireless power system may utilize one or more primary coils and a
plurality of secondary coils to transfer wireless power from a wireless power
transmission apparatus to a wireless power reception apparatus. For example, a
primary coil may transmit a power signal to a corresponding secondary coil.
[0029] In some implementations, a wireless power reception apparatus includes a
20 ferrite material, a main secondary coil, and one or more auxiliary secondary coils. The
main and auxiliary secondary coils may be arranged where portions of the coils are
stacked on each other. To ensure the stacked coils do not increase an overall thickness
of the wireless power receiver apparatus, the ferrite material may have voids (which
also may be referred to as recesses or cutouts) that make room for overlapping
25 secondary coils. By placing overlapping portions of the secondary coils in the voids,
the overlapping coils do not increase an overall thickness of the wireless power receiver
apparatus.
9
[0030] In some implementations, a wireless power receiver apparatus includes a
printed circuit board (PCB) component including a top layer and bottom layer. On the
top layer, the PCB includes a top-layer main secondary coil including a continuous
concentric path of conductive material. The top layer also includes a top-layer
5 auxiliary secondary coil including noncontinuous paths of conductive material
interspersed with the top-layer main secondary coil. On the bottom layer, the PCB
includes a bottom-layer main secondary coil including a noncontinuous concentric path
of conductive material. The bottom layer also includes a bottom-layer auxiliary
secondary coil including a continuous path of conductive material interspersed with the
10 bottom-layer main secondary coil. The conductive material on a top layer and the
conductive material on the bottom layer may be electrically connected by a vertical
interconnect access (VIA, also referred to as a via for brevity). For example, a via may
include two pads, in corresponding positions on the top layer and the bottom layer, that
are electrically connected by a conductive hole through the PCB. The hole through the
15 PCB may be made to be conductive using electroplating, conductive tube lining, or a
rivet, among other examples. In some implementations, vias are placed at many
portions of the main coil to connect the portions of the bottom-layer non-continuous
concentric paths of the main coil to the continuous concentric paths of the main coil on
the top layer. similarly, several vias connect the portions of the non-continuous top20 layer auxiliary coils to the continuous tracks of the corresponding coil laid on the
bottom layer.
[0031] Particular implementations of the subject matter described in this disclosure
can be implemented to realize one or more of the following potential advantages. In
some implementations, a wireless power receiver apparatus includes overlapping
25 secondary coils placed on a ferrite material. In places where secondary coils overlap,
the wireless power receiver apparatus may be thicker than where secondary coils do
not overlap. Some implementations include voids in the ferrite material to offset an
added thickness arising from overlapping secondary coils. By placing overlapping coil
10
portions in the voids, an overall thickness of the wireless power receiver apparatus is
not increased.
[0032] Figure 1 shows an overview of components associated with an example
wireless power system according to some implementations. The wireless charging
5 system 100 is connected to a power source 104. In Figure 1, the wireless charging
system 100 includes a wireless power transmitter 106 and a wireless power receiver
108. In some implementations, the wireless power transmitter 106 may be
magnetically coupled to the wireless power receiver 108.
[0033] The wireless power transmitter 106 includes a transmitter driver 112
10 coupled to a primary coil 114. In some implementations, the transmitter driver 112
may include a converter. The transmitter driver 112 includes a plurality of switches.
The plurality of switches includes semiconductor switches, such as an insulated gate
bipolar transistor, a metal oxide semiconductor field-effect transistor, a field-effect
transistor, an injection enhanced gate transistor, an integrated gate commutated
15 thyristor, a gallium nitride based switch, a silicon carbide based switch, a gallium
arsenide based switch, diodes, or the like. In some implementations, the primary coil
114 may be a wound copper wire.
[0034] Further, the wireless power receiver 108 includes secondary coils 116 and
a receiver driver 118. In some implementations, the secondary coils 116 includes a
20 main secondary coil 120 and one or more auxiliary secondary coils 122.
[0035] The wireless power receiver 108 may form a part of a two-coil wireless
charging system, a three-coil wireless charging system, and a four-coil wireless
charging system. As will be appreciated, the two-coil wireless charging system
includes only the receiver and the transmitter. A three-coil charging system may
25 include a field focusing coil in addition to the receiver and the transmitter. A four-coil
charging system may include a phase compensation coil in addition to the receiver, the
field focusing coil, and the transmitter.
