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

• US 7,868,696 B2
• Filed: 03/15/2010
• Issued: 01/11/2011
• 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: Behzad, Arya, Afashi, Ali, Magoon, Vikram
• Primary Examiner(s): NGUYEN, PATRICIA T
• Application Number:
  US12/724,182
• Publication Number:
  US 20100164629A1
• Time in Patent Office: 302 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;

generating a feedback signal based on said output signal;

generating a predistortion signal based on said feedback signal; and

generating a subsequent output signal based on said predistortion signal and said amplifying.

2. The method according to claim 1, comprising generating a subsequent amplifier input signal based on said predistortion signal.

3. The method according to claim 2, comprising generating said subsequent output signal by said amplifying said subsequent amplifier input signal.

4. The method according to claim 1, comprising generating said variable bias current based on said selected bias slope value and an amplitude for said amplifier input signal.

5. The method according to claim 4, comprising generating said variable bias current based on a constant current bias current.

6. The method according to claim 4, wherein said amplitude is a peak amplitude.

7. The method according to claim 4, wherein said value for said variable bias current increases in response to an increase in said amplitude for said amplifier input signal in proportion to said selected bias slope value.

8. The method according to claim 4, wherein said value for said variable bias current decreases in response to a decrease in said amplitude for said