WIRELESS POWER REPEATING
Cross Reference to Related Application
[0001] The present application claims the benefit of the filing date of U.S.
Patent Application No. 14/580,609, filed December 23, 2014, which is incorporated herein by reference.
Technical Field
[0002] This disclosure relates generally to techniques for wireless charging.
Specifically, this disclosure relates to wireless power repeating.
Background Art
[0003] A basic wireless charging system may include a wireless power
transmitter unit (PTU) and a wireless power receiving unit (PRU). For example, a PTU may include a transmit (Tx) coil, and a PRU may include receive (Rx) coil. Magnetic resonance wireless charging may employ a magnetic coupling between the Tx coil and the Rx coil. As computing devices such as wearable computing devices become increasingly popular, wireless charging systems may be implemented as charging systems for the computing devices as opposed, or even in addition, to traditional wired charging systems. However, in some cases, it may be challenging for the PTU to provide a uniform charging space that is simultaneously optimized for laptops, tablets, phones, wearable devices, among others.
Brief Description of the Drawings
[0004] Fig. 1 is block diagram of a PTU to provide power to a PRU through a
wireless power repeater;
[0005] Fig. 2 is an illustration of a perspective view of the wireless power
repeater in a wireless charging environment;
[0006] Fig. 3 is an illustration of a side view of the wireless power repeater
placed on a PTU;

[0007] Fig. 4 is an illustration of a side view of the wireless power repeater
and a second PRU being placed on the PTU;
[0008] Fig. 5 is a diagram illustrating a circuit including a phase shifting
component;
[0009] Fig. 6 is a diagram illustrating a circuit wherein multiple PRUs are
placed on the wireless power repeater;
[0010] Fig. 7 is a diagram illustrating a device to be charged integrating the
wireless power repeater;
[0011] Fig. 8 is a diagram illustrating a circuit that may be implemented when
the wireless power repeater is integrated into the PRU; and
[0012] Fig. 9 is a flow diagram of a method for forming a wireless power
repeater.
[0013] The same numbers are used throughout the disclosure and the figures to
reference like components and features. Numbers in the 100 series refer to features
originally found in Fig. 1; numbers in the 200 series refer to features originally found in
Fig. 2; and so on.
Description of the Aspects
[0014] The present disclosure relates generally to techniques for wireless
charging. Specifically, the techniques described herein include a wireless power repeater. As discussed above, it may be challenging for the PTU to provide a uniform charging space that is simultaneously optimized for laptops, tablets, phones, wearable devices, among others. The techniques described herein include a wireless power repeater that is configured to receive power from the PTU and retransmit the power to a device to be charged including a PRU. In some cases, the repeater may be implemented in a way that increases distributes a magnetic field such that devices to be charged having various shapes may receive power as magnetic flux is received a PRU including a wireless power receiving coil of each device.
[0015] For example, the wireless power repeater may be formed in a concave
bowl shape. In this scenario, the shape of the bowl shaped repeater may distribute

