Wireless device with dynamically adjusted maximum transmit powers

• US 9,300,342 B2
• Filed: 04/18/2013
• Issued: 03/29/2016
• Est. Priority Date: 04/18/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Schlub, Robert W., Jiang, Yi, Li, Qingxiang, Jadhav, Digvijay, Fong, Matthew, Mariner, Brian
• Primary Examiner(s): Trinh, Tan H
• Application Number:
  US13/865,578
• Publication Number:
  US 20140315592A1
• Time in Patent Office: 1,076 Days
• Field of Search: 455/522, 455/73, 455/41.2, 455/41.1, 455/572, 455/127.1, 455/69, 455/126, 455/155, 455/123, 455/129, 455/90.2, 455/435.1, 455/84, 455/101, 455/575.7, 455/566, 455/550, 455/13.4, 455/115, 455/550.1, 455/115.1, 343/876, 343/861, 343/860, 343/702, 343/658, 343/566, 324/679, 324/637, 324/658, 340/552, 340/540, 340/573.4, 340/600, 340/635, 370/275, 370/311, 370/297, 370/252, 370/281, 327/517, 345/173
• US Class Current: 1/1
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 1/3838 Arrangements for reducing RF exposure to the user, e.g. by changing the shape of the transceiver while in use
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range

Abstract

An electronic device may be provided with antenna structures. Proximity sensors and other sensors may be used in determining how the electronic device is being operated. Wireless circuitry such as a radio-frequency transmitter associated with a cellular telephone communications band, a wireless local area network band, or other communications band may be used in transmitting radio-frequency signals through the antenna structures at a transmit power. Control circuitry may adjust the wireless circuitry to ensure that the transmit power is capped at a maximum transmit power. The maximum transmit power may be adjusted dynamically by the control circuitry based on data from the proximity sensors, data from a magnetic sensor that detects whether a cover is present on the device, a connector sensor that detects whether the device is coupled to a dock or other accessory, and other sensors.

Claims

1. An electronic device, comprising:

control circuitry;

an antenna;

wireless circuitry that transmits signals through the antenna at a transmit power that is capped at a maximum transmit power level by the control circuitry; and

a proximity sensor that produces a proximity sensor output indicative of whether an external object is adjacent to the antenna, wherein the control circuitry is configured to back off the maximum transmit power by one of at least three different amounts based on the proximity sensor output.

2. The electronic device defined in claim 1 wherein the control circuitry is configured to monitor received signal strength through the antenna and wireless circuitry and wherein the control circuitry is configured to adjust the transmit power based on the received signal strength.

3. The electronic device defined in claim 1 wherein the control circuitry is configured to adjust the transmit power based on received transmit power commands from a wireless base station.

4. The electronic device defined in claim 1 wherein the proximity sensor comprise an antenna-based proximity sensor.

5. The electronic device defined in claim 4 wherein the antenna-based proximity sensor comprises a coupler and phase and magnitude detection circuitry for monitoring antenna impedance variations.

6. The electronic device defined in claim 1 wherein the proximity sensor comprises a capacitive proximity sensor.

7. The electronic device defined in claim 1 further comprising a motion sensor, wherein the control circuitry is configured to back off the maximum transmit power based at least partly on information from the motion sensor.

8. The electronic device defined in claim 1 further comprising a connector sensor, wherein the control circuitry is configured to back off the maximum transmit power based at least partly on information from the connector sensor.

9. The electronic device defined in claim 1 further comprising a magnetic sensor, wherein the control circuitry is configured to back off the maximum transmit power based at least partly on information from the magnetic sensor.

10. The electronic device defined in claim 1 further comprising an additional antenna and an additional proximity sensor, wherein the control circuitry is configured to back off a maximum transmit power for the additional antenna based on proximity sensor output from the additional proximity sensor.

11. An electronic device, comprising:

control circuitry;

antenna structures;

wireless circuitry including power amplifier circuitry that transmits radio-frequency signals through the antenna at a transmit power that is capped at a maximum transmit power level by the control circuitry;

a proximity sensor that produces a proximity sensor output indicative of whether an external object is adjacent to the antenna structures, wherein the control circuitry is configured to back off the maximum transmit power by a first non-zero amount when the proximity sensor output is between a first proximity sensor output level and a second proximity sensor output level and is configured to back off the maximum transmit power by a second non-zero amount when the proximity sensor output is between the second proximity sensor output level and a third proximity sensor output level; and

a magnetic sensor, wherein the control circuitry is configured to back off the maximum transmit power based at least partly on data from the magnetic sensor.

12. The electronic device defined in claim 11 further comprising a connector sensor that detects whether a connector has been connected to the electronic device, wherein the control circuitry is configured to back off the maximum transmit power based at least partly on data from the connector sensor.

13. The electronic device defined in claim 11 further comprising a motion sensor, wherein the control circuitry is configured to adjust the maximum transmit power based at least partly on data from the motion sensor.

14. The electronic device defined in claim 11, wherein the magnetic sensor is configured to identify whether a cover for the electronic device is present over the electronic device and the control circuitry is configured to back off the maximum transmit power based at least partly on whether the magnetic sensor identifies that the cover is present over the electronic device.

15. The electronic device defined in claim 14, wherein the control circuitry is configured to back off the maximum transmit power by the first and second non-zero amounts when the magnetic sensor identifies that the cover is present over the electronic device and the control circuitry is further configured to back off the maximum transmit power by a third non-zero amount that is different from the first and second non-zero amounts when the proximity sensor output is between the first and third proximity sensor output levels and when the magnetic sensor identifies that the cover is not present over the electronic device.

16. An electronic device, comprising:

a first antenna;

a second antenna;

sensor circuitry that gathers proximity sensor data and additional sensor data;

control circuitry; and

wireless circuitry that transmits radio-frequency signals through the first and second antennas at first and second transmit powers capped respectively at first and second maximum transmit powers by the control circuitry, wherein the control circuitry is configured to adjust the first maximum transmit power using a first maximum transmit power backoff scheme in which the first maximum transmit power is reduced by a first set of non-zero amounts based on the proximity sensor data and using a second maximum transmit power backoff scheme in which the first maximum transmit power is reduced by a second set of non-zero amounts based on the proximity sensor data, the second set of non-zero amounts being different from the first set of non-zero amounts, and the control circuitry being further configured to select a given one of the first and second backoff schemes for use based on the additional sensor data.

17. The electronic device defined in claim 16 wherein the control circuitry is configured to back off the first maximum transmit power by a different amount than the second maximum transmit power based on the proximity sensor data.

18. The electronic device defined in claim 17 further comprising at least one capacitive proximity sensor that generates at least part of the proximity sensor data.

19. The electronic device defined in claim 17 further comprising first and second proximity sensors that produce the proximity sensor data.

20. The electronic device defined in claim 19 wherein the control circuitry is configured to apply a first backoff power to the first maximum transmit power based on proximity sensor data from the first proximity sensor and is configured to apply a second backoff power to the second maximum transmit power based on proximity sensor data from the second proximity sensor and wherein the first and second backoff powers are each selected from at least three distinct backoff power values.

21. The electronic device defined in claim 16 further comprising:

a magnetic sensor; and

a connector sensor, wherein the magnetic sensor and the connector sensor generate the additional sensor data.