System and method for a variable impedance transmitter path for charging wireless devices

Patent metadata

Field	Value
Publication number	US-10910883-B2
Application number	US-201715653229-A
Country	US
Kind code	B2
Filing date	Jul 18, 2017
Priority date	Jan 12, 2012
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

In one embodiment, a method includes wirelessly coupling a transmitter to a wireless device; determining a first power transfer value of a signal transmitted from the transmitter to the wireless device with a first transmit impedance; determining a second power transfer value of the signal transmitted from the transmitter to the wireless device with a second transmit impedance; and selecting the first transmit impedance based on received power-level information indicating that the first power transfer value is greater than the second power transfer value.

First claim

What is claimed is:

1. A method comprising:
by a transmitting device, receiving from a wireless device power-level information of a signal transmitted from the transmitting device to the wireless device, wherein the power-level information comprises one or more rectification parameters as measured by the wireless device correlated to a power level of the signal, wherein the power-level information is received through a communication channel between the transmitting device and the wireless device using a communication protocol;
by the transmitting device, determining, based on the power-level information, a first power transfer value of the signal transmitted from the transmitting device to the wireless device with a first transmit impedance;
by the transmitting device, determining, based on the power-level information, a second power transfer value of the signal transmitted from the transmitting device to the wireless device with a second transmit impedance;
by the transmitting device, selecting the first transmit impedance based on the power-level information indicating that the first power transfer value determined based on the power-level information measured by the wireless device and received from the wireless device being provided power from the transmitting device is greater than the second power transfer value determined based on the power-level information measured by the wireless device and received from the wireless device being provided power from the transmitting device;
wherein selecting the first transmit impedance includes using a switch to select based on the power-level information measured by the wireless device, at least one specific electrical path among a plurality of electrical paths each having a different transmit impedance.

2. The method of claim 1 , further comprising, by the transmitting device, determining that the first transmit impedance is not optimal for communication with the mobile device and time-interleaving the first transmit impedance with a different transmit impedance more optimal for communication, wherein the time-interleaving comprising switching at different times between a signal transmission to the wireless device using the first transmit impedance and a signal transmission to the wireless device using the different transmit impedance, and wherein the first transmit impedance corresponds to a higher power transfer value between the first power transfer value and the second power transfer value.

3. The method of claim 1 , further comprising
re-determining the first power transfer value of the signal transmitted from the transmitting device to the wireless device with the first transmit impedance;
re-determining the second power transfer value of the signal transmitted from the transmitting device to the wireless device with the second transmit impedance; and
re-selecting one of the first transmit impedance and the second transmit impedance based on the re-determined first power transfer value and the re-determined second power transfer value.

4. The method of claim 3 , wherein the transmitting device is a communication device, and wherein the re-selecting one of the first transmit impedance and the second transmit impedance based on the re-determined first power transfer value and the re-determined second power transfer value comprises re-selecting one of the first transmit impedance and the second transmit impedance based on information about power transfer values shared between the wireless device and the communications device having the transmitter.

5. The method of claim 1 , further comprising wirelessly charging the wireless device using the first transmit impedance.

6. The method of claim 1 , wherein:
the transmitting device further comprises a plurality of electrical paths each having a different impedance.

7. The method of claim 1 , wherein:
the transmitting device is a communications device; and
the transmitting device further comprises an electrical path having a continuously-controllable impedance.

8. A transmitting device comprising:
a transmitter configured to transmit a signal to a wireless device; and
processing circuitry coupled to the transmitter and configured to:
receive from the wireless device power-level information of the signal transmitted from the transmitter to the wireless device, wherein the power-level information comprises one or more rectification parameters as measured by the wireless device correlated to a power level of the signal, wherein the power-level information is received through a communication channel between the transmitting device and the wireless device using a communication protocol;
determine, based on the power-level information, a first power transfer value of the signal transmitted from the transmitter to the wireless device with a first transmit impedance;
determine, based on the power-level information, a second power transfer value of the signal transmitted from the transmitter to the wireless device with a second transmit impedance;
select the first transmit impedance based on the power-level information indicating that the first power transfer value determined based on the power-level information measured by the wireless device and received from the wireless device being provided power from the transmitting device is greater than the second power transfer value determined based on the power-level information measured by the wireless device and received from the wireless device being provided power from the transmitting device;
wherein the processing circuitry is configured to select the first transmit impedance including by being configured to use a switch to select based on the power-level information measured by the wireless device, at least one specific electrical path among a plurality of electrical paths each having a different transmit impedance.

9. The transmitting device of claim 8 , wherein the processing circuitry is further configured to determine that the first transmit impedance is not optimal for communication with the mobile device and time-interleave the first transmit impedance with a different transmit impedance more optimal for communication, wherein the time-interleaving comprising switching at different times between a signal transmission to the wireless device using the first transmit impedance and a signal transmission to the wireless device using the different transmit impedance, and the first transmit impedance corresponds to a higher power transfer value between the first power transfer value and the second power transfer value.

10. The transmitting device of claim 8 , further comprising:
a printed wiring board etched with a plurality of electrical paths, each electrical path having a different transmit impedance, the plurality of electrical paths including one or more passive components for altering a transmit impedance of each electrical path; and
a switch for selecting, from the plurality of electrical paths, a specific electric path.

11. The transmitting device of claim 8 , wherein the transmitter comprises:
a first digital-to-analog converter configured to convert a real digital signal to a real analog signal;
a second digital-to-analog converter configured to convert an imaginary digital signal to an imaginary analog signal;
a first mixer configured to convert the real analog signal into a radiofrequency (RF) domain for controlling an RF phase of the signal transmitted to the wireless device; and
a second mixer configured to convert the imaginary analog signal into the RF domain for controlling the RF phase of the signal transmitted to the wireless device.

12. The transmitting device of claim 8 , further comprising one or

Assignees

• Facebook Inc

Inventors

• Maguire Yael

Classifications

• H02J7/42 Primary

  with electronic devices having internal batteries, e.g. mobile phones · CPC title

• H02J50/40 Primary

  using two or more transmitting or receiving devices (H02J50/50 takes precedence) · CPC title

• H02J50/20

  using microwaves or radio frequency waves · CPC title

• H02J50/80

  involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices · CPC title

• H04B5/0037

  Electricity · mapped topic