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

• US 7,492,223 B2
• Filed: 12/31/2006
• Issued: 02/17/2009
• Est. Priority Date: 12/06/2006
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Afsahi, Ali, Behzad, Arya, Magoon, Vikram
• Primary Examiner(s): NGUYEN, PATRICIA T
• Application Number:
  US11/618,877
• Publication Number:
  US 20080136526A1
• Time in Patent Office: 779 Days
• Field of Search: 330/136, 330/261, 330/149
• US Class Current: 330/136
• 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 of a variable bias current component of a bias current based on a selected bias slope value and an amplitude of an envelope input signal;

computing a value of said bias current based on a selected value of a constant bias current component of said bias current and said value of said variable bias current component; and

generating an output signal by amplifying, utilizing said bias current having said computed value, an amplifier input signal, wherein said bias current is generated based on said envelope input signal.

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

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

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 of said constant current level is proportional to a constant input voltage level to said each of said selected individual constant current generator circuits.

6. The method according to claim 4, wherein said value of said constant bias current component 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 component from individual variable current generator circuits selected from a plurality of variable current generator circuits.

8. The method according to claim 7, wherein said selecting said individual variable current generator circuits is based on said selected bias slope value.

9. The method according to claim 7, wherein each of said selected individual variable current generator circuits generates a variable current level.

10. The method according to claim 9, wherein a value of said variable current level is proportional to said amplitude of said envelope input signal to said each of said selected individual variable current generator circuits.

11. The method according to claim 9, wherein said value of said variable bias current component is equal to a summation of said variable current level values from said selected individual variable current generator circuits.

12. The method according to claim 1, comprising adjusting said value of said bias current in response to a change in said amplitude of said envelope input signal.

13. The method according to claim 1, comprising generating at least one feedback signal based on said generated output signal.

14. The method according to claim 13, comprising predistorting at least one input baseband signal, based on said generated at least one feedback signal.

15. The method according to claim 14, comprising generating a subsequent output signal based on said predistorted said at least one input baseband signal.

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

at least one circuit that enables computation of a value of a variable bias current component of a bias current based on a selected bias slope value and an amplitude of an envelope input signal;

said at least one circuit enables computation of a value of said bias current based on a selected value of a constant bias current component of said bias current and said value of said variable bias current component; and

said at least one circuit enables generation of an output signal by amplifying, utilizing said bias current having said computed value, an amplifier input signal, wherein said bias current is generated based on said envelope input signal.

17. The system according to claim 16, wherein said at least one circuit enables generation of said constant bias current component from individual constant current generator circuits selected from a plurality of constant current generator circuits.

18. The system according to claim 17, wherein said selecting said individual constant current generator circuits is based on said selected value of said constant bias current component.

19. The system according to claim 17, wherein each of said selected individual constant current generator circuits generates a constant current level.

20. The system according to claim 19, wherein a value of said constant current level is proportional to a constant input voltage level to said each of said selected individual constant current generator circuits.

21. The system according to claim 19, wherein said value of said constant bias current component is equal to a summation of said constant current level values from said selected individual constant current generator circuits.

22. The system according to claim 16, wherein said at least one circuit enables generation of said variable bias current component from individual variable current generator circuits selected from a plurality of variable current generator circuits.

23. The system according to claim 22, wherein said selecting said individual variable current generator circuits is based on said selected bias slope value.

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

25. The system according to claim 24, wherein a value of said variable current level is proportional to said amplitude of said envelope input signal to said each of said selected individual variable current generator circuits.

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

27. The system according to claim 16, wherein said at least one circuit enables adjustment of said value of said bias current in response to a change in said amplitude of said envelope input signal.

28. The system according to claim 16, wherein said at least one circuit enables generation of at least one feedback signal based on said generated output signal.

29. The system according to claim 28, wherein said at least one circuit enables predistortion of at least one input baseband signal, based on said generated at least one feedback signal.

30. The system according to claim 29, wherein said at least one circuit enables generation of a subsequent output signal based on said predistorted said at least one input baseband signal.