[0001] The present invention relates to wireless power, and more specifically,
to a wireless power transmission apparatus.
5 BACKGROUND OF THE INVENTION
[0002] Conventional wireless power systems have been developed with a
primary 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
10 include a primary coil that produces an electromagnetic field and a charging
surface on which wireless power reception apparatuses are placed. The
electromagnetic field may induce a voltage in a secondary coil of the wireless
power reception apparatus when the secondary coil is placed in proximity to the
primary coil. In some instances, the voltage is induced when the wireless power
15 reception apparatus is placed on the charging surface of the wireless power
transmission apparatus. In this configuration, the electromagnetic field may
wirelessly transfer power to the secondary coil. The power may be transferred
using resonant or non-resonant inductive coupling between the primary coil and
the secondary coil. In some instances, the power also may be transferred
20 continuously without interruption. As the wireless power transmission apparatus
continuously transmits power to the wireless power reception apparatus,
temperature of charging surface, transmission coil, reception coil or their
associated electronics may rise beyond acceptable limits.
25 BRIEF SUMMARY OF THE INVENTION
[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.
[0004] One innovative aspect of the subject matter described in this disclosure
30 can be implemented in a wireless power transmission apparatus. In some
3
implementations, the wireless power transmission apparatus may include a first
primary coil of a plurality of primary coils configured to transmit a first wireless
power to a first wireless power reception apparatus. The wireless power
transmission apparatus also may include a power control unit configured to detect
5 the first wireless power reception apparatus in proximity to the first primary coil
of the wireless power transmission apparatus, and determine first time slices
during which to power the first primary coil to cause the first primary coil to
transmit the first wireless power to the first wireless power reception apparatus.
[0005] In some implementations, the power control unit may be further
10 configured to determine second time slices during which to cease transmission of
the first wireless power to the first wireless power reception apparatus, wherein
the first time slices are interspersed with the second time slices, and cause the first
primary coil to cease transmission of the first wireless power to the first wireless
power reception apparatus during the second time slices.
15 [0006] In some implementations, a battery may be associated with the first
wireless power reception apparatus, wherein the battery is configured to charge up
to a first percentage of battery capacity in a first time period, where the first time
period is substantially similar to a second time period for continuously charging
the battery up to the charge percentage.
20 [0007] In some implementations, the cessation of transmission of the first
wireless power may keep a temperature below a thermal limit in one or more of
an interface surface, a transmitter coil, a receiver coil, and electronics in the
wireless power transmission apparatus.
[0008] In some implementations, the power control unit may be further
25 configured to determine, during one or more of the first time slices, that a thermal
limit has been exceeded, and cease, in response to the determination that thermal
limit has been exceeded, provision of the first wireless power to the first wireless
power reception apparatus during the one or more of the first time slices.
[0009] In some implementations, the thermal limit may indicate a maximum
30 temperature of an interface surface of the wireless power transmission apparatus.
4
[0010] In some implementations, the wireless power reception apparatus may
be associated with a device rating, and where a duration of the first time slices is
based, at least in part, on the device rating.
[0011] In some implementations, the power control unit may be further
5 configured to detect a second wireless power reception apparatus in proximity to a
second primary coil of the plurality of primary coils, and determine second time
slices during which to power the second primary coil to cause the second primary
coil to transmit a second wireless power to the second wireless power reception
apparatus, wherein the second time slices are interspersed with the first time
10 slices. The second primary coil may be configured to transmit the second wireless
power to the second wireless power reception apparatus.
[0012] In some implementations, the power control unit may be further
configured to determine that a battery charge threshold associated with the second
wireless power reception apparatus has been exceeded, and cause the second
15 primary coil to cease transmission of the second wireless power during one or
more of the second time slices in response to the determination that the battery
charge threshold has been exceeded. The second primary coil may be further
configured to cease transmission of the second wireless power to the second
wireless power reception apparatus in response to the determination that the
20 battery charge threshold has been exceeded.
[0013] In some implementations, each of the first time slices has a first
duration and each of the second time slices may have a second duration, and the
power control unit may be further configured to determine a charge state of a
battery associated with the second wireless power reception apparatus, increase
25 the first duration based on the charge state, and decrease the second duration
based on the charge state.
[0014] In some implementations, each of the first time slices is of a first
duration and each of the second time slices is of a second duration, and the power
control unit may be further configured to determine a user-configurable charging
30 priority associated with the second wireless power reception apparatus, and
modify the first duration based on the user-configurable charging priority.
5
[0015] In some implementations, the wireless power transmission apparatus
also may include a first user interface (UI) configured to present indicia indicating
charging status of at least one of the first primary coil and the second primary coil.
[0016] In some implementations, the wireless power transmission apparatus
5 also may include another power control unit configured to detect a second
wireless power reception apparatus in proximity to a second primary coil of the
plurality of primary coils, determine second time slices during which to power the
second primary coil to cause the second primary coil to transmit a second wireless
power to the second wireless power reception apparatus, and provide the second
10 wireless power to the second primary coil during the second time slices. The
second primary coil may be configured to transmit the second wireless power to
the second wireless power reception apparatus.
[0017] In some implementations, the second time slices are interspersed with
the first time slices.
15 [0018] In some implementations, the wireless power transmission apparatus
may include another power control unit configured to power the first primary coil
during the first time slices, where the first wireless power is based on power from
each of the power control units
[0019] Another innovative aspect of the subject matter described in this
20 disclosure can be implemented as a method. The method may include operations
for performing any features of the above-mentioned wireless power transmission
apparatuses.
[0020] Another innovative aspect of the subject matter described in this
disclosure can be implemented as a computer-readable medium having stored
25 therein instructions which, when executed by a processor, causes the processor to
perform operations for performing any features of the above-mentioned wireless
power transmission apparatuses.
[0021] Another innovative aspect of the subject matter described in this
disclosure can be implemented as a system having means for implementing any
30 operations for performing any features of the above-mentioned wireless power
transmission apparatuses.
6
[0022] 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
5 following figures may not be drawn to scale.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 shows an example wireless power system that includes a
wireless power transmission apparatus capable of charging multiple wireless
10 power reception apparatuses.
[0024] Figure 2 shows an example wireless power transmission apparatus
having multiple layers of primary coils arranged in an overlapping pattern.
[0025] Figure 3 is a block diagram illustrating an example wireless power
transmission apparatus.
15 [0026] Figure 4A is an example graphical representation of intermittent
wireless power transfer from a wireless power transmission apparatus to a
wireless power reception apparatus.
[0027] Figure 4B is an example graphical representation of charging status
resulting from intermittent wireless power transfer between a wireless power
20 transmission apparatus and a wireless power reception apparatus.
[0028] Figure 5A is an example graphical representation of power-related
time slicing associated with charging a single wireless power reception apparatus.
[0029] Figure 5B is an example graphical representation of power-related
time slicing associated with charging two wireless power reception apparatuses.
25 [0030] Figure 5C is an example graphical representation of dynamically
updating a schedule of time slices upon detection of an additional wireless power
apparatus.
[0031] Figure 6 is a block diagram illustrating a wireless power transmission
apparatus in which a power control unit can independently control different
30 transmitter circuits.
7
[0032] Figure 7 is a block diagram illustrating a wireless power transmission
apparatus in which multiple power control units can cooperatively provide power
to a transmitter circuit.
[0033] Figure 8 is a flow diagram illustrating example operations of a process
5 for providing wireless power to a wireless power reception apparatus
[0034] Like reference numbers and designations in the various drawings
indicate like elements.
DETAILED DESCRIPTION OF THE INVENTION
10 [0035] 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 in any means, apparatus, system or method
15 for transmitting or receiving wireless power.
