Method and system for a highly efficient power amplifier utilizing dynamic biasing and predistortion

• US 7,679,449 B2
• Filed: 08/14/2008
• Issued: 03/16/2010
• Est. Priority Date: 12/06/2006
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Behzad, Arya, Afashi, Ali, Magoon, Vikram
• Primary Examiner(s): NGUYEN, PATRICIA T
• Application Number:
  US12/191,938
• Publication Number:
  US 20090033425A1
• Time in Patent Office: 579 Days
• Field of Search: 330/285, 330/136, 330/261, 330/149
• US Class Current: 330/285
• CPC Class Codes: H03F 1/3211 in differential amplifiers
• CPC Class Codes: H03F 1/3241 using predistortion circuits H03F1/3211, H03F1/3217 take precedence
• CPC Class Codes: H03F 1/3247 using feedback acting on predistortion circuits H03F1/3264 takes precedence
• CPC Class Codes: H03F 1/3294 Acting on the real and imaginary components of the input signal
• CPC Class Codes: H03F 2200/102 A non-specified detector of a signal envelope being used in an amplifying circuit
• 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 2203/45112 the biasing of the differential amplifier being controlled from the input or the output signal
• CPC Class Codes: H03F 2203/45244 the differential amplifier contains one or more explicit bias circuits, e.g. to bias the tail current sources, to bias the load transistors
• CPC Class Codes: H03F 2203/45292 the AAC comprising biasing means controlled by the signal
• CPC Class Codes: H03F 2203/45554 the IC comprising one or more coils
• CPC Class Codes: H03F 3/45188 Non-folded cascode stages
• CPC Class Codes: H04B 2001/0425 with linearisation using predistortion

Abstract

Aspects of a method and system for a highly efficient power amplifier (PA) utilizing dynamic biasing and predistortion are presented. Aspects of the system may include a processor that enables computation of a value of a variable bias component of a bias current based on a bias slope value and an amplitude of an envelope input signal. The processor may enable computation of a value of the bias current based on the selected constant bias current component value and the variable bias current component value. A PA may enable generation of an output signal in response to a generated baseband signal by utilizing the bias current to amplify an amplifier input signal. The bias current may be generated based on the envelope input signal. A feedback signal may be generated based on the output signal, which may be used to predistort a subsequent baseband signal.

Claims

1. A method for biasing of a power amplifier circuit, the method comprising:

computing a value for a variable bias current based on a selected bias slope value;

generating an output signal by amplifying an amplifier input signal, wherein a level for said amplifying is determined based on at least said variable bias current, wherein a level for said variable bias current is determined based on said computed value; and

computing a value for a total bias current based on said variable bias current value and a selected value for a constant bias current.

2. The method according to claim 1, comprising generating said constant bias current from individual constant current generator circuits selected from a plurality of constant current generator circuits.

3. The method according to claim 2, comprising selecting said individual constant current generator circuits based on said selected constant bias current value.

4. The method according to claim 2, wherein each of said selected individual constant current generator circuits generates a constant current level.

5. The method according to claim 4, wherein a value for said constant current level is proportional to a constant voltage level, wherein said constant voltage level is input to said each of said selected individual constant current generator circuits.

6. The method according to claim 4, wherein said selected value for said constant bias current is equal to a summation of said constant current level values from said selected individual constant current generator circuits.

7. The method according to claim 1, comprising generating said variable bias current based on an envelope amplitude level.

8. The method according to claim 7, comprising generating said envelope amplitude level based on said amplifier input signal.

9. The method according to claim 1, comprising generating said variable bias current from individual variable current generator circuits selected from a plurality of variable current generator circuits.

10. The method according to claim 9, comprising selecting said individual variable current generator circuits is based on said selected bias slope value.

11. The method according to claim 9, wherein each of said selected individual variable current generator circuits generates a variable current level.

12. The method according to claim 11, wherein a value of said variable current level is proportional to an envelope amplitude level, wherein said envelope amplitude level is input to said each of said selected individual variable current generator circuits.

13. The method according to claim 12, comprising adjusting said variable current level in response to a change in said envelope amplitude level.

14. The method according to claim 11, wherein said variable bias current value is equal to a summation of said variable current level values from said selected individual variable current generator circuits.

15. The method according to claim 1, comprising generating one or more feedback signals based on said generated output signal.

16. The method according to claim 15, comprising predistorting one or more input baseband signals, based on said generated one or more feedback signals.

17. The method according to claim 16, comprising generating one or more subsequent amplifier input signals based on said predistorted one or more input baseband signals.

18. The method according to claim 17, comprising generating one or more subsequent output signals based on said one or more subsequent amplifier input signals.

19. A system for biasing of a power amplifier circuit, the system comprising:

one or more circuits that enable computation of a value for a variable bias current based on a selected bias slope value;

said one or more circuits enable generation of an output signal by amplifying an amplifier input signal, wherein a level for said amplifying is determined based on at least said variable bias current, wherein a level for said variable bias current is determined based on said computed value; and

said one or more circuit enable computation of a value for a total bias current based on said variable bias current value and a selected value for a constant bias current.

20. The system according to claim 19, wherein said one or more circuit enable generation of said constant bias current from individual constant current generator circuits selected from a plurality of constant current generator circuits.

21. The system according to claim 20, wherein said one or more circuit enable selection of said individual constant current generator circuits based on said selected constant bias current value.

22. The system according to claim 20, wherein each of said selected individual constant current generator circuits generates a constant current level.

23. The system according to claim 22, wherein a value for said constant current level is proportional to a constant voltage level, wherein said constant voltage level is input to said each of said selected individual constant current generator circuits.

24. The system according to claim 22, wherein said selected value for said constant bias current is equal to a summation of said constant current level values from said selected individual constant current generator circuits.

25. The system according to claim 19, wherein said one or more circuit enable generation of said variable bias current based on an envelope amplitude level.

26. The system according to claim 25, wherein said one or more circuit enable generation of said envelope amplitude level based on said amplifier input signal.

27. The system according to claim 19, wherein said one or more circuit enable generation of said variable bias current from individual variable current generator circuits selected from a plurality of variable current generator circuits.

28. The system according to claim 27, wherein said one or more circuit enable selection of said individual variable current generator circuits is based on said selected bias slope value.

29. The system according to claim 27, wherein each of said selected individual variable current generator circuits generates a variable current level.

30. The system according to claim 29, wherein a value of said variable current level is proportional to an envelope amplitude level, wherein said envelope amplitude level is input to said each of said selected individual variable current generator circuits.

31. The system according to claim 30, wherein said one or more circuit enable adjustment of said variable current level in response to a change in said envelope amplitude level.

32. The system according to claim 29, wherein said variable bias current value is equal to a summation of said variable current level values from said selected individual variable current generator circuits.

33. The system according to claim 19, wherein said one or more circuit enable generation of one or more feedback signals based on said generated output signal.

34. The system according to claim 33, wherein said one or more circuit enable predistortion of one or more input baseband signals, based on said generated one or more feedback signals.

35. The system according to claim 34, wherein said one or more circuit enable generation of one or more subsequent amplifier input signals based on said predistorted one or more input baseband signals.

36. The system according to claim 35, wherein said one or more circuit enable generation of one or more subsequent output signals based on said one or more subsequent amplifier input signals.