the magnetic field. However, the wireless power repeater need not be bowl shaped. In some cases, as discussed in more detail below, the wireless power repeater may itself be integrated in a device to be charged. In this scenario, the wireless power repeater may be used to provide power to the device to be charged as well as any additional devices to be charged that are near the device to be charged that integrates the wireless power repeater.
[0016] In some cases, the techniques discussed herein may be implemented
using a wireless charging standard protocol, such as the specification provided by Alliance For Wireless Power (A4WP) version 1.2.1, May 07, 2014. A wireless power receiving (Rx) coil may be a component in a power receiving unit (PRU), while a wireless power transmitting (Tx) coil may be a component in a power transmitting unit (PTU), as discussed in more detail below.
[0017] Fig. 1 is block diagram of a PTU to provide power to a PRU through a
wireless power repeater. A PTU 102 may couple to a PRU 104 via magnetic
inductive coupling between resonators 106, and108, as indicated by the arrow 110.
The resonator 106 may be referred to herein as a Tx coil 106 of the PTU 102. The
resonator 108 may be referred to herein as Rx coil 108 of the PRU 104.
[0018] As discussed above, wireless power is provided from the PTU 102 to
the PRU 104 through a wireless power repeater 112. The wireless power repeater
112 may include an Rx coil 114, a Tx coil 116, and a phase shifting component 118.
As current propagates through the Tx coil 106 of the PTU, a magnetic field is
generated having a magnetic flux received at the Rx coil 114 of the wireless power
repeater 112, as indicated at 109. The magnetic flux 109 received at the Rx coil 114
generates a current to be provided to the Tx coil 116 of the wireless power repeater
112. As current is received at the Tx coil 116 of the wireless power repeater,
another magnetic field is generated having magnetic flux, as indicated at 110. The
magnetic flux 110 is received at the Rx coil 108 of the PRU 104.
[0019] The phase shifting component 118 may couple the Rx coil 114 to the
Tx coil 116 of the wireless power repeater 112. The phase shifting component 118 may ensure that an impedance inversion is generated by the wireless power repeater 112. In some cases, the phase shifting component 118 may enable a

constant current source to be provided from the PTU 102. In some cases, the phase shifting component 118 may be configured to enable multiple PRUs, such as the PRU 104 to receive power from the wireless power repeater 112. Examples of the phase shifting component 116 may include an impedance transformer as discussed in more detail below, a transformer, and a quarter wavelength transmission line, among others.
[0020] The Rx coil 108, as well as other components of the PRU 104
discussed below, may be embedded in a device, as indicated at the dashed box 120. The device 120 may be a wearable device, such as a smart watch, smart bracelet, smart necklace, smart glasses, a power propagating device, and the like. As discussed in more detail below in regard to Fig. 7, the wireless power repeater 112 may be integrated within the device 120, and may be configured to both provide power to the device 120, as well as retransmit power to another device (not shown) having a PRU, such as the PRU 104.
[0021] The PRU 104 may include a controller 122 configured to detect current
received at the Rx coil 108 resulting from an inductive coupling between the Tx coil 106, the wireless power repeater 112, and the Rx coil 108. In some cases, the controller 122 may be configured to initiate a wireless data broadcast indicating a resonant frequency of the Rx coil 108.
[0022] The wireless data transmission component may be Bluetooth Low
Energy (BLE) module 124 in some cases. In some cases, the wireless data transmission component may be integrated as operations of the controller 114, a load modulation circuit 126, a direct current to direct current (DC2DC) converter 128, or any combination thereof, wherein the data transmission may be indicated by patterns in the load modulation.
[0023] As illustrated in Fig. 1, the DC2DC converter 128 provides a DC output
to a battery 130, or another current/power consuming component. The DC2DC
converter 130 may convert DC received as a result of the inductive coupling of the
Tx coil 106, the wireless power repeater 112, the Rx coil 108, and a rectifier 132.
[0024] The PTU 102 may include a BLE module 134 configured to
communicate with the BLE module 124. The PTU 102 may also include a current