[0036] A conventional wireless power system may include a wireless power
transmission apparatus and one or more wireless power reception apparatuses.
The wireless power transmission apparatus may include one or more primary coils
that transmits wireless energy to one or more corresponding secondary coils in the
20 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 in the wireless power reception
apparatus receives the wireless energy.
[0037] Wireless power transmission may be more efficient when the primary
25 and secondary coils are closely positioned. Conversely, the efficiency may
decrease when the primary and secondary coils are misaligned. Inefficiencies in
wireless power transfer may cause temperatures to increase on a charging surface
of the wireless power transmission apparatus or in various components of the
wireless power system. This problem may be compounded when multiple devices
30 are placed on a charging pad. In some instances, even with relatively efficient
transfer of wireless power, components in the wireless power system may exhibit
8
relatively high temperatures. As temperatures rise, heat may build-up beyond
critical limits, causing system failure.
[0038] Some wireless power reception apparatuses may be associated with
different preferences, priorities, and requirements. For example, a user may want
5 to quickly charge devices of a first type at a relatively high power level and
slowly charge devices of a second type at lower power levels. Similarly, when
charging multiple devices, the user may want to assign higher priority to certain
devices and lower priority to others. For example, the user may assign highest
priority to a first mobile phone and lower priorities to other mobile phones, where
10 higher priority devices receive more wireless power than lower priority devices.
[0039] Various implementations of this disclosure relate generally to
intermittent wireless charging in a wireless power transmission apparatus. Some
implementations more specifically relate to a wireless power transmission
apparatus (such as a charging pad or surface) that intermittently provides wireless
15 power to one or more wireless power reception apparatuses to enable the wireless
power reception apparatuses to cool during time slices in which wireless power is
not transferred. In this disclosure, a time slice is a time period of a particular
duration. Some implementations also may relate to a wireless power transmission
apparatus that intermittently provides wireless power to support various charging
20 profiles for different wireless power reception apparatuses. In accordance with
this disclosure, a wireless power transmission apparatus may include a power
control unit that may detect a wireless power reception apparatus in proximity to a
primary coil. The power control unit may determine first time slices during which
wireless power will be provided to the wireless power reception apparatus. The
25 power control unit also may determine second time slices during which wireless
power will not be provided to the wireless power reception apparatus, where the
second time slices are interspersed with the first time slices. During the second
time slices (no power provided), thermal loads that accumulated during the first
time slices (wireless power provided) may dissipate.
30 [0040] In some implementations, the power control unit may detect multiple
wireless power reception apparatuses. The power control unit also may determine
9
different time slices for each of the multiple wireless power reception apparatuses.
For example, the power control unit may detect a first wireless power reception
apparatus and a second wireless power reception apparatus. The power control
unit may determine first time slices for the first wireless power reception
5 apparatus and second time slices for the second wireless power reception
apparatus, where the first time slices are of a first duration and the second time
slices are of a second duration. The power control unit may determine the
duration for the first and second time slices based on one or more factors
including user charging preferences, device priority, battery charge state, thermal
10 information, or other suitable factors related to providing wireless power to a load.
The thermal information may be associated with the power reception apparatuses,
the interface surface, the primary coil, or any combination thereof.
[0041] In some implementations, the wireless power transmission apparatus
may include a single power control unit to control a plurality of primary coils.
15 The power control unit may use time division multiplexing to control one or more
of the primary coils and deliver wireless power to one or more power wireless
power reception apparatuses. For example, during the first time slices, the power
control unit may cause the first primary coil to transmit wireless power to a first
wireless power reception apparatus. During the second time slices, the power
20 control unit may cause a second primary coil to transmit wireless power to the
corresponding second wireless power reception apparatus. The first and second
time slices may be interspersed so that provision of wireless power alternates
between the first and second wireless power receiving apparatus.
[0042] In some implementations, the wireless power transmission apparatus
25 may include multiple power control units to control multiple primary coils. When
charging a single wireless power reception apparatus, multiple power control units
may cooperatively provide more wireless power to the single wireless power
reception apparatus than would be provided using fewer power control units. For
example, two power control units may control a single primary coil to provide
30 more wireless power to a wireless power reception apparatus. If only one power
control unit were to control the single primary coil, less wireless power would be
10
provided. As a result, the wireless power transmission apparatus may utilize
multiple power control units to provide additional wireless power to a wireless
power reception apparatus.
[0043] In some implementations, the wireless power transmission apparatus
5 may include a user interface to present content related to charging one or more
wireless power reception apparatuses. The user interface may include
components suitable for presenting the content, such as display devices and audio
presentation devices. The content may indicate charging status of a particular
wireless power reception apparatus, faults arising during charging of a particular
10 wireless power reception apparatus, status of a wireless power reception apparatus
waiting for the charging to continue, whether the wireless power transmission
apparatus is currently transmitting wireless power to a particular wireless power
reception apparatus, or any combination thereof.
[0044] Particular implementations of the subject matter described in this
15 disclosure can be implemented to realize one or more of the following potential
advantages. In some implementations, the described techniques can be used to
reduce thermal loads that may arise when charging of one or more wireless power
reception apparatuses. The thermal loads may be reduced by intermittently
providing wireless power to one or more wireless power reception apparatuses.
20 Reducing thermal loads may reduce charging faults, avoid system failures, and
more quickly charge batteries compared to other types of systems with reduced
charge rates at elevated temperatures.
[0045] Figure 1 shows an example wireless power system that includes a
wireless power transmission apparatus capable of charging multiple wireless
25 power reception apparatuses. The wireless power system 100 includes a wireless
power transmission apparatus 110 which has multiple primary coils 120 including
primary coils 121 and 122. The primary coils 120 may be associated with a
power signal generator 128. Each primary coil 120 may be a wire coil which
transmits wireless power (which also may be referred to as wireless energy).
30 Each primary coil 120 may transmit wireless energy using inductive or magnetic
resonant field. The power signal generator 128 may include components (not
11
shown) to prepare the wireless power. For example, the power signal generator
may include one or more switches, drivers, a series capacitor, or other
components.
[0046] The power signal generator 128, power control unit 132 and other
5 components (not shown) may be collectively referred to as transmitter circuit 130.
Some or all of the transmitter circuit 130 may be embodied as an integrated circuit
(IC) that implements features of this disclosure for intermittently providing
wireless power to one or more wireless power reception apparatuses. The power
control unit 132 may be implemented as a microcontroller, dedicated processor,
10 integrated circuit, application specific integrated circuit (ASIC) or any other
suitable electronic device.
[0047] The power source 180 may provide power to the transmitter circuit
130 in the wireless power transmission apparatus 110. The power source 180 may
convert alternating current (AC) to direct current (DC).
15 [0048] The power control unit 132 may detect the presence or proximity of a
wireless power reception apparatus. For example, the power control unit 132 may
cause the primary coils 120 to periodically transmit a detection signal and
measure for a change in coil current or load that indicates an object near the
primary coil. The power control unit 132 may determine when a wireless power
20 reception apparatus is placed in proximity to one or more primary coils 120. For
example, the power control unit 132 may cause a primary coil 120 to periodically
transmit a detection signal and measure for a change in coil current or load that
indicates an object near the primary coil 120. In some implementations, the
power control unit 132 may detect a ping, wireless communication, load
25 modulation, or the like.