11
[0036] In some implementations, the main secondary coil 120 and the plurality of
auxiliary secondary coils 122 are resonant coils. In particular, each of the main
secondary coil 120 and the plurality of auxiliary secondary coils 122 may be coupled
to a corresponding capacitor. In one specific embodiment, the main secondary coil 120
5 and the plurality of auxiliary secondary coils 122 are compatible with a Wireless Power
Consortium (WPC) standard (Qi) that is defined in a frequency range of 100 kHz to
200 kHz.
[0037] In Figure 1, the receiver driver 118 includes a main converter 126 and
auxiliary converter 124. The main secondary coil 120 is coupled to the main converter
10 126. The main converter 126 includes a main output terminal and is configured to
rectify a voltage induced at the main secondary coil 120 during operation.
[0038] The auxiliary secondary coils 122 are coupled to the auxiliary converter
124. The auxiliary converter 124 is configured to rectify a voltage induced at the
auxiliary secondary coils 122 during operation. In some implementations, each
15 auxiliary secondary coil 122 is coupled to a corresponding auxiliary converter 124. In
some implementations, at least one of the auxiliary converters is a passive rectifier. In
one specific implementation, the passive rectifier is a diode rectifier.
[0039] In some implementations, the auxiliary converter 124 are coupled to each
other to form an auxiliary output terminal. In accordance with aspects of the present
20 specification, the main output terminal of the main converter 126 is coupled to the
auxiliary output terminal in series. Further, a load is coupled across the main output
terminal and the auxiliary output terminal.
[0040] In some implementations, conventional wireless charging systems may
include a single secondary coil. This secondary coil contributes towards the supply of
25 a voltage to a load, such as a battery. In one scenario, if the secondary coil is not
aligned with a primary coil, in order to induce a desired voltage in the secondary coil,
the current in the primary coil has to be higher than that current in the primary coil
when the secondary coil is aligned with the primary coil. As a result, the efficiency of
12
the conventional wireless charging system is compromised. Shortcomings of the
conventional wireless charging systems can be circumvented using implementations of
the wireless charging system 100.
[0041] As noted hereinabove, the wireless power receiver 108 includes the
5 auxiliary secondary coils 122 in addition to the main secondary coil 120. The
combination of the main secondary coil 120 and the auxiliary secondary coils 122 is
configured to provide desired voltage to the load, via the corresponding main and
auxiliary converters 124, 126, even in an event of misalignment of the main secondary
coil 120 with respect to the primary coil 114.
10 [0042] In particular, during operation of the wireless charging system 100, power
provided from the power source 104 is converted to alternating current (AC) form by
the transmitter driver 112 and provided to the primary coil 114. Accordingly, the
primary coil 114 is energized, and a magnetic field is generated at the primary coil 114.
The magnetic field at the primary coil 114 induces a voltage at the main secondary coil
15 120 and one or more auxiliary secondary coils 122 based on an alignment of the main
secondary coil 120 and the auxiliary secondary coils 122 with respect to the primary
coil 114.
[0043] The voltage induced at the main secondary coil 120 and the auxiliary
secondary coils 122 is transmitted to the main converter 126 and the auxiliary converter
20 124, respectively. A rectified voltage is generated at the main output terminal of the
main converter 126, and a rectified voltage is generated at the auxiliary output terminal
of the auxiliary converter 124. The communication subunit 128 and controller 132 can
cooperate to exchange power information between components of the wireless
charging system 100.
25 [0044] In some implementations, if a central axis of the primary coil 114 is aligned
with a central axis of the main secondary coil 120, the main secondary coil 120 is
aligned with the primary coil 114. When the main secondary coil 120 is aligned with
the primary coil 114, the main secondary coil 120 has satisfactory magnetic coupling
13
with the primary coil 114. In the event of satisfactory magnetic coupling between the
primary coil 114 and the main secondary coil 120, a higher voltage is induced across
the main secondary coil 120 compared to a voltage induced at the main secondary coil
120 during a misaligned condition of the main secondary coil 120 with respect to the
5 primary coil 114.