sensor 136, a controller 138, a power amplifier 140, a DC2DC converter 142, an
oscillator 144, and a matching network 146. The current sensor 136 may be an
ampere meter, a volt meter, or any other meter configured to sense load variations
occurring due to inductive coupling between the PTU 102 and another object, such
as the PRU 104. The current sensor 136 may provide an indication of load change
to the controller 138 of the PTU 102. The controller 138 may power on the power
amplifier 140 configured to receive direct current (DC) from the DC2DC converter
142, and to amplify and oscillate the current. The oscillator 144 may oscillate the
power provided at a given frequency and a matching network 146 may be used to
match the amplified oscillation provided to the resonator 106 of the PTU 102.
[0025] The block diagram of Fig. 1 is not intended to indicate that the PTU
102, the PRU 104, and/or the wireless power repeater 112 are to include all of the
components shown in Fig. 1. Further, the PTU 102, the PRU 104, and/or the
wireless power repeater 112 may include any number of additional components not
shown in Fig. 1, depending on the details of the specific implementation.
[0026] Fig. 2 is an illustration of a perspective view of the wireless power
repeater in a wireless charging environment. A wireless charging environment 200
may include a surface 202, such as a table, as illustrated in Fig. 2. The surface 202
may include a PTU, such as the PTU 102 of Fig. 1 disposed on the surface 202, or
under the surface 202, such that devices may be charged by placing them on or near
the PTU 102. In this example, the wireless power repeater 112 of Fig. 1 is a bowl-
shaped repeater. Turns for the Tx coil 116 of the wireless power repeater 112 are
formed along the concave curve of the bowl shape, and resulting magnetic fields
may be received by various shapes of devices, including the device 120.
[0027] Fig. 3 is an illustration of a side view of the wireless power repeater
placed on a PTU. In Fig. 3, the Tx coil 118 is illustrated as being formed along a bowl shape, similar to the bowl shape of the wireless power repeater 112 discussed above in regard to Fig. 2. The side view 300 of Fig. 3 illustrates the PTU 102 may generate a magnetic field received by the Rx coil 114 of the wireless power repeater generally indicates at 112. Between the Rx coil 114 and the Tx coil 112 of the wireless power repeater 112 is a phase shifting component, such as the phase

shifting component 118 of Fig. 1. The wireless power repeater 112 may retransmit power from the PTU 102 by current propagating through the Tx coil 116, which may be received at the device 120.
[0028] Fig. 4 is an illustration of a side view of the wireless power repeater
and a second PRU being placed on the PTU. The side view 400 of Fig. 4 similar to
the side view of Fig. 3. However, in this example, the PTU 102 may charge another
device 402 having a PRU, as well as the device 112 placed on the wireless power
repeater, generally indicated at 112. Fig. 4 also illustrates that the PTU 102 may be
connected to a plug 402, such as a wall or ground plug.
[0029] Fig. 5 is a diagram illustrating a circuit including a phase shifting
component. Circuits associated with the PTU 102, the PRU 104, and the wireless power repeater 112 is indicated by dashed boxes in Fig. 5. In Fig. 5, an impedance Z2i is associated with a coupling 502 between the PTU 102 and the Rx coil 114 of the wireless power repeater 112. An impedance Z32 is associated with a coupling 504 between the Tx coil 116 of the wireless power repeater 112 and the Rx coil 108 of the PRU 104.
[0030] As discussed above in regard to Fig. 1, the wireless power repeater
112 may include a phase shifting component 118. In some cases, the phase shifting
component 118 includes two capacitors 506 and 508 as well as two inductors 510
and 512. The phase shifting component 118 may be associated with a characteristic
impedance Z0. The phase shifting component 118 may result in a phase shift
measured in fractions of wavelength, with characteristic impedance of Z0, such as a
quarter wavelength phase shift, to convert, or in some cases extend, charging
coverage while maintaining compliance to the A4WP standard mentioned above.
[0031] An equivalent impedance of the wearable device on the passive
repeater is, assuming the wearable coil is tuned to resonance, is presented below in Equation 1.