[0049] In the example of Figure 1, the power control unit 132 may detect a
first wireless power reception apparatus 210 at a first primary coil 121. The first
wireless power reception apparatus 210 may include a secondary coil 220. A
wireless power reception apparatus may be any type of device capable of
30 receiving wireless power, including a mobile phone, computer, laptop, peripheral,
gadget, robot, vehicle, or the like. When a wireless power reception apparatus
12
(such as the first wireless power reception apparatus 210) is placed on the wireless
power transmission apparatus 110 near the first primary coil 121, the power
control unit 132 may detect its presence. For example, during a detection phase,
the first primary coil 121 may transmit a detection signal (which also may be
5 referred to as a ping). The coil current at the first primary coil 121 may be
measured to determine whether the coil current has crossed a threshold indicating
an object in the electromagnetic field of the first primary coil 121. If an object is
detected, the power control unit 132 may wait for a handshake signal from the
first wireless power reception apparatus 210 (such as an identification signal or
10 setup signal) to determine whether the object is a wireless power reception
apparatus or a foreign object. The handshake signal may be communicated by the
first wireless power reception apparatus 210 using a series of load changes (such
as load modulations). The load changes may be detectable by a coil voltage or
current sensing circuit and interpreted by the power control unit 132. The power
15 control unit 132 may interpret the variations in the load to recover the
communication from the first wireless power reception apparatus 210. The
communication may include information such as charging level, requested
voltage, received power, receiver power capability, support for a wireless
charging standard, or the like.
20 [0050] The first wireless power reception apparatus 210 may include a
secondary coil 220, a rectifier 230, a receive (RX) controller 240 and an battery
module 250. In some implementations, the battery module 250 may have an
integrated charger (not shown). The secondary coil 220 may generate an induced
voltage based on the received wireless power from the first primary coil 121. A
25 capacitor (not shown) may be in series between the secondary coil 220 and the
rectifier 230. The rectifier 230 may rectify the induced voltage and provide the
rectified voltage to the battery module 250. The battery module 250 may be in the
wireless power reception apparatus 210 or may be an external device that is
coupled by an electrical interface. The battery module 250 may include a charger
30 stage, protection circuits such as a temperature-detecting circuit, and overvoltage
and overcurrent protection circuits. Alternatively, the receive controller 240 may
13
include a battery charging management module to collect and process information
on a charging state of the battery module 250. In some implementations, the
receive controller 240 may be configured to communicate with the power control
unit 132 using load modulation via the secondary coil 220.
5 [0051] In the example of Figure 1, the power control unit 132 may detect the
wireless power reception apparatus 210 at the first primary coil 121. In response,
the power control unit 132 may determine first time slices during which wireless
power will be provided to the wireless power reception apparatus 210. The power
control unit 132 also may determine second time slices during which no wireless
10 power will be provided to the wireless power reception apparatus 210. The first
and second time slices may be interspersed so the first primary coil 121
intermittently provides wireless power to the first wireless power reception
apparatus 210. For example, the first time slices may have a duration of five
minutes and the second time slices may have a duration of two minutes. Based on
15 the time slices, the power control unit 132 may intermittently activate the first
primary coil 121 to provide wireless power during the first time slice (five
minutes) and deactivate the first primary coil 121 so no wireless power is
provided during the second time slice (two minutes). For any suitable number of
first and second time slices, the power control unit 132 may repeatedly alternate
20 between power-on time slices and power-off time slices. In some instances, the
power control unit 132 may determine the number of power-on and power-off
time slices based on information about a battery associated with the first wireless
power reception apparatus 210.
[0052] As another example, the power control unit 132 may detect the second
25 wireless power reception apparatus 260 in addition to the first wireless power
reception apparatus 210. The power control unit 132 may intermittently provide
wireless power to each of the first and second wireless power reception
apparatuses (210 and 260, respectively). For example, the power control unit 132
may determine first time slices during which the first primary coil 121 provides
30 wireless power to the first wireless power reception apparatus 210. Additionally,
the power control unit may determine second time slices during which a second
14
primary coil 122 provides wireless power to the second wireless power reception
apparatus 260. In some instances, the first time slices and the second time slices
may have different durations, and the first time slices may be interspersed with the
second time slices. For example, the first time slices may be two minutes in
5 duration, and the second time slices may be three minutes in duration. By
controlling the first and second primary coils (121 and 122, respectively)
according to the interspersed first and second time slices, the power control unit
132 may cause the first primary coil 121 to provide wireless power to the first
wireless power reception apparatus 210 for two minutes. During those two
10 minutes, no power is provided to the second wireless power reception apparatus
260. After the first time slice, the power control unit 132 may provide wireless
power to the second wireless power reception apparatus 260 during the second
time slice, which has a three-minute duration. During those three minutes, no
power is provided to the first wireless power reception apparatus 210. For any
15 suitable number of time slices, the power control unit 132 may intermittently
provide wireless power to the first and second wireless power reception
apparatuses (201 and 260, respectively). The power control unit 132 may control
any suitable number of primary coils to intermittently provide wireless power to
any suitable number of wireless power reception apparatuses.
20 [0053] The power control unit 132 may customize any suitable aspect of the
wireless power. In some instances, the power control unit 132 may determine
wattages, time slice durations, device priorities, device types, and other
information about devices detected on the charging pad. For example, the power
control unit 132 may detect a mobile telephone on the charging pad. For that
25 mobile telephone, the power control unit 132 may select a five-minute power-on
time slice during which wireless power reception apparatus provides 15 Watts
(W) of wireless power. Additionally, the power control unit 132 may select a
two-minute power-off time slice during which wireless power reception apparatus
provides no power. The power control unit 132 may customize power-off time
30 slices based on any suitable information, such as how many devices are on the
15
charging pad, aspects of power-on time slices (such as wattage, duration, etc.) and
device type.
[0054] Figure 2 shows an example wireless power transmission apparatus
having multiple layers of primary coils arranged in an overlapping pattern. The
5 example wireless power transmission apparatus 200 includes 18 primary coils
arranged in two overlapping layers. However, the quantity and arrangement of
primary coils are provided as an example. Other quantities of primary coils,
number of layers, or arrangements may be possible.
[0055] In Figure 2, the power control unit 132 resides at the bottom 151. The
10 first primary coil 121 is shown on the first layer 152, along with several other
primary coils. The second primary coil 122 is shown on the second layer 153
with other primary coils. A combined view 154 shows the coils in overlapping
fashion. Again, this depiction is provided for ease of illustration. In some
implementations, the quantity of coils and overlap may be such that there are few
15 or no dead zones in the charging surface 155. In addition to the wireless power
transmission apparatus 200, Figure 2 shows the first wireless power reception
apparatus 210 and the second wireless power reception apparatus 260 placed on
the charging surface 155. The first wireless power reception apparatus 210 is able
to latch with and receive wireless power from the first primary coil 121 based on
20 its position over that transmitter circuit. Similarly, the second wireless power
reception apparatus 260 may latch with and receive wireless power from the third
primary coil 123.
[0056] Various optional features may be incorporated into the design of the
wireless power transmission apparatus. For example, in some implementations,
25 ferrite material may be used in portions of the wireless power transmission
apparatus to maintain a magnetic field with no (or few) dead zones. In some
implementations, the primary coils may have no overlap. In some
implementations, ferrite material may be used under the primary coils with no
overlap. In some implementations, the shape of the coils, amount of overlap, and
30 materials may be selected to improve efficiency, reduce dead zones, or both.
16
[0057] Although described as a charging pad, the structure of the wireless
power transmission apparatus may be different. For example, the wireless power
transmission apparatus may be located in a vehicle, a piece of furniture, a part of a
wall, a floor, or the like. In some implementations, the wireless power
5 transmission apparatus may be integrated as part of a table-top, coffee table, desk,
counter, or the like.