[0045] In some implementations, the main converter 126 and the auxiliary
converter 124 are connected in series. Sometimes during power transfer, the primary
coil 114 is aligned with the main secondary coil 120. During alignment, any voltage
induced by the main secondary coil 120 will be relatively high whereas voltages in the
10 one or more auxiliary secondary coils 122 will be relatively low. Hence, during
alignment, there will be relatively high rectified voltages in the main converter 126 and
relatively low rectified voltages in the auxiliary converter 124. During alignment, the
resulting power contribution from the main secondary coil 120 will be higher than
power contribution from the one or more auxiliary secondary coils 122. As the primary
15 coil 114 moves out of alignment with the main secondary coil 120, voltage induced in
the mail secondary coil 120 drops. For any auxiliary secondary coil 122 that moves
into more favorable alignment with the primary coil 114, induced voltage increases.
When an auxiliary secondary coil is more favorably aligned with the primary coil 114,
rectified voltages in the auxiliary converter 124 increase whereas rectified voltages in
20 the main converter 126 decrease. Despite misalignment between the primary coil 114
and main secondary coil 120, load voltage and power are maintained by power
contributions of the auxiliary secondary coils(s).
[0046] Figure 2A is a block diagram illustrating components of a wireless power
receiver apparatus according to some implementations. In Figure 2B, a wireless power
25 receiver apparatus includes a ferrite material 202 and a secondary coil 204. The ferrite
material 202 may reside between the secondary coil 204 and the electronic components
of the electronic device. Hence, the ferrite material 202 may shield those electronic
14
components from magnetic fields and help focus the electromagnetic energy onto the
secondary coil 204.
[0047] Figure 2B is a block diagram illustrating components of a wireless power
receiver apparatus including a main secondary coil and a plurality of auxiliary
5 secondary coils according to some implementations. Although the wireless power
receiver apparatus shown in Figure 2A includes a single secondary coil, some
implementations include multiple secondary coils. In some instances, a wireless power
receiver apparatus includes a main secondary coil and one or more auxiliary secondary
coils. The main and auxiliary secondary coils can be placed in any suitable
10 arrangement. For example, portions of the auxiliary secondary coils may overlay
portions of a main secondary coil. In Figure 2B, the wireless power receiver apparatus
includes a ferrite material 206 and a main secondary coil 208 (broken line). Auxiliary
secondary coils 210 are superimposed (which also may be referred to as “overlayed”
or “overlapped”) over portions of the main secondary coil 208. Portions of the main
15 secondary coil 208 and the auxiliary secondary coils 210 overlap. When portions of
auxiliary secondary coils overlap with a main secondary coil, an overall thickness of a
wireless power receiver apparatus may increase. Increasing the thickness of the
wireless power receiver apparatus may result in the apparatus that is too large for
certain environments. Some implementations avoid increasing thickness by recessing
20 portions of the secondary coils into voids of a ferrite material. The following
discussion will provide additional details about these and other implementations.
[0048] Figure 3 is a block diagram illustrating a main secondary coil overlapping
portions of auxiliary secondary coils in a wireless power receiver apparatus according
to some implementations. In Figure 3, a wireless power receiver apparatus includes a
25 ferrite material 302, main secondary coil 304, and auxiliary secondary coils 306. In
Figure 3, the auxiliary secondary coils 306 are superimposed over the main secondary
coil 304. In some implementations, the secondary coils (304 and 306) and ferrite
material 302 form three layers. The ferrite material 302 forms a base layer on top of
15
which resides the main secondary coil 304. The auxiliary secondary coils 306 may be
stacked atop the main secondary coil 304. Overlapping regions 308 identify portions
of the auxiliary secondary coils 306 that overlap portions of the main secondary coil
304.
5 [0049] In some implementations, at least a portion of the main secondary coil 304
is recessed into the ferrite material 302. For example, portions of the main secondary
coil 304 that overlap auxiliary secondary coils 306 may be recessed into the ferrite
material. Recessing one or more portions of the main secondary coil 304 into the ferrite
material 302 can reduce the thickness of the wireless power receiver apparatus. The
10 discussion of Figures 4A-4B describes how some implementations may recess
secondary coils into a ferrite material.