[0032] In Eq. 1, RL' is a load resistance associated with the device 120 and
the Tx coil 116. The phase shifting component 118 then converts this equivalent load RL'to a load RL"to the Rx coil 114 of the wireless power repeater 112, as indicated by Equation 2.
[0033] The characteristic impedance Z0 of the phase shifting component 118
can be selected to be the same (or very close) to the coupling between the Tx coil 116 and the Rx coil 108, such that Z(fZ32. In other words, by carefully designing the Tx coil 116 and strategically selecting the characteristic impedance Z0of the phase shifting component 118, the wireless power repeater 112 may be configured to convert/extend a charging coverage while maintaining the compliance to A4WP standard.
[0034] Fig. 6 is a diagram illustrating a circuit wherein multiple PRUs are
placed on the wireless power repeater. In some cases, multiple PRUs, such as the
PRU 104 of Fig. 1 may be charged by the wireless power receiver 112. As
illustrated in Fig. 6, the PRU 104 is a first PRU. A second PRU 602 having a Rx coil
604 may be charged at the same time by power transmitted by the Tx coil 116 of the
wireless power repeater indicated in the dashed box 112. The load resistances of
each of the PRUs 104 and 602 are indicated as equivalent loads RL1' and RL2'.
[0035] Similar to Fig. 5, when PRUs 104 and 602 are tuned, the wireless
power repeater 112 will present an equivalent load of RL" to the repeater as illustrated in Equation 3.

[0036] Fig. 7 is a diagram illustrating a device to be charged integrating the
wireless power repeater. As mentioned above, in some cases, the wireless power repeater 112 may be implemented as an integrated component of a device to be

charged, such as the device 120 of Fig. 1. In this case, the device 120 may include
the phase shifting component 118, and may be configured to receive charge for
itself, as well as retransmit power a second device to be charged 702.
[0037] Fig. 8 is a diagram illustrating a circuit that may be implemented when
the wireless power repeater is integrated into the PRU. The circuit 700 illustrates the
wireless power repeater 112 being implemented within a device to be charged, such
as the device 120 of Fig. 1 indicated at the dashed box 120. In this case, power
received from the PTU 102 is propagated from the Tx coil 116 to another device to
be charged, such as the device 702 of Fig. 7, having a Rx coil 802.
[0038] The power received from the PTU 102 at the Rx coil 114 may also be
provided to a rectifier, such as the rectifier 132 of Fig. 1 discussed above. Therefore, the device 120 may charge itself as well as propagate power to be received at another device to be charged 802.
[0039] Fig. 9 is a flow diagram of a method for forming a wireless power
repeater. At block 902, the method 900 may include forming a wireless power receiving coil configured to receive power from a wireless power first transmitting coil of a wireless charger. At block 904, the method may include forming a second wireless power transmitting coil coupled to the wireless power receiving coil, wherein the second wireless power transmitting coil is configured to propagate current resulting in a magnetic field.
[0040] In some cases, the wireless power receiving coil is a first wireless
power receiving coil. In this case, a flux of the magnetic field is to be received at a
second wireless power receiving coil of a device to be charged.
[0041] The method 900 may also include forming a phase shifting component
coupling the wireless power receiving coil to the second wireless power transmitting coil. The phase shifting component is configured to generate an impedance inversion. The impedance inversion enables a constant current to be provided from the wireless charger. In some cases, the phase shifting component is configured to generate a quarter wavelength phase shift. Forming phase shifting component may include forming two inductors and forming two capacitors. Forming the phase shifting component may include coupling the wireless power receiving coil to the

second wireless power transmitting coil via a transformer. Forming the phase shifting component may include coupling the wireless power receiving coil to the second wireless power transmitting coil via a transmission line of a length configured to generate the quarter wavelength phase shift.
[0042] In some cases, the method 900 includes embedding turns of the
second wireless power transmitting coil a curve of a concave shaped device. In this
case, the method 900 may include disposing the wireless power receiving coil is
formed at a bottom or side of the concave shaped device.
[0043] In some cases, the wireless power receiving coil and the second
wireless power receiving coil are formed in a first device to be charged. The first
device to be charged is configured to be charged by the power provided by the first
wireless power transmitting coil, as well as emit the magnetic field at the second
wireless power transmitting coil based on a presence second device to be charged.
[0044] Not all components, features, structures, characteristics, etc. described
and illustrated herein need be included in a particular aspect or aspects. If the specification states a component, feature, structure, or characteristic "may", "might", "can" or "could" be included, for example, that particular component, feature, structure, or characteristic is not required to be included. If the specification or claim refers to "a" or "an" element, that does not mean there is only one of the element. If the specification or claims refer to "an additional" element, that does not preclude there being more than one of the additional element.
[0045] Example 1 includes an apparatus for wireless power repeating. The
apparatus includes a first wireless power receiving coil configured to receive power
from a first wireless power transmitting coil of a wireless charger. The apparatus
also includes a second wireless power transmitting coil coupled to the first wireless
power receiving coil, wherein the second wireless power transmitting coil is
configured to propagate current resulting in a magnetic field.
[0046] Example 1 may include any combination of the cases discussed below.
In some cases, a flux of the magnetic field is configured to be received at a second wireless power receiving coil of a chargeable device. The apparatus may include a phase shifting component coupling the first wireless power receiving coil to the

