Envelope tracking with variable compression

• US 8,626,091 B2
• Filed: 07/16/2012
• Issued: 01/07/2014
• Est. Priority Date: 07/15/2011
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: RF Micro Devices Incorporated (Qorvo, Inc.)
• Inventors: Khlat, Nadim, Folkmann, Andrew F., Retz, James M.
• Primary Examiner(s): LE, THANH C
• Application Number:
  US13/550,060
• Publication Number:
  US 20130181774A1
• Time in Patent Office: 540 Days
• Field of Search: 455/91, 455/114.1, 455/114.2, 455/115.1, 455/126, 455/127.1, 455/127.2, 455/127.4, 375/295, 375/296, 375/297, 330/127, 330/129, 330/149
• US Class Current: 455/115.1
• CPC Class Codes: H03F 1/0216 Continuous control
• CPC Class Codes: H03G 3/004 Control by varying the supply voltage

Abstract

Radio frequency (RF) transmitter circuitry, which includes an envelope tracking power supply and an RF power amplifier (PA), is disclosed. The RF PA operates in either a first operating mode or a second operating mode, such that selection of the operating mode is based on compression tolerance criteria. During the first operating mode, the RF PA receives and amplifies an RF input signal using a first compression level. During the second operating mode, the RF PA receives and amplifies the RF input signal using a second compression level, which is greater than the first compression level. The envelope tracking power supply provides an envelope power supply signal to the RF PA. The envelope power supply signal provides power for amplification.

Claims

1. Circuitry comprising control circuitry adapted to select one of a first operating mode and a second operating mode, such that:

an envelope tracking power supply is adapted to provide an envelope power supply signal to a radio frequency (RF) power amplifier (PA); and

the RF PA is adapted to;

operate in the one of the first operating mode and the second operating mode, such that selection of the one of the first operating mode and the second operating mode is based on compression tolerance criteria;

during the first operating mode, receive and amplify an RF input signal using a first compression level; and

during the second operating mode, receive and amplify the RF input signal using a second compression level, which is greater than the first compression level,

wherein the envelope power supply signal provides power for amplification.

2. The circuitry of claim 1 wherein an efficiency of the RF PA is greater during the second operating mode than during the first operating mode.

3. The circuitry of claim 1 wherein:

the RF PA is further adapted to provide an RF transmit signal based on receiving and amplifying the RF input signal using the envelope power supply signal; and

a spectrum degradation of the RF transmit signal is greater during the second operating mode than during the first operating mode.

4. The circuitry of claim 1 further comprising the envelope tracking power supply and the RF PA.

5. The circuitry of claim 1 wherein RF transceiver circuitry comprises the control circuitry.

6. The circuitry of claim 1 wherein:

the control circuitry is further adapted to provide an envelope power supply control signal; and

the envelope tracking power supply is further adapted to provide the envelope power supply signal based on the envelope power supply control signal.

7. The circuitry of claim 6 wherein selection between the first compression level and the second compression level is based on adjusting a magnitude of the envelope power supply control signal.

8. The circuitry of claim 1 wherein selection between the first compression level and the second compression level is based on adjusting a magnitude of the envelope power supply signal.

9. The circuitry of claim 1 wherein selection between the first compression level and the second compression level is based on adjusting a magnitude of the envelope power supply signal and adjusting a bias of the RF PA.

10. The circuitry of claim 1 wherein selection between the first compression level and the second compression level is based on adjusting a bias of the RF PA.

11. The circuitry of claim 1 wherein:

the RF PA is further adapted to provide an RF transmit signal based on receiving and amplifying the RF input signal;

an RF duplex frequency is equal to a difference between an RF carrier frequency of the RF transmit signal and an RF carrier frequency of an RF receive signal; and

the compression tolerance criteria comprises the RF duplex frequency.

12. The circuitry of claim 11 wherein RF front-end circuitry is adapted to provide the RF receive signal, and receive, process, and transmit the RF transmit signal.

13. The circuitry of claim 11 wherein the control circuitry is further adapted to:

select the first operating mode when the RF duplex frequency is less than a duplex threshold; and

select the second operating mode when the RF duplex frequency is greater than the duplex threshold.

14. The circuitry of claim 11 wherein:

the envelope power supply signal has an envelope power supply signal bandwidth; and

the compression tolerance criteria further comprises the envelope power supply signal bandwidth.

15. The circuitry of claim 1 wherein:

the envelope power supply signal has an envelope power supply signal bandwidth; and

the compression tolerance criteria comprises the envelope power supply signal bandwidth.

16. The circuitry of claim 15 wherein the control circuitry is further adapted to:

select the first operating mode when the envelope power supply signal bandwidth is greater than a bandwidth threshold; and

select the second operating mode when the envelope power supply signal bandwidth is less than the bandwidth threshold.

17. The circuitry of claim 16 wherein the bandwidth threshold is equal to about 5 megahertz.

18. The circuitry of claim 16 wherein the bandwidth threshold is equal to about 10 megahertz.

19. The circuitry of claim 1 wherein the second compression level is at least one-half decibel (dB) greater than the first compression level.

20. The circuitry of claim 19 wherein the second compression level is equal to about 1 dB and the first compression level is equal to about 0 dB.

21. The circuitry of claim 1 wherein the RF PA is further adapted to operate in one of a plurality of operating modes, such that:

the plurality of operating modes comprises the first operating mode and the second operating mode;

during the one of the plurality of operating modes, the RF PA is further adapted to receive and amplify the RF input signal using a corresponding one of a plurality of compression levels;

the plurality of compression levels comprises the first compression level and the second compression level; and

selection of the one of the plurality of operating modes is based on the compression tolerance criteria.

22. Circuitry comprising:

an envelope tracking power supply adapted to provide an envelope power supply signal to a radio frequency (RF) power amplifier (PA); and

the RF PA adapted to;

operate in one of a first operating mode and a second operating mode, such that selection of the one of the first operating mode and the second operating mode is based on compression tolerance criteria;

during the first operating mode, receive and amplify an RF input signal using a first compression level; and

during the second operating mode, receive and amplify the RF input signal using a second compression level, which is greater than the first compression level,

wherein the envelope power supply signal provides power for amplification.

23. A method comprising:

selecting one of a first operating mode and a second operating mode;

providing an envelope power supply signal, which provides power for amplification;

operating in the one of the first operating mode and the second operating mode, such that selection of the one of the first operating mode and the second operating mode is based on compression tolerance criteria;

during the first operating mode, receiving and amplifying a radio frequency (RF) input signal using a first compression level; and

during the second operating mode, receiving and amplifying the RF input signal using a second compression level, which is greater than the first compression level.

24. The method of claim 23 further comprising providing an RF transmit signal based on receiving and amplifying the RF input signal, wherein:

an RF duplex frequency is equal to a difference between an RF carrier frequency of the RF transmit signal and an RF carrier frequency of an RF receive signal; and

the compression tolerance criteria comprises the RF duplex frequency.

25. The method of claim 23 wherein:

the envelope power supply signal has an envelope power supply signal bandwidth; and

the compression tolerance criteria comprises the envelope power supply signal bandwidth.