NEAR FIELD TRANSMITTERS FOR WIRELESS POWER CHARGING

• US 20170187225A1
• Filed: 02/17/2016
• Published: 06/29/2017
• Est. Priority Date: 12/24/2015
• Status: Active Grant

• Current Assignee: Energous Corporation
• Original Assignee: Energous Corporation
• Inventors: LEABMAN, Michael A., HOSSEINI, Alister
• Granted Patent: US 10,218,207 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals

Abstract

Disclosed is a system including RF circuitry configured to generate an RF signal; a plurality of unit cells configured to receive the RF signal and to cause an RF energy signal having a center frequency to be present within the unit cells; and receiver circuitry configured to charge an electronic device in response to an antenna of the electronic device receiving the RF energy signal when the antenna is tuned to the center frequency and positioned in a near-field distance from one or more of the unit cells.

Claims

1. A method for charging an electronic device, the method comprising:

receiving, by an antenna configured with a bandwidth that includes a center frequency and used to communicate wireless signals, a wireless charging signal operating at the center frequency, the wireless charging signal received from a charging surface positioned in a near-field distance from the antenna; and

responsive to determining that the antenna is receiving a power above a threshold level, routing the received wireless charging signal to a rectifier to convert the wireless charging signal to a power signal.

2. The method of claim 1, wherein the near-field distance is less than about 4 mm.

3. The method of claim 1, wherein the threshold level is approximately 10 mW.

4. The method of claim 1, wherein the threshold level is approximately 25 mW.

5. The method of claim 1, wherein converting the wireless charging signal to a power signal includes:

rectifying the wireless charging signal to produce a rectified signal, and

converting the rectified signal to the power signal.

6. The method of claim 5, wherein the rectifying is performed by a rectifier.

7. The method of claim 5, wherein converting the rectified signal is performed by a voltage converter.

8. The method of claim 1, further comprising:

applying an RF signal to a plurality of unit cells of the charging surface to cause the wireless charging signal to be present within the unit cells of the charging surface; and

leaking the wireless charging signal from one or more of the unit cells of the charging surface to the antenna positioned within the near-field distance from the one or more unit cells.

9. The method of claim 1, wherein the power signal is used to charge a chargeable battery.

10. The method of claim 1, further comprising, in response to receiving the wireless charging signal, causing an alert signal to indicate that the wireless charging signal is being received.

11. A system comprising:

receiver circuitry configured to determine a power from a wireless charging signal received by an antenna used to communicate wireless signals, the wireless charging signal received by the antenna from a charging surface positioned in a near-field distance from the antenna;

comparator circuitry configured to compare the power to a threshold level;

rectifier circuitry configured to rectify the received wireless charging signal to produce a rectified signal;

a voltage converter configured to convert the rectified signal to a voltage to charge a chargeable battery; and

switching circuitry configured to route the received wireless charging signal to the rectifier when the power exceeds the threshold level.

12. The system of claim 11, wherein the near-field distance is less than about 4 mm.

13. The system of claim 11, wherein the threshold level is approximately 10 mW.

14. The system of claim 11, wherein the threshold level is approximately 25 mW.

15. The system of claim 11, wherein the wireless charging signal operates at a center frequency and the antenna is tuned to the center frequency.

16. The system of claim 11, further comprising:

RF circuitry configured to generate an RF signal; and

a charging surface comprising a plurality of unit cells configured to receive the RF signal and to cause the wireless charging signal to be present within the unit cells.

17. The system of claim 16, wherein the wireless charging signal operates at a center frequency and the unit cells of the charging surface are configured to leak the wireless charging signal to the antenna of the electronic device when the antenna is tuned to the center frequency.