second wireless power transmitting coil. The phase shifting component is configured
to generate an impedance inversion. In some cases, the wireless charger can be
configured to provide a constant current based on loads associated a presence of
chargeable devices at the second wireless power receiving coil. The phase shifting
component can be configured to generate a quarter wavelength phase shift.
[0047] In some cases, the phase shifting component may include a plurality of
inductors and a plurality of capacitors. In some cases, the phase shifting component comprises a transformer. In some cases, the phase shifting component comprises a transmission line of a length configured to generate the quarter wavelength phase shift. In some cases, the phase shifting component may be any combination of the cases described above.
[0048] In some cases, the apparatus includes a portion having a concave
shape. The wireless power receiving coil may be formed at a bottom or a side of the apparatus. Turns of the second wireless power transmitting coil may be embedded within the curve of the concave shape.
[0049] In some cases, the apparatus is integrated within a first chargeable
device. The first chargeable device may configured to receive charge from the power provided by the first wireless power transmitting coil, and emit the magnetic field at the second wireless power transmitting coil based on a presence second chargeable device.
[0050] Example 2 includes a method. The method includes forming a first
wireless power receiving coil configured to receive power from a first wireless power transmitting coil of a wireless charger. The method also includes forming a second wireless power transmitting coil coupled to the first wireless power receiving coil, wherein the second wireless power transmitting coil is configured to propagate current resulting in a magnetic field.
[0051] Example 2 may include any combination of the cases described below.
In some cases, a flux of the magnetic field is to be received at a second wireless power receiving coil of a chargeable device. In some cases, the method includes forming a phase shifting component coupling the first wireless power receiving coil to the second wireless power transmitting coil, and wherein the phase shifting

component is configured to generate an impedance inversion. The wireless charger
may be configured to provide a constant current based on loads associated a
presence of chargeable devices at the second wireless power receiving coil.
[0052] In some cases, the phase shifting component is configured to generate
a quarter wavelength phase shift. Forming the phase shifting component may include forming multiple capacitors and forming multiple inductors. Forming the phase shifting component may include coupling the wireless power receiving coil to the second wireless power transmitting coil via a transformer. Forming the phase shifting component may include coupling the wireless power receiving coil to the second wireless power transmitting coil via a transmission line of a length configured to generate the quarter wavelength phase shift.
[0053] In some cases, the method includes embedding turns of the second
wireless power transmitting coil a curve of a concave shaped device, and disposing the wireless power receiving coil is formed at a bottom or side of the concave shaped device.
[0054] In some cases, the wireless power receiving coil and the second
wireless power receiving coil are formed in a first chargeable device. The first chargeable device may be configured to receive charge from the power provided by the first wireless power transmitting coil, as well as emit the magnetic field at the second wireless power transmitting coil based on a presence second chargeable device.
[0055] Example 3 includes a system for wireless power repeating. The
system includes a first wireless power receiving coil configured to receive power from a first wireless power transmitting coil of a wireless charger. The system also includes a second wireless power transmitting coil coupled to the first wireless power receiving coil, wherein the second wireless power transmitting coil is configured to propagate current resulting in a magnetic field. The system also includes a phase shifting component coupling the first wireless power receiving coil to the second wireless power transmitting coil.
[0056] Example 3 may include any combination of the cases discussed below.
In some cases, a flux of the magnetic field is configured to be received at a second