[0050] Figure 4A is a block diagram illustrating a wireless power receiver
apparatus in which secondary coils are recessed into a ferrite material according to
some implementations. Figure 4A shows a wireless power receiver apparatus
15 including a ferrite material 402, main secondary coil 404, and auxiliary secondary coils
406. In Figure 4A, the auxiliary secondary coils 406 are superimposed over the main
secondary coil 404. Figure 4A includes a cross-sectional view 407 in which the main
secondary coil 404 is fully recessed into the ferrite material 402. As shown, the
auxiliary secondary coils 406 are stacked on the main secondary coil 404 and ferrite
20 material 402. In Figure 4A, a layer of the ferrite material 402 underlies the main
secondary coil 404. However, in some implementations, the ferrite material 402 is
completely cut away so no ferrite material underlies at least one portion of at least one
secondary coil. Such an example will be described below (see Figure 4B). Figure 4A
also presents a cross-sectional view 409 showing portions of the main secondary coil
25 404 and the auxiliary secondary coils 406. The cross-sectional view 409 illustrates
non-overlapping portions of the main and auxiliary secondary coils (404 and 406) that
are not recessed into the ferrite material 402.
16
[0051] Figure 4B is a block diagram illustrating a wireless power receiver
apparatus in which ferrite material is cut away to accommodate secondary coils
according to some implementations. Figure 4B shows a wireless power receiver
apparatus including a ferrite material 402, main secondary coil 404, and auxiliary
5 secondary coils 406. In Figure 4B, the auxiliary secondary coils 406 are superimposed
over the main secondary coil 404. Figure 4B includes a cross-sectional view 411 in
which the ferrite material 402 is completely removed to accommodate portions of the
main secondary coil 404. In the cross-sectional view 411, the ferrite material 402 does
not underlie the portions of the main secondary coil 404.
10 [0052] Figures 4A-4B show how the ferrite material may include voids in which
portions of the secondary coils reside. The voids may be recesses in the thickness of
the ferrite material (see view 407) or sections where the ferrite material is cutout
altogether (see view 411). One or more recesses or cutouts may be formed by arranging
ferrite material of varying thickness and shape.
15 [0053] Figure 5A is a block diagram illustrating ferrite material pieces arranged to
create a void configured to accommodate portions of one or more secondary coils
according to some implementations. In Figure 5A, three pieces of ferrite material are
placed in juxtaposition. That is, ferrite material piece 504 is placed next to ferrite
material piece 506 which is next to ferrite material piece 508. As arranged, the ferrite
20 material pieces create a void 502. In Figure 5A, the void 502 forms a recess in the
ferrite material pieces. In some implementations, at least a portion of a secondary coil
is placed in the void 502. For example, overlapping portions of a main secondary coil
and an auxiliary secondary coil may reside in the void 502. In this example, all portions
of secondary coils reside atop the ferrite material pieces 504, 506, 508, and will
25 therefore reside atop an underlying ferrite material. Implementations may form voids
by arranging (such as by stacking and juxtaposing) ferrite material pieces in any
suitable configuration. The ferrite material pieces can be of any suitable thickness and
shape.
17
[0054] Figure 5B is a block diagram illustrating ferrite material pieces arranged to
create a void configured to accommodate portions of one or more secondary coils
according to some implementations. In Figure 5B, a ferrite material piece 510 in
proximity to, but not in contact with, a ferrite material piece 512. In this arrangement,
5 the ferrite material pieces 510, 512 create a void 514. In Figure 5B, the void 514 forms
a cutout configured to accommodate one or more portions of one or more secondary
coils. For example, overlapping portions of a main secondary coil and an auxiliary
secondary coil may reside in the void 514. In this example, overlapping portions of
secondary coils reside between ferrite material pieces 510, 512 and will not reside on
10 any underlying ferrite material.
[0055] One or more recesses or cutouts may be formed by milling or otherwise
removing ferrite material. The ferrite material may be one unitary piece or a composite
of multiple ferrite material pieces. Figures 6A-B show additional implementations
where the voids are cutouts of the ferrite material.
15 [0056] Figure 6A illustrates a top view of components of a wireless power receiver
apparatus according to some implementations. In Figure 6A, the wireless power
receiver apparatus includes a ferrite material 602, main secondary coil 604, and
auxiliary secondary coils 606. The main secondary coil 604 and auxiliary secondary
coils 606 can include a Litz wire or other suitable conductive material(s) wound in any
20 suitable geometric forms, such as square-shaped forms shown in Figure 6A. The Litz
wire or other suitable conductive material(s) may be wound in any suitable direction to
form the secondary coils 604 and 606. In some implementations, the wire is wound
clockwise or counterclockwise to form the square-shape in Figure 6A. As described
above, one or more portions of one or more secondary coils may be recessed in the
25 ferrite material 602. Figure 6B shows how portions of the auxiliary secondary coils
606 may be recessed into the ferrite material 602.