[0058] Figure 3 is a block diagram illustrating an example wireless power
transmission apparatus. The wireless power transmission apparatus 300 may
include a power source 302. In some implementations, the power source 302 may
10 be an AC-DC converter operating from AC supply mains. In some
implementations, the power source 302 may include a DC-DC power source
operating from a DC input. The power source 302 may provide the DC power to
an inverter 310, which converts the DC power into AC power. The inverter 310
may provide the AC power to a common bus 336. A power control unit 132, a
15 transmitter circuit 318, the transmitter circuit 320, and a transmitter circuit 322
may be connected to and receive power and signals from the common bus 336.
There is a first capacitor 308 connected to the power source 302 and a series
capacitor 312 connected to the common bus 336. For example, the series
capacitor 312 may form a resonant tank with the inductance of the active one of
20 the transmitter circuit 318, 320 or 322.
[0059] The power control unit 132 may receive voltage information from a
first voltage sensor 304 connected to the power source 302 and current
information about current from a first current sensor 306 connected to the power
source 302. The voltage and current information from the first voltage sensor 304
25 and the first current sensor 306, respectively, may be used to compute the power
input to the transmitter apparatus 300. The power control unit 132 also may
receive voltage information from a second voltage sensor 316 connected to the
common bus 336 and current information about current from a second current
sensor 314 connected to the common bus 336. The voltage and current
30 information from the second voltage sensor 316 and the second current sensor
314, respectively, may be used by the power control unit to demodulate the
17
information communicated in the form of packets from the power receiver to the
power transmitter. The power control unit 132 may include one or more driver
units that enable controlling switches 334 in the inverter 310. The switches 334
may be metal-oxide-semiconductor field-effect transistors (MOSFETs) or any
5 other suitable switching devices. The power control unit 132 also may control the
transmitter circuits (318, 320, and 322) via the control lines 330 from their
respective drivers included in the power control unit 132 to enable or disable
switches 340, 344 and 346, respectively.
[0060] The power control unit 132 may determine time slices to control
10 provision of wireless power to wireless power reception apparatuses that may
latch with the transmitter circuits 318, 320 and 322. As described herein, using
the time slices, the power control unit 132 may cause one or more of the
transmitter circuits 318, 320 and 322 to intermittently provide power to one or
more wireless power reception apparatuses. The power control unit 132 may
15 select or otherwise customize various aspects of the wireless power provided to
the wireless power reception apparatuses. For example, the power control unit
132 may determine the time slices and other aspects of the wireless power based
on device priorities, device types, battery charge states, thermal profiles and any
other suitable information relevant to providing wireless power to a load.
20 [0061] The power control unit 132 may be implemented using one or more
microcontrollers, application specific integrated circuits (ASICs), field
programmable gate arrays (FPGAs), microprocessors, or any other suitable
device.
[0062] Figure 4A is an example graphical representation of intermittent
25 wireless power transfer from a wireless power transmission apparatus to a
wireless power reception apparatus. A graph 400 shows a power level during
alternating power-on and power-off time slices. In the graph 400, an X axis
indicates increasing time in minutes, and a Y axis indicates level of power to a
battery charger. The power-on time slices have a duration of five minutes and the
30 power-off time slices have a duration of two minutes. During a first power-on
time slice 402, the power control unit 132 may cause a transmitter circuit to
18
transmit wireless power to a wireless power reception apparatus. During the first
power-on time slice 402, the power level begins at approximately 16 W and
decreases to 12 W over the five-minute duration of the time slice. After the first
power-on time slice 402, there is a first power-off time slice 404. During the first
5 power-off time slice 404, the power level immediately falls to zero because the
power control unit is not providing wireless power to the wireless power reception
apparatus. After the first power-off time slice 404, there is a second power-on
time slice 406. During the second power-on time slice 406, the wireless power
begins at approximately 17 W and decreases to approximately 14 W over the five10 minute duration of the second power-on time slice 406. After the second poweron time slice 406, there is a second power-off time slice during which no wireless
power is provided. As shown, the power control unit 132 may alternate between a
plurality of power-on time slices and a plurality of power-off time slices. For
each of the 16 power-on time slices in the graph 400, the wireless power may
15 begin at a suitable power level and may linearly increase or decrease over the
duration of the power-on time slice. For each of the 15 power-off time slices in
the graph 400, there is no power provided to the charger. By alternating between
power-on and power-off time slices, the wireless power transmission apparatus
may dissipate heat that has accumulated during the power-on time slices.
20 [0063] Figure 4B is an example graphical representation of charging status
resulting from intermittent wireless power transfer between a wireless power
transmission apparatus and a wireless power reception apparatus. A graph 410
shows a curve 412 depicting increasing battery charge over time. In the graph
410, an X axis indicates increasing time in minutes, and a Y axis indicates
25 increasing percentage of battery charge. More specifically, the curve 412 shows
how battery charge may increase when a power control unit provides intermittent
power by alternating between power-on and power-off time slices. In the graph
410, the power-on time slices have a duration of five minutes, and the power-off
time slices have a duration of two minutes. During the first five-minute power-on
30 time slice 414, the battery charge increases from 0% to approximately 5% of a
battery charge capacity. After the first five-minute power-on time slice 414, there
19
is a two-minute power-off time slice 416. During the first two-minute power-off
time slice 416, the battery charge level remains at 5% of battery charge capacity.
After the first two-minute power-off time slice 416, there is a second five-minute
power-on time slice 418. During the second five-minute power-on time slice 418,
5 the battery charge increases to approximately 10% of the battery capacity.
[0064] According to the curve 412, the power control unit may alternate
between 14 additional power-on time slices and 14 additional power-off time
slices. During each of the remaining 14 five-minute power-on time slices, battery
charge percentage increases linearly over the five-minute duration. During each
10 of the remaining 14 two-minute power-off time slices, battery charge does not
increase. After approximately 110 minutes intermittent charging, the curve 412
shows an increase in battery charge up to approximately 80% of battery charge
capacity. The increase in battery charge resulting from intermittent charging may
be very similar to an increase in battery charge that would result from continuous
15 charging. For example, in the same time period (such as approximately 110
minutes), continuous charging may reach approximately 90-100% of battery
charge capacity. In yet other cases, continuous charging may not allow the
transmitter and receiver coils and electronics to operate at full capacity due to
thermal issues. As a result, the charging rate may be much lower and the state of
20 charge may be much lower than 80% of battery capacity in 110 minutes. Thus,
continuous charging does not allow for power-off time slices during which heat
may dissipate. Hence, by providing wireless power in a time sliced fashion, the
power control unit may exhibit charging performance similar to, or sometimes
better than, continuous charging while enabling heat dissipation in components of
25 a wireless charging system. In some implementations, the two minutes of time
available to cool one or more primary coils, one or more secondary coils or an
interface surface may be used by the wireless power transmission apparatus to
energize another primary coil for charging another wireless power receiving
apparatus. As a result, in the time for continuously charging a single wireless
30 power reception apparatus (e.g. 110 minutes), the wireless power transmission
apparatuses described herein may intermittently charge a plurality of wireless
20
power reception apparatuses and achieve better charge states for each as compared
to serially charging those wireless power reception apparatuses on the same
primary coil.
[0065] Figure 5A is an example graphical representation of power-related
5 time slicing associated with charging a single wireless power reception apparatus.