wireless power receiving coil of a chargeable device. The phase shifting component
is configured to generate an impedance inversion. In some cases, the wireless
charger can be configured to provide a constant current based on loads associated a
presence of chargeable devices at the second wireless power receiving coil. The
phase shifting component can be configured to generate a quarter wavelength phase
shift.
[0057] In some cases, the phase shifting component may include a plurality of
inductors and a plurality of capacitors. In some cases, the phase shifting component
comprises a transformer. In some cases, the phase shifting component comprises a
transmission line of a length configured to generate the quarter wavelength phase
shift. In some cases, the phase shifting component may be any combination of the
cases described above.
[0058] In some cases, the system includes a portion having a concave shape.
The wireless power receiving coil may be formed at a bottom or a side of the system.
Turns of the second wireless power transmitting coil may be embedded within the
curve of the concave shape.
[0059] In some cases, the system is integrated within a first chargeable
device. The first chargeable device may configured to receive charge from the
power provided by the first wireless power transmitting coil, and emit the magnetic
field at the second wireless power transmitting coil based on a presence second
chargeable device.
[0060] Example 4 includes a method. The method includes forming a first
means for receiving wireless power configured to receive power from a first wireless
power transmitting coil of a wireless charger. The method also includes forming a
second means for transmitting wireless power coupled to the first means for
receiving wireless power, wherein the second means for transmitting wireless power
is configured to propagate current resulting in a magnetic field.
[0061] Example 4 may include any combination of the cases described below.
In some cases, the first and second means are coils of a passive wireless power
repeater. For example, the first means for wireless power receiving may be a Rx

coil, and the second means for wireless power transmitting may be a Tx coil of a wireless power repeater.
[0062] In some cases, a flux of the magnetic field is to be received at a
second wireless power receiving coil of a chargeable device. In some cases, the method includes forming a phase shifting component coupling the first means for receiving wireless power to the second means for transmitting wireless power, and wherein the phase shifting component is configured to generate an impedance inversion. The wireless charger may be configured to provide a constant current based on loads associated a presence of chargeable devices at the second wireless power receiving coil.
[0063] In some cases, the phase shifting component is configured to generate
a quarter wavelength phase shift. Forming the phase shifting component may
include forming multiple capacitors and forming multiple inductors. Forming the
phase shifting component may include coupling the wireless power receiving coil to
the second means for transmitting wireless power via a transformer. Forming the
phase shifting component may include coupling the wireless power receiving coil to
the second means for transmitting wireless power via a transmission line of a length
configured to generate the quarter wavelength phase shift.
[0064] In some cases, the method includes embedding turns of the second
means for transmitting wireless power a curve of a concave shaped device, and disposing the wireless power receiving coil is formed at a bottom or side of the concave shaped device.
[0065] In some cases, the wireless power receiving coil and the second
wireless power receiving coil are formed in a first chargeable device. The first chargeable device may be configured to receive charge from the power provided by the first wireless power transmitting coil, as well as emit the magnetic field at the second means for transmitting wireless power based on a presence second chargeable device.
[0066] Example 5 includes an apparatus for wireless power repeating. The
apparatus includes a first means for receiving wireless power configured to receive power from a first wireless power transmitting coil of a wireless charger. The