[0057] Figure 6B illustrates a bottom view of components of a wireless power
receiver apparatus according to some implementations. In Figure 6B, the wireless
18
power receiver apparatus includes a ferrite material 602, and auxiliary secondary coils
606. As shown, portions of the ferrite material 602 are cut away to accommodate
portions of the auxiliary secondary coils 606. Although not shown in Figure 6B,
portions of the auxiliary secondary coil that are recessed in the ferrite material 602 are
5 overlaid by portions of the main secondary coil 604.
[0058] In some implementations, any suitable portion of a secondary coil may be
recessed into one or more voids in the ferrite material. In some instances, the ferrite
material is a unitary piece of ferrite material, where portions have recesses to
accommodate secondary coils. In some instances, the ferrite material may be absent
10 such that the ferrite material is not contiguous (see Figure 6B).
[0059] Figure 7A is a block diagram illustrating coils configured for use in a
wireless power receiver apparatus including a PCB according to some
implementations. Figure 7A shows a bottom-layer main secondary coil 702 and a
bottom-layer auxiliary secondary coil 704. Although shown separately in Figure 7A,
15 the bottom-layer main secondary coil 702 and bottom-layer auxiliary secondary coil
704 are configured for cooperative placement on a PCB (see Figure 7B).
[0060] Figure 7B is a block diagram illustrating a bottom view of a PCB including
coils configured for use in a wireless power receiver apparatus according to some
implementations. In Figure 7B, a PCB 706 includes the bottom-layer main secondary
20 coil 702 and the bottom-layer auxiliary secondary coil 704. The main and auxiliary
secondary coils reside on a bottom layer of the PCB 706. The bottom-layer main
secondary coil 702 is not a continuous path of conductive material. Rather, the bottomlayer main secondary coil 702 includes concentric conductive paths and noncontinuous conductive paths (see Figure 7A for an isolated view of conductive paths
25 included in the main secondary coil 702). The bottom-layer auxiliary secondary coil
704 is interspersed among paths of the bottom-layer main secondary coil 702. The
bottom-layer auxiliary secondary coil 704 includes a continuous, concentric path of
conductive material and a straight path of conductive material representing the end
19
connection of the coil (see Figure 7A for an isolated view of the paths). In some
implementations, the PCB can include multiple bottom-layer auxiliary secondary coils.
[0061] The PCB 706 includes multiple main vias 708 that travel through PCB
layers to connect the bottom-layer main secondary coil 702 to a top-layer main
5 secondary coil (not shown in Figure 7B; see Figures 8A-B). The bottom-layer auxiliary
secondary coil 704 includes auxiliary vias 710 that travel through PCB layers to
connect the bottom-layer auxiliary secondary coil 704 to a top-layer auxiliary
secondary coil (not shown in Figure 7B; see Figures 8A-B). The main and auxiliary
vias interconnect the top and bottom layers of the coils and in turn, increase the
10 effective thickness of the coils. This reduces the electrical resistance, thereby reducing
power loss.
[0062] Figure 8A is a block diagram illustrating coils configured for use in a
wireless power receiver apparatus including a PCB according to some
implementations. Figure 8A shows a top-layer main secondary coil 802 and a top-layer
15 auxiliary secondary coil 804. Although shown separately in Figure 8A, the top-layer
main secondary coil 802 and top -layer auxiliary secondary coil 804 are configured for
cooperative placement on a PCB (see Figure 8B).