A graph 500 shows an example schedule of time slices. A power control unit 132
may provide wireless power to the wireless power reception apparatus according
to such schedule of time slices. The graph 500 shows the schedule as time moves
forward. According to the schedule of time slices, a first time slice 502 begins at
10 time = 0 and ends at time = 4, where the time units may be seconds, minutes,
hours or any other suitable time metric. Hence, the first time slice 502 has a
duration of four time units. A second time slice 504 has a duration of four time
units, begins at time = 6 and ends at time = 10. A third time slice 506 has a
duration of four time units and begins at time = 12 and ends at time = 16. The
15 time slices 502, 504 and 506 may be power-on time slices during which the power
control unit 132 provides wireless power to a wireless power reception apparatus.
Hence, the scheduled time slices may describe a schedule for wireless power
transfer in which the power control unit 132 causes a transmitter circuit to
transmit wireless power for four time units, cease transmission of the wireless
20 power for two time units, resume transmission of the wireless power for four time
units, and so on.
[0066] The time periods during which power is not transferred (such as from
time = 4 to time = 6) may be considered power-off time slices even though the
power control unit 132 may not explicitly perform operations to determine such
25 power-off time slices. Instead, the power control unit 132 may arrange those
power-on time slices such that there are time gaps between the power-on time
slices. For ease of description, those time gaps may be referred to as power-off
time slices.
[0067] The schedule of time slices can include any suitable type (such as
30 power-on or power-off), number, and duration of time slices. The time slices may
be associated with one or more various power-related parameters, such as a
21
specified a voltage, a specified current, a specified wattage, and any other suitable
power-related parameter. Hence, when providing wireless power according to a
schedule of time slices, the power control unit 132 may customize the wireless
power according to the time slices and their associated parameters.
5 [0068] Time slices associated with a particular device can vary in duration
and can be associated with different power-related parameters. For example, a
schedule for providing wireless power may include power-on time slices having
durations of one minute, two minutes, and five minutes (in any suitable order).
Particular power-related parameters may be associated with particular durations.
10 For example, in some instances one-minute power-on time slices may be
associated with a 15 W power level. Particular power-related parameters (such as
wattage or level of current) also may be associated with other scheduling
attributes such as where the time slots reside in the schedule. For example, a
particular wattage level may be associated with power-on time slices residing in
15 the schedule after the schedule begins.
[0069] Figure 5B is an example graphical representation of power-related
time slicing associated with charging two wireless power reception apparatuses.
A graph 508 shows an example schedule of time slices. A power control unit 132
may provide wireless power to first and second wireless power reception
20 apparatuses according to such a schedule of time slices. The graph 508 shows the
schedule as time moves forward. The graph 508 shows a first time slice 510, a
second time slice 512, a third time slice 514, a fourth time slice 516, and a fifth
time slice 518. These time slices may be power-on time slices during which
wireless power will be provided from a wireless power transmission apparatus.
25 [0070] According to the schedule of time slices, the first time slice 510 is
associated with the first wireless power reception apparatus (referred to as device
1) and begins at time = 0 and ends at time = 4. The time units may be seconds,
minutes, hours or any other suitable time metric. The second time slice 512 is
associated with the second wireless power reception apparatus (referred to as
30 device 2), begins at time = 4 and ends at time = 9. The third time slice 514 is
associated with the first wireless power reception apparatus, begins at time = 9
22
and ends at time = 13. The fourth time slice 516 is associated with the second
wireless power reception apparatus and begins at time = 13 and ends at time = 16.
The fifth time slice 518 is associated with the first wireless power reception
apparatus and begins at time = 16 and ends at time = 20.
5 [0071] The first, third and fifth time slices (510, 514 and 518, respectively)
are associated with the first wireless power reception apparatus and each has a
duration of four time units. The second and fourth time slices (512 and 516,
respectively) are associated with the second wireless power reception apparatus
and each has a different duration. The second time slice 512 has a duration of five
10 time units, and the fourth time slice 516 has a duration of three time units. As the
graph 508 illustrates, the power control unit 132 may determine a schedule for
providing wireless power to multiple wireless power reception apparatuses, where
the schedule includes time slices of different durations for a particular wireless
power reception apparatus. Such a schedule may also include time slices
15 associated with a first wireless power reception apparatus interspersed with time
slices associated with a second wireless power reception apparatus.
[0072] Figure 5C is an example graphical representation of dynamically
updating a schedule of time slices upon detection of an additional wireless power
apparatus. A graph 520 shows an example schedule of time slices. The time
20 slices may be power-on time slices during which wireless power is provided to a
wireless power reception apparatus. Initially, the schedule of time slices may be
identical to the schedule shown in Figure 5A, where the schedule includes time
slices for charging a first wireless power reception apparatus. However, at time =
7, during a time slice 524 associated with the first wireless power reception
25 apparatus (referred to as device 1), a second wireless power reception apparatus
(referred to as device 2) may be placed on the charging pad. In response, the
power control unit 132 may detect the second wireless power reception apparatus
in proximity to a transmitter circuit 130, and dynamically update the schedule to
include time slices for the second wireless power reception apparatus. As shown,
30 the power control unit 132 may determine a time slice 526 associated with the
second wireless power apparatus and insert the time slice 526 into the schedule.
23
In the graph 520, the power control unit 132 does not preempt the time slice 524
associated with the first wireless power reception apparatus. However, in certain
instances, the power control unit 132 may update a schedule in a fashion that
preempts a time slice. Preemption refers to modifying or otherwise abandoning
5 one or more time slices before they have finished in order to proceed with an
updated schedule.
[0073] According to the updated schedule, after completion of the time slice
524, the power control unit 132 may provide power to the second wireless power
reception apparatus during the time slice 526. After time slice 526, the power
10 control unit 132 provides wireless power to the first wireless power reception
apparatus during time slice 528. When determining an updated schedule, the
power control unit 132 may determine any suitable number of new time slices to
be inserted into the updated schedule. The original time slices may be rearranged,
assigned new durations, and otherwise modified (such as by assigning new power
15 -related parameters). The new time slices may have any suitable duration and
may be interspersed with time slices associated with the original schedule.
[0074] The power control unit 132 may create an updated schedule based on
various information. For example, the power control unit 132 may create an
updated schedule based on information about battery charge state, such as
20 information indicating that a particular battery has reached given battery charge
state. In response, the power control unit 132 may reduce the duration of poweron time slices associated with the particular battery and increase the duration of
power-on time slices associated with one or more other devices.
[0075] Figure 6 is a block diagram illustrating a wireless power transmission
25 apparatus 600 in which a power control unit can independently control different
transmitter circuits. As shown, the wireless power transmission apparatus 600
may include a power control unit 132, switch controls lines 618 and 620. In some
implementations, the power control unit 132 may include drivers or other
controllers that are not shown in Figure 6. The wireless power transmission
30 apparatus 600 also may include switches 614 and 616, transmitter circuits 606 and
24
608, and user interfaces 610 and 612. Each of the transmitter circuits 606 and 608
may include a single primary coil or a plurality of primary coils.
[0076] The wireless power transmission apparatus 600 may include a
charging pad 604. The charging pad 604 may include a user interface 610 and a
5 user interface 612. The user interfaces 610 and 612 may present indicia indicating
information related to charging wireless power reception apparatuses. For
example, the user interfaces 610 and 612 each may include light emitting diodes
(LEDs) or liquid crystal displays (LCDs) that indicate device fault status, whether
wireless power is being transmitted to an associated device, or whether a device is
10 waiting to receive wireless power. As shown, the wireless power transmission
apparatus 600 includes a user interface for with each transmitter circuit.
However, the wireless power transmission apparatus 600 may include a single
user interface irrespective of the number of transmitter circuits. The user
interfaces 610 and 612 may include one or more light presentation devices (such
15 as LEDs, LCDs, etc.), audio presentation devices (such as audio monitors), video
presentation devices (such as video monitors), and any other suitable device for
presenting information related to charging wireless power reception apparatuses.