apparatus also includes a second means for transmitting wireless power coupled to
the first means for receiving wireless power, wherein the second means for
transmitting wireless power is configured to propagate current resulting in a magnetic
field.
[0067] Example 5 may include any combination of the cases discussed below.
In some cases, the first and second means are coils of a passive wireless power
repeater. For example, the first means for wireless power receiving may be a Rx
coil, and the second means for wireless power transmitting may be a Tx coil of a
wireless power repeater.
[0068] In some cases, a flux of the magnetic field is configured to be received
at a second wireless power receiving coil of a chargeable device. The apparatus
may include a phase shifting component coupling the first means for receiving
wireless power to the second means for transmitting wireless power. The phase
shifting component is configured to generate an impedance inversion. In some
cases, the wireless charger can be configured to provide a constant current based
on loads associated a presence of chargeable devices at the second wireless power
receiving coil. The phase shifting component can be configured to generate a
quarter wavelength phase shift.
[0069] In some cases, the phase shifting component may include a plurality of
inductors and a plurality of capacitors. In some cases, the phase shifting component
comprises a transformer. In some cases, the phase shifting component comprises a
transmission line of a length configured to generate the quarter wavelength phase
shift. In some cases, the phase shifting component may be any combination of the
cases described above.
[0070] In some cases, the apparatus includes a portion having a concave
shape. The wireless power receiving coil may be formed at a bottom or a side of the
apparatus. Turns of the second means for transmitting wireless power may be
embedded within the curve of the concave shape.
[0071] In some cases, the apparatus is integrated within a first chargeable
device. The first chargeable device may configured to receive charge from the
power provided by the first wireless power transmitting coil, and emit the magnetic

field at the second means for transmitting wireless power based on a presence second chargeable device.
[0072] It is to be noted that, although some aspects have been described in
reference to particular implementations, other implementations are possible according to some aspects. Additionally, the arrangement and/or order of circuit elements or other features illustrated in the drawings and/or described herein need not be arranged in the particular way illustrated and described. Many other arrangements are possible according to some aspects.
[0073] In each system shown in a figure, the elements in some cases may
each have a same reference number or a different reference number to suggest that the elements represented could be different and/or similar. However, an element may be flexible enough to have different implementations and work with some or all of the systems shown or described herein. The various elements shown in the figures may be the same or different. Which one is referred to as a first element and which is called a second element is arbitrary.
[0074] It is to be understood that specifics in the aforementioned examples
may be used anywhere in one or more aspects. For instance, all optional features of the computing device described above may also be implemented with respect to either of the methods or the computer-readable medium described herein. Furthermore, although flow diagrams and/or state diagrams may have been used herein to describe aspects, the techniques are not limited to those diagrams or to corresponding descriptions herein. For example, flow need not move through each illustrated box or state or in exactly the same order as illustrated and described herein.
[0075] The present techniques are not restricted to the particular details listed
herein. Indeed, those skilled in the art having the benefit of this disclosure will appreciate that many other variations from the foregoing description and drawings may be made within the scope of the present techniques. Accordingly, it is the following claims including any amendments thereto that define the scope of the present techniques.

Claims
What is claimed is:
1. An apparatus for wireless power repeating, comprising:
a first wireless power receiving coil configured to receive power from a first wireless power transmitting coil of a wireless charger; and
a second wireless power transmitting coil coupled to the first wireless power receiving coil, wherein the second wireless power transmitting coil is configured to propagate current resulting in a magnetic field.
2. The apparatus of claim 1, wherein a flux of the magnetic field is configured to be received at a second wireless power receiving coil of a chargeable device.
3. The apparatus of claim 1, further comprising a phase shifting component coupling the first wireless power receiving coil to the second wireless power transmitting coil, and wherein the phase shifting component is configured to generate an impedance inversion.
4. The apparatus of claim 3, wherein the wireless charger is configured to provide a constant current based on loads associated a presence of chargeable devices at the second wireless power receiving coil.
5. The apparatus of any combination of claims 3-4, wherein the phase shifting component is configured to generate a quarter wavelength phase shift.
6. The apparatus of any combination of claims 3-4, wherein the phase shifting component comprises:
a plurality of inductors; and a plurality of capacitors.