[0063] Figure 8B is a block diagram illustrating a top view of a PCB including
coils configured for use in a wireless power receiver apparatus according to some
20 implementations. In Figure 8B, a PCB 806 includes the top-layer main secondary coil
802 and the top-layer auxiliary secondary coil 804. The main and auxiliary secondary
coils reside in a top layer of the PCB 806. The top-layer main secondary coil 802
includes a continuous path of conductive material and a small path of conductive
material representing the end connection. The top-layer auxiliary secondary coil 804
25 resides among the continuous path of the top-layer main secondary coil 802. The toplayer auxiliary secondary coil 804 includes non-continuous paths of conductive
material (see Figure 7A for an isolated view of the paths). The main vias 808 travel
through PCB layers to connect the top-layer main secondary coil 802 to the bottom-
20
layer main secondary coil 702. Auxiliary vias 810 that travel through PCB layers
connect the top-layer auxiliary secondary coil 804 to the bottom-layer auxiliary
secondary coil 704. The main and auxiliary vias connect the top and bottom layers of
the main coil and those of the auxiliary coil in turn increase thickness of the main and
5 the auxiliary coils. as a result, the electrical resistance of these coils is reduced and in
turn the conduction power loss is reduced. In some implementations, the PCB can
include more than one top-layer auxiliary secondary coils. Also, in other
implementations, the main coil and the auxiliary coils can be disposed in multiple
layers of the PCB such that they do not get shorted. In addition, using multiple vias
10 connecting the multiple layers either completely or partially (hidden vias) the overall
thickness of the main coils and the auxiliary coils are increased to reduce the overall
losses.
[0064] Some implementations may not include both top-layer and bottom-layer
coils. Some implementations may include main and secondary coils residing in a
15 plurality of layers. Referring to Figure 7B, in some implementations, segments of the
main secondary coil 702 can reside in a plurality of layers of the PCB 706. For
example, the via 708 may be connected to a plurality of segments of the main secondary
coil 702, where each segment resides in a different layer of the PCB 706. In some
instances, the segments are superimposed in different layers of the PCB. The auxiliary
20 secondary coil 704 may be similarly segmented and disposed in a plurality of layers.
In some implementations, the plurality of layers includes at least one of the top and
bottom sides of the PCB. In some implementations, segments of the main secondary
coil do not intersect with segments of the auxiliary secondary coil.
[0065] Figures 1–8B and the operations described herein are examples meant to
25 aid in understanding example implementations and should not be used to limit the
potential implementations or limit the scope of the claims. Some implementations may
perform additional operations, fewer operations, operations in parallel or in a different
order, and some operations differently.
21
[0066] As used herein, a phrase referring to “at least one of” or “one or more of” a
list of items refers to any combination of those items, including single members. For
example, “at least one of: a, b, or c” is intended to cover the possibilities of: a only, b
only, c only, a combination of a and b, a combination of a and c, a combination of b
5 and c, and a combination of a and b and c.
[0067] Various modifications to the implementations described in this disclosure
may be readily apparent to persons having ordinary skill in the art, and the generic
principles defined herein may be applied to other implementations without departing
from the scope of this disclosure. Thus, the claims are not intended to be limited to the
10 implementations shown herein but are to be accorded the widest scope consistent with
this disclosure, the principles and the novel features disclosed herein.
[0068] Additionally, various features that are described in this specification in the
context of separate implementations also can be implemented in combination in a
single implementation. Conversely, various features that are described in the context
15 of a single implementation also can be implemented in multiple implementations
separately or in any suitable subcombination. As such, although features may be
described above as acting in particular combinations, and even initially claimed as
such, one or more features from a claimed combination can in some cases be excised
from the combination, and the claimed combination may be directed to a
20 subcombination or variation of a subcombination.
[0069] Similarly, while operations are depicted in the drawings in a particular
order, this should not be understood as requiring that such operations be performed in
the particular order shown or in sequential order, or that all illustrated operations be
performed, to achieve desirable results. Further, the drawings may schematically
25 depict one or more example processes in the form of a flowchart or flow diagram.
However, other operations that are not depicted can be incorporated in the example
processes that are schematically illustrated. For example, one or more additional
operations can be performed before, after, simultaneously, or between any of the
22
illustrated operations. In some circumstances, multitasking and parallel processing
may be advantageous. Moreover, the separation of various system components in the
implementations described above should not be understood as requiring such
separation in all implementations, and it should be understood that the described
5 program components and systems can generally be integrated together in a single
software product or packaged into multiple software products.

We Claim:

1. A wireless power reception apparatus comprising:
a ferrite layer including a void;
5 a first secondary coil configured to generate first power in cooperation with one
or more primary coils of a wireless power transmission apparatus,
wherein at least a portion of the first secondary coil resides in the void
of the ferrite layer; and
a one or more second secondary coils configured to generate second power in
10 cooperation with the one or more primary coils of the wireless power
transmission apparatus, a portion of the second secondary coil
overlaying the portion of the first secondary coil residing in the void of
the ferrite layer.