[0077] During operation, the power control unit 132 may detect a first
wireless power reception apparatus in proximity to the transmitter circuit 608. In
20 response, the power control unit 132 may determine a schedule of time slices by
which to provide intermittent power to the first wireless power reception
apparatus. After determining the schedule, the power control unit 132 may
commence to providing intermittent power to the wireless power reception
apparatus. To intermittently provide power to the transmitter circuit 608, the
25 power control unit 132 may actuate the switch 614 via the switch control line 618.
Thus, the transmitter circuit 608 may provide wireless power to the first wireless
power reception device. The user interface 612 may present indicia indicating
when wireless power is being transmitted from the transmitter circuit 608, faults
detected during the schedule of time slices, and any other suitable information
30 related to providing the wireless power.
25
[0078] While the power control unit 132 is providing power via the
transmitter circuit 608, the power control unit 132 may detect a second wireless
power reception device in proximity to the transmitter circuit 606. As described
above, the power control unit 132 may update the schedule of time slices to
5 accommodate the newly detected device. After updating the schedule, the power
control unit 132 may cause the transmitter circuits 606 and 608 to intermittently
provide wireless power to both devices according to the updated schedule of time
slices. By intermittently providing power, a single power control unit can provide
power to multiple transmitter circuits and therefore provide wireless power to
10 multiple wireless power reception apparatuses.
[0079] In some instances, instead of providing intermittent power, the power
control unit 132 may cause the wireless power transmission apparatus 602 provide
continuous wireless power to a wireless power reception apparatus. To provide
continuous power, the power control unit 132 may determine a schedule that
15 includes a single time slice during which continuous power is provided to the
wireless power reception apparatus. Therefore, the power control unit 132 may
provide intermittent wireless power or continuous wireless power to the wireless
power reception apparatus.
[0080] The charging pad 604 may include an interface surface upon which
20 wireless power reception apparatuses are placed to receive power. The power
control unit 132 may receive temperature information from one or more
temperature sensors connected to or in proximity of the charging interface. The
power unit 132 also may receive temperature information from wireless power
reception apparatuses as well as the temperature sensors in the transmitter circuits
25 606 and 608. The temperature information may include temperatures of the
charging interface, transmitter coil(s), receiver coil(s), receiver electronics, or any
combination thereof. The power control unit 132 may cease provision of wireless
power based on certain temperature information. For example, the power control
unit 132 may cease providing wireless power by one of the transmitter circuits if
30 the temperature information indicates that at least a thermal limit has been
exceeded. The thermal limit may indicate a maximum acceptable temperature of
26
an area of the interface surface, the receiver coil, the transmitter coil or the
receiver electronics. For example, the thermal limit may indicate a maximum
acceptable temperature of the portion of the charging pad 604 directly above the
transmitter circuit 606. There may be a plurality of thermal limits (also referred to
5 as thresholds) indicating a plurality of maximum acceptable temperatures
associated with each of these components, respectively. For example, the
maximum acceptable temperature of the interface surface may be 45 degrees
Celsius, whereas the temperature threshold of the electronics may be 80 degrees
Celsius. The power control unit 132 may continue providing intermittent or
10 continuous power via one or more other transmitter circuits that are not associated
with excess temperatures.
[0081] The power control unit 132 may cease provision of wireless power
based on battery charge information received from a wireless power reception
apparatus. For example, the power control unit 132 may cease providing wireless
15 power by one of the transmitter circuits if the battery charge information indicates
that a battery charge threshold has been exceeded. For example, if the battery
charge threshold has been exceeded for a device receiving power from the
transmitter circuit 606, the power control unit 132 may cease providing wireless
power to the device. The power control unit 132 may continue providing
20 continuous or intermittent power to other devices via other transmitter circuits.
During this change, the power control unit 132, also may change the schedule of
time slots for providing power to other devices.
[0082] Figure 7 is a block diagram illustrating a wireless power transmission
apparatus 700 in which multiple power control units can cooperatively provide
25 power to a transmitter circuit. As shown, the wireless power transmission
apparatus 700 includes power control units 702 and 704, switches 706, 708 and
709, switch control lines 720, 722, and 724. The corresponding switch drivers
may be located inside the power control units 702 and 704. The wireless power
transmission apparatus 700 also includes transmitter circuits 710 and 712, a
30 charging pad 718, and user interfaces 714 and 716.
27
[0083] Each of the power control units 702 and 704 may operate
independently. For example, each power control unit may detect a device in
proximity to its associated transmitter circuit and provide continuous or
intermittent wireless power to the device. When operating independently, each of
5 the power control units 702 and 704 may utilize any of the techniques described
herein for providing wireless power to a wireless power reception apparatus.
[0084] Each of the power control units 702 and 704 may have their own
power capabilities. For example, each power control unit may be capable of
providing 5W of power to a transmitter circuit. By working together, the power
10 control units 702 and 704 may provide an increased level of power – such as more
power than each would individually provide. For example, by closing the switch
709, the power control units 702 and 704 may cooperatively provide 10 W of
power to the transmitter circuit 710. The power control unit 702 may
intermittently actuate the switch 708 to intermittently provide the increased level
15 of power to the transmitter circuit 710. Alternatively, the power control unit 702
may close the switch 708 to continuously provide the increased level of power to
the transmitter circuit 710. Under these conditions, the power control units 702
and 704 may operate at the same frequency to share the power fed to the
transmitter circuit 710.
20 [0085] The power control units 702 and 704 may provide power to a single
transmitter circuit according to a schedule of time slices. For example, the
schedule of time slices may include first time slices that call for 10 W of power
and second time slices that call for 5 W of power, where the first and second time
slices are interspersed. During the first time slices, the power control units 702
25 and 704 may cooperatively provide 10 W of power to a transmitter circuit 710.
During the second time slices, one of the power control units may individually
provide 5 W of power to the transmitter circuit 710 or 712. As another example,
the power control units 702 and 704 may provide increased power, where a
schedule of time slices may include first time slices that call for 10 W of power
30 and second time slices that call for 0 W of power, where the first and second time
slices are interspersed. During the first time slices, the power control units 702
28
and 704 may cooperatively provide 10 W of power to the transmitter circuit 710.
During the second time slices, neither the power control unit 702 nor 704 provides
power to the transmitter circuit 710. During time slices in which no power is
provided, one of the power control units 702 and 704 may provide power to a
5 different transmitter circuit (such as the transmitter circuit 712).
[0086] In some implementations, one of the power control units 702 and 704
may act as a “superior controller” that determines time slice schedules for
providing wireless power and the other may act as a “subordinate controller” that
cooperatively caries-out the schedules. In some implementations, the power
10 control units 702 and 704 may act as peers that cooperatively determine and carry
out time slice schedules for providing wireless power to power reception
apparatuses.
[0087] Figure 8 is a flow diagram illustrating example operations of a process
for providing wireless power to a wireless power reception apparatus. For
15 brevity, the operations are described as performed by an apparatus. The
operations of the process 800 may be implemented by a wireless power
transmission apparatus as described herein. For example, the process 800 may be
performed by a wireless power transmission apparatus 110 and the power control
unit 132 described with reference to Figure 1, the wireless power transmission
20 apparatus 600 described with reference to Figure 6, or the wireless power
transmission apparatus 700 and the power control units 702 and 704 described
with reference to Figure 7.
[0088] At block 802, the apparatus may detect a first wireless power reception
apparatus in proximity to a first primary coil of the wireless power transmission
25 apparatus.
