Method and system for enhancing efficiency by modulating power amplifier gain

• US 7,729,671 B2
• Filed: 12/31/2006
• Issued: 06/01/2010
• Est. Priority Date: 12/06/2006
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Afsahi, Ali, Behzad, Arya, Magoon, Vikram
• Primary Examiner(s): NGUYEN, SIMON
• Application Number:
  US11/618,871
• Publication Number:
  US 20080137773A1
• Time in Patent Office: 1,248 Days
• Field of Search: 4551271-1273
• US Class Current: 455/127.1
• CPC Class Codes: H03F 1/0277 Selecting one or more amplifiers from a plurality of amplifiers
• CPC Class Codes: H03F 2200/336 A I/Q, i.e. phase quadrature, modulator or demodulator being used in an amplifying circuit
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2203/21145 Output signals are combined by switching a plurality of paralleled power amplifiers to a common output
• CPC Class Codes: H03F 2203/45396 the AAC comprising one or more switches
• CPC Class Codes: H03F 2203/45481 the CSC comprising only a direct connection to the supply voltage, no other components being present
• CPC Class Codes: H03F 2203/45638 the LC comprising one or more coils
• CPC Class Codes: H03F 2203/7236 the gated amplifier being switched on or off by putting into parallel or not, by choosing between amplifiers by (a ) switch(es)
• CPC Class Codes: H03F 3/211 using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03F 3/45188 Non-folded cascode stages
• CPC Class Codes: H03F 3/72 Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04

Abstract

Aspects of a method and system for enhancing efficiency by modulating power amplifier (PA) gain are presented. Aspects of the system may comprise a PA gain modulator that enables modification of an amplitude of a digital baseband signal. A baseband processor may enable computation of a first gain value based on the modification. The baseband processor may enable computation of a second gain value based on the first gain value. A PA may enable generation of an RF output signal based on the modified digital baseband signal and the second gain value.

Claims

1. A method for controlling gain in an amplifier circuit, the method comprising:

modifying an amplitude of a digital baseband signal;

computing a first gain value based on said modifying;

computing a second gain value based on said first gain value; and

generating an RF output signal based on said modified digital baseband signal and said second gain value.

2. The method according to claim 1, wherein a multiplicative product of said first gain value and said second gain value is a constant value.

3. The method according to claim 1, wherein said amplitude of said digital baseband signal is time varying.

4. The method according to claim 1, wherein an amplitude of said modified digital baseband signal is constant.

5. The method according to claim 1, comprising generating quadrature baseband signals based on said modified digital baseband signal.

6. The method according to claim 5, comprising generating an input RF signal based on said generated quadrature baseband signals.

7. The method according to claim 6, comprising generating said input RF signal based on said modified digital baseband signal and a third gain value.

8. The method according to claim 7, wherein said third gain value is a constant value.

9. The method according to claim 6, comprising generating said generated RF output signal based on said generated input RF signal and said second gain value.

10. The method according to claim 9, wherein an amplitude of said generated input RF signal is constant.

11. The method according to claim 1, comprising dynamically adjusting said first gain value based on said amplitude of said digital baseband signal.

12. The method according to claim 11, comprising dynamically adjusting said second gain value in response to said dynamically adjusted said first gain value.

13. The method according to claim 12, wherein a multiplicative product of said first gain value and said second gain value is approximately equal to a multiplicative product of said dynamically adjusted said first gain value and said dynamically adjusted said second gain value.

14. A system for controlling gain in an amplifier circuit, the system comprising:

one or more circuits that are operable to modify an amplitude of a digital baseband signal;

said one or more circuits are operable to compute a first gain value based on said modification;

said one or more circuits are operable to compute a second gain value based on said first gain value; and

said one or more circuits are operable to generate an RF output signal based on said modified digital baseband signal and said second gain value.

15. The system according to claim 14, wherein a multiplicative product of said first gain value and said second gain value is a constant value.

16. The system according to claim 14, wherein said amplitude of said digital baseband signal is time varying.

17. The system according to claim 14, wherein an amplitude of said modified digital baseband signal is constant.

18. The system according to claim 14, wherein said one or more circuits are operable to generate quadrature baseband signals based on said modified digital baseband signal.

19. The system according to claim 18, wherein said one or more circuits are operable to generate an input RF signal based on said generated quadrature baseband signals.

20. The system according to claim 19, wherein said one or more circuits are operable to generate said input RF signal based on said modified digital baseband signal and a third gain value.

21. The system according to claim 20, wherein said third gain value is a constant value.

22. The system according to claim 19, wherein said one or more circuits are operable to generate said generated RF output signal based on said generated input RF signal and said second gain value.

23. The system according to claim 22, wherein an amplitude of said generated input RF signal is constant.

24. The system according to claim 23, wherein said one or more circuits are operable to dynamically adjust said first gain value based on a said amplitude of said digital baseband signal.

25. The system according to claim 24, wherein said one or more circuits are operable to dynamically adjust said second gain value in response to said dynamically adjusted said first gain value.

26. The system according to claim 25, wherein a multiplicative product of said first gain value and said second gain value is approximately equal to a multiplicative product of said dynamically adjusted said first gain value and said dynamically adjusted said second gain value.