2. The wireless power reception apparatus of claim 1, wherein the void of the
15 ferrite layer extends through an entire thickness of the ferrite layer.
3. The wireless power reception apparatus of claim 1, wherein the void of the
ferrite layer is a recess occupying a portion of a thickness of the ferrite layer.
4. The wireless power reception apparatus of claim 1, wherein the void is formed
by stacking pieces of ferrite material.
20 5. The wireless power reception apparatus of claim 1, wherein each of the first
secondary coil and the one or more secondary coils includes a square-shaped or a
rectangular-shaped path of copper wire.
6. The wireless power reception apparatus of claim 1, wherein the wireless power
reception apparatus is coupled with an electronic device, and wherein the first power
25 and the second power charge a battery of the electronic device.
24
7. The wireless power reception apparatus of claim 1, wherein the first secondary
coil is a main secondary coil and wherein the second secondary coils are an auxiliary
secondary coil.
8. The wireless power reception apparatus of claim 1, wherein the first secondary
5 coil is an auxiliary secondary coil and wherein the second secondary coils are main
secondary coils.
9. A printed circuit board component of a wireless power reception apparatus
comprising:
a printed circuit board (PCB) including a plurality of layers that include at least
10 a top side of the PCB and a bottom side of the PCB;
a main secondary coil including conductive material configured to receive
wireless power in the form of electromagnetic energy from one or more
primary coils of a wireless power transmission apparatus, wherein first
segments of the main secondary coil reside in a first plurality of the
15 layers; and
an auxiliary secondary coil including conductive material configured to receive
wireless power in the form of electromagnetic energy from the one or
more primary coils of the wireless power transmission apparatus,
wherein first segments of the auxiliary secondary coil reside in a second
20 plurality of the layers.
10. The printed circuit board component of claim 9, wherein the first plurality of
the layers does not include the second plurality of the layers.
11. The printed circuit board component of claim 9, wherein the first plurality of
the layers includes one or more layers of the second plurality of the layers.
25
12. The printed circuit board component of claim 9, wherein a first layer of the
plurality of layers includes the top side of the PCB and a second layer of the plurality
of layers includes the bottom side of the PCB.
13. The printed circuit board component of claim 9, further comprising at least one
5 via connected to the first segments of the main secondary coil.
14. The printed circuit board component of claim 9, wherein second segments of
the main secondary coil reside in one or more layers of the first plurality of the layers,
and wherein second segments of the auxiliary secondary coil reside in one or more
layers of the second plurality of the layers.
10 15. The printed circuit board component of claim 14, wherein the first and second
segments of the main secondary coil do not intersect with the first and second segments
of the auxiliary secondary coil.
16. The printed circuit board component of claim 14, further including:
main vias configured to connect the first segments of the main secondary coil
15 to the second segments of the main secondary coil; and
auxiliary vias configured to connect the first segments of the auxiliary
secondary coil to the second segments of the auxiliary secondary coil.
17. A method for creating a wireless power receiver apparatus comprising:
creating a void in a ferrite material;
20 depositing a first secondary coil on the ferrite material, wherein the first
secondary coil is configured to generate first power in cooperation with
one or more primary coils of a wireless power transmission apparatus,
wherein at least a portion of the first secondary coil resides in the void
of the ferrite material; and
25 depositing a second secondary coil configured on the ferrite material, wherein
the second secondary coil is configured to generate second power in
cooperation with the one or more primary coils of the wireless power
26
transmission apparatus, wherein a portion of the second secondary coil
overlays the portion of the first secondary coil residing in the void of
the ferrite material.
18. The method of claim 17, wherein creating the void in the ferrite material
5 comprises placing pieces of the ferrite material in a configuration that forms the void.
19. The method of claim 17, wherein the pieces of the ferrite material are of
uniform thickness.
20. The method of claim 17, wherein two or more of the pieces of the ferrite
material are differently shaped.
10 21. The method of claim 17, wherein the ferrite material is unitary and wherein
creating the void in the ferrite material comprises removing a portion of the unitary
ferrite material.