[0089] At block 804, the apparatus may determine first time slices during
which to power a first primary coil to cause the first primary coil to transmit a first
wireless power to a first wireless power reception apparatus.
[0090] At block 806, the apparatus may transmit, by the first primary coil, the
30 first wireless power to the first wireless power reception apparatus during the first
time slices.
29
[0091] Figure 9 shows a block diagram of an example apparatus for use in
wireless power system according to some implementations. In some
implementations, the apparatus 900 may be a wireless power transmission
apparatus (such as the wireless power transmission apparatus 110) described
5 herein. In some implementations, the apparatus 900 may be an example of the
power control unit 132 described with reference to Figure 1, the wireless power
transmission apparatus 600 described with reference to Figure 6, or the wireless
power transmission apparatus 700 and the power control units 702 and 704
described with reference to Figure 7. The apparatus 900 can include a processor
10 902 (possibly including multiple processors, multiple cores, multiple nodes, or
implementing multi-threading, etc.). The apparatus 900 also can include a
memory 906. The memory 906 may be system memory or any one or more of the
possible realizations of computer-readable media described herein. The apparatus
900 also can include a bus 911 (such as PCI, ISA, PCI-Express,
15 HyperTransport®, InfiniBand®, NuBus,® AHB, AXI, etc.).
[0092] The apparatus 900 may include one or more controller(s) 962
configured to manage multiple primary or secondary coils (such as a coil array
964). In some implementations, the controller(s) 962 can be distributed within the
processor 902, the memory 906, and the bus 911. The controller(s) 962 may
20 perform some or all of the operations described herein. For example, the
controller(s) 962 may be a power controller, such as the power control unit 132
described with reference to Figure 1 or the power controller 538 described with
reference to Figure 5.
[0093] The memory 906 can include computer instructions executable by the
25 processor 902 to implement the functionality of the implementations described
with reference to Figures 1–8. Any one of these functionalities may be partially
(or entirely) implemented in hardware or on the processor 902. For example, the
functionality may be implemented with an application specific integrated circuit,
in logic implemented in the processor 902, in a co-processor on a peripheral
30 device or card, etc. Further, realizations may include fewer or additional
components not illustrated in Figure 9. The processor 902, the memory 906, and
30
the controller(s) 962 may be coupled to the bus 911. Although illustrated as being
coupled to the bus 911, the memory 906 may be coupled to the processor 902.
[0094] Figures 1–9 and the operations described herein are examples meant to
aid in understanding example implementations and should not be used to limit the
5 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.
[0095] The figures, operations, and components described herein are
examples meant to aid in understanding example implementations and should not
10 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.
[0096] 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
15 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 and c, and a combination of a and b and c.
[0097] The various illustrative components, logic, logical blocks, modules,
circuits, operations and algorithm processes described in connection with the
20 implementations disclosed herein may be implemented as electronic hardware,
firmware, software, or combinations of hardware, firmware or software, including
the structures disclosed in this specification and the structural equivalents thereof.
The interchangeability of hardware, firmware and software has been described
generally, in terms of functionality, and illustrated in the various illustrative
25 components, blocks, modules, circuits and processes described above. Whether
such functionality is implemented in hardware, firmware or software depends
upon the particular application and design constraints imposed on the overall
system.
[0098] The hardware and data processing apparatus used to implement the
30 various illustrative components, logics, logical blocks, modules and circuits
described in connection with the aspects disclosed herein may be implemented or
31
performed with a general purpose single- or multi-chip processor, a digital signal
processor (DSP), an application specific integrated circuit (ASIC), a field
programmable gate array (FPGA) or other programmable logic device (PLD),
discrete gate or transistor logic, discrete hardware components, or any
5 combination thereof designed to perform the functions described herein. A
general-purpose processor may be a microprocessor, or, any conventional
processor, controller, microcontroller, or state machine. A processor also may be
implemented as a combination of computing devices, for example, a combination
of a DSP and a microprocessor, multiple microprocessors, one or more
10 microprocessors in conjunction with a DSP core, or any other such configuration.
In some implementations, particular processes, operations and methods may be
performed by circuitry that is specific to a given function.
[0099] As described above, in some aspects of the subject matter described in
this specification can be implemented as software. For example, various
15 functions of components disclosed herein, or various blocks or steps of a method,
operation, process or algorithm disclosed herein can be implemented as one or
more modules of one or more computer programs. Such computer programs can
include non-transitory processor-executable or computer-executable instructions
encoded on one or more tangible processor-readable or computer-readable storage
20 media for execution by, or to control the operation of, a data processing apparatus
including the components of the devices described herein. By way of example,
and not limitation, such storage media may include RAM, ROM, EEPROM, CDROM or other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other medium that may be used to store program code in
25 the form of instructions or data structures. Combinations of the above should also
be included within the scope of storage media.
[0100] 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
30 without departing from the scope of this disclosure. Thus, the claims are not
intended to be limited to the implementations shown herein but are to be accorded
32
the widest scope consistent with this disclosure, the principles and the novel
features disclosed herein.
[0101] Additionally, various features that are described in this specification in
the context of separate implementations also can be implemented in combination
5 in a single implementation. Conversely, various features that are described in the
context 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
10 some cases be excised from the combination, and the claimed combination may
be directed to a subcombination or variation of a subcombination.
[0102] 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
15 illustrated operations be performed, to achieve desirable results. Further, the
drawings may schematically 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,
20 simultaneously, or between any of the 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 program
25 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 transmission apparatus comprising:
a first primary coil of a plurality of primary coils configured to transmit a first
5 wireless power to a first wireless power reception apparatus.
a power control unit configured to
detect the first wireless power reception apparatus in proximity to the first
primary coil of the wireless power transmission apparatus, and
determine first time slices during which to power the first primary coil to
10 cause the first primary coil to transmit the first wireless power to
the first wireless power reception apparatus.
2. The wireless power transmission apparatus of claim 1, where in the power
control unit is further configured to:
determine second time slices during which to cease transmission of the
15 first wireless power to the first wireless power reception apparatus,
wherein the first time slices are interspersed with the second time
slices, and
cause the first primary coil to cease transmission of the first wireless
power to the first wireless power reception apparatus during the
20 second time slices.
3. The wireless power transmission apparatus of claim 2, wherein a battery is
associated with the first wireless power reception apparatus, wherein the battery is
configured to charge up to a percentage of battery capacity in a first time period,
wherein the first time period is substantially similar to a second time period for
25 continuously charging the battery up to the charge percentage.
4. The wireless power transmission apparatus of claim 2, wherein the cessation of
transmission of the first wireless power keeps a temperature below a thermal limit
34
in one or more components selected from a group consisting of an interface
surface, a transmitter coil, a receiver coil, and electronics in the wireless power
transmission apparatus.
5. The wireless power transmission apparatus of claim 1, where in the power
5 control unit is further configured to:
determine, during one or more of the first time slices, that a thermal limit
has been exceeded, and
cease, in response to the determination that thermal limit has been
exceeded, provision of the first wireless power to the first wireless
10 power reception apparatus during the one or more of the first time
slices.
6. The wireless power transmission apparatus of claim 5, wherein the thermal
limit indicates a maximum temperature of an interface surface of the wireless
power transmission apparatus.
15 7. The wireless power transmission apparatus of claim 1, wherein the first
wireless power reception apparatus is associated with a device rating, and wherein
a duration of the first time slices is based, at least in part, on the device rating.