7. The apparatus of any combination of claims 3-4, wherein the phase shifting component comprises a transformer.
8. The apparatus of claim 7, wherein the phase shifting component comprises a transmission line of a length configured to generate the quarter wavelength phase shift.
9. The apparatus of any combination of claims 1-3, wherein the apparatus comprises a portion having a concave shape, and wherein the wireless power receiving coil is formed at a bottom or a side of the apparatus, and wherein turns of the second wireless power transmitting coil are embedded within the curve of the concave shape.
10. The apparatus of any combination of claims 1-3, wherein the apparatus is integrated within a first chargeable device, and wherein the first chargeable device is configured to receive charge from the power provided by the first wireless power transmitting coil, and emit the magnetic field at the second wireless power transmitting coil based on a presence second chargeable device.
11. A method for wireless power repeating, comprising:
forming a first wireless power receiving coil configured to receive power from a first wireless power transmitting coil of a wireless charger; and
forming a second wireless power transmitting coil coupled to the first wireless power receiving coil, wherein the second wireless power transmitting coil is configured to propagate current resulting in a magnetic field.
12. The method of claim 11, wherein a flux of the magnetic field is to be received at a second wireless power receiving coil of a chargeable device.
13. The method of claim 11, further comprising forming a phase shifting component coupling the first wireless power receiving coil to the second wireless

power transmitting coil, and wherein the phase shifting component is configured to generate an impedance inversion.
14. The method of claim 13, wherein the wireless charger is configured to provide a constant current based on loads associated a presence of chargeable devices at the second wireless power receiving coil.
15. The method of any combination of claims 13-14, wherein the phase shifting component is configured to generate a quarter wavelength phase shift.
16. The method of any combination of claims 13-14, wherein forming the phase shifting component comprises:
forming a plurality of inductors; and forming a plurality of capacitors.
17. The method of any combination of claims 13-14, wherein forming the phase shifting component comprises coupling the wireless power receiving coil to the second wireless power transmitting coil via a transformer.
18. The method of claim 17, wherein forming the phase shifting component comprises coupling the wireless power receiving coil to the second wireless power transmitting coil via a transmission line of a length configured to generate the quarter wavelength phase shift.
19. The method of any combination of claims 11-13, further comprising:
embedding turns of the second wireless power transmitting coil a curve of a
concave shaped device; and disposing the wireless power receiving coil is formed at a bottom or side of the concave shaped device.

20. The method of any combination of claims 11-13, wherein the wireless power receiving coil and the second wireless power receiving coil are formed in a first chargeable device, and wherein the first chargeable device is configured to receive charge from the power provided by the first wireless power transmitting coil, as well as emit the magnetic field at the second wireless power transmitting coil based on a presence second chargeable device.
21. A system for wireless power repeating, comprising:
a first means for receiving wireless power configured to receive power from a first wireless power transmitting coil of a wireless charger; and
a second means for transmitting wireless power coupled to the first means for receiving wireless power, wherein the second means for transmitting wireless power is configured to propagate current resulting in a magnetic field; and
a phase shifting component coupling the first means for receiving wireless power to the second means for transmitting wireless power, and wherein the phase shifting component is configured to generate an impedance inversion.
22. The system of claim 21, wherein a flux of the magnetic field is to be received at a second wireless power receiving coil of a chargeable device.
23. The system of any combination of claims 21 -22, wherein the impedance inversion is associated with a quarter wavelength phase shift.
24. The system of any combination of claims 21 -22, wherein a flux of the magnetic field is to be received at a second wireless power receiving coil of a chargeable device, and wherein the phase shifting component is configured to boost power received at the chargeable device.

25. The system of any combination of claims 21 -22, wherein the system is a component of a first chargeable device, and wherein the first chargeable device is configured to be charged by the power provided by the first wireless power transmitting coil, as well as emit the magnetic field at the second means for transmitting wireless power based on a presence second chargeable device.