8. The wireless power transmission apparatus of claim 1, wherein
the power control unit is further configured to:
20 detect a second wireless power reception apparatus in proximity to a
second primary coil of the plurality of primary coils, and
determine second time slices during which to power the second primary
coil to cause the second primary coil to transmit a second wireless
power to the second wireless power reception apparatus, wherein
25 the second time slices are interspersed with the first time slices;
and
35
the second primary coil configured to transmit the second wireless power to the
second wireless power reception apparatus.
9. The wireless power apparatus of claim 8, wherein
the power control unit is further configured to:
5 determine that a battery charge threshold associated with the second
wireless power reception apparatus has been exceeded, and
cause the second primary coil to cease transmission of the second wireless
power during one or more of the second time slices in response to
the determination that the battery charge threshold has been
10 exceeded; and
the second primary coil further configured to cease transmission of the second
wireless power to the second wireless power reception apparatus in
response to the determination that the battery charge threshold has been
exceeded.
15 10. The wireless power transmission apparatus of claim 8, wherein each of the
first time slices has a first duration and each of the second time slices has a second
duration, and wherein
the power control unit further configured to
determine a charge state of a battery associated with the second wireless
20 power reception apparatus,
increase the first duration based on the charge state, and
decrease the second duration based on the charge state.
36
11. The wireless power transmission apparatus of claim 8, wherein each of the
first time slices is of a first duration and each of the second time slices is of a
second duration, and wherein
the power control unit further configured to
5 determine a user-configurable charging priority associated with the second
wireless power reception apparatus, and
modify the first duration based on the user-configurable charging priority.
12. The wireless power transmission apparatus of claim 8, further comprising:
a first user interface (UI) configured to present indicia indicating charging status
10 of at least one of the first primary coil and the second primary coil.
13. The wireless power transmission apparatus of claim 1 further comprising:
another power control unit configured to
detect a second wireless power reception apparatus in proximity to a
second primary coil of the plurality of primary coils,
15 determine second time slices during which to power the second primary
coil to cause the second primary coil to transmit a second wireless
power to the second wireless power reception apparatus, and
provide the second wireless power to the second primary coil during the
second time slices; and
20 the second primary coil configured to transmit the second wireless power to the
second wireless power reception apparatus.
14. The wireless power transmission apparatus of claim 13, wherein the second
time slices are interspersed with the first time slices.
15. The wireless power transmission apparatus of claim 1, further comprising:
37
another power control unit configured to power the first primary coil during the
first time slices, wherein the first wireless power is based on power from each of
the power control units.
16. A method for controlling a wireless power transmission apparatus, the
5 method comprising:
detecting, by a power control unit of the wireless power transmission apparatus, a
first wireless power reception apparatus in proximity to a first primary coil
of the wireless power transmission apparatus;
determining, by the power control unit, first time slices during which to power a
10 first primary coil to cause the first primary coil to transmit a first wireless
power to a first wireless power reception apparatus; and
transmitting, by the first primary coil, the first wireless power to the first wireless
power reception apparatus during the first time slices.
17. The method of claim 16, further comprising:
15 determining second time slices during which to cease transmission of the first
wireless power to the first wireless power reception apparatus, wherein the
first time slices are interspersed with the second time slices; and
causing the first primary coil to cease transmission of the first wireless power to
the first wireless power reception apparatus during the second time slices.
20 18. The method of claim 17, wherein a battery is associated with the first wireless
power reception apparatus, wherein the battery is configured to charge up to a first
percentage of battery capacity in a first time period, wherein the first time period
is substantially similar to a second time period for continuously charging the
battery up to the charge percentage.
25
38
19. The method of claim 17, wherein the cessation of transmission of the first
wireless power keeps a temperature below a thermal limit in one or more of an
interface surface, a transmitter coil, a receiver coil, and electronics in the wireless
power transmission apparatus.
5 20. The method of claim 16, further comprising:
determining, during one or more of the first time slices, that a thermal limit has
been exceeded; and
ceasing, in response to the determination that thermal limit has been exceeded,
provision of the first wireless power to the first wireless power reception
10 apparatus during the one or more of the first time slices.
21. The method of claim 20, wherein the thermal limit indicates a maximum
temperature of an interface surface of the wireless power transmission apparatus.
22. The method of claim 16, wherein the first wireless power reception apparatus
is associated with a device rating, and wherein a duration of the first time slices is
15 based, at least in part, on the device rating.
23. The method of claim 16, further comprising:
detecting, by the power control unit, a second wireless power reception apparatus
in proximity to a second primary coil of the wireless power transmission
apparatus;
20 determining, by the power control unit, second time slices during which to power
the second primary coil to cause the second primary coil to transmit a
second wireless power to the second wireless power reception apparatus,
wherein the second time slices are interspersed with the first time slices;
and
25 transmitting, by the second primary coil, the second wireless power to the second
wireless power reception apparatus.
39
24. method of claim 23, further comprising:
determining that a battery charge threshold associated with the second wireless
power reception apparatus has been exceeded, and
causing the second primary coil to cease transmission of the second wireless
5 power during one or more of the second time slices in response to the
determination that the battery charge threshold has been exceeded.
25. The method of claim 23, wherein each of the first time slices has a first
duration and each of the second time slices has a second duration, wherein the
method further comprises:
10 determining, by the power control unit, a charge state of a battery associated with
the second wireless power reception apparatus;
increasing, by the power control unit, the first duration based on the charge state;
and
decreasing, by the power control unit, the second duration based on the charge
15 state.
26. The method of claim 23, wherein each of the first time slices is of a first
duration and each of the second time slices is of a second duration, wherein the
method further comprises:
determining, by the power control unit, a user-configurable charging priority
20 associated with the second wireless power reception apparatus, and
modifying, by the power control unit, the first duration based on the userconfigurable charging priority.
27. The method of claim 23, further comprising:
presenting, by a first user interface, indicia indicating charging status of at least
25 one of the first primary coil and the second primary coil.
40
28. The method of claim 16, further comprising:
detecting, by another power control unit, a second wireless power reception
apparatus in proximity to a second primary coil of the plurality of primary
coils;
5 determining, by the other power control unit, second time slices during which to
power the second primary coil to cause the second primary coil to transmit
a second wireless power to the second wireless power reception apparatus;
and
providing, by the other power control unit, the second wireless power to the
10 second primary coil during the second time slices; and
transmitting, by the second primary coil, the second wireless power to the second
wireless power reception apparatus.
29. The method of claim 28, wherein the second time slices are interspersed with
the first time slices.
15 30. The method of claim 16 further comprising:
powering, by another power control unit, the first primary coil during the first
time slices, wherein the first wireless power is based on power from each
of the power control units.
31. A wireless power transmission apparatus comprising:
20 a first primary coil of a plurality of primary coils configured to transmit a first
wireless power to a first wireless power reception apparatus;
a first power control unit configured to
detect the first wireless power reception apparatus in proximity to the first
primary coil of the wireless power transmission apparatus, and
41
determine first time slices during which to power the first primary coil to
cause the first primary coil to transmit the first wireless power to
the first wireless power reception apparatus; and
a second power control unit configured to
5 determine second time slices during which to power the first primary coil
to cause the first primary coil to increase the first wireless power.
32. The wireless power transmission apparatus of claim 31 further comprising:
a second primary coil of the plurality of primary coils configured to transmit
second wireless power to a second wireless power reception apparatus;
10 wherein the second power control unit is further configured to
determine third time slices during which to power the second primary coil
to cause the second primary coil to transmit the second wireless
power to the second wireless power reception apparatus.
33. The wireless power transmission apparatus of claim 31, the second power
15 control unit further configured to:
determine fourth time slices during which to cease transmission of the
second wireless power to the first wireless power reception
apparatus, wherein the first time slices are simultaneous with the
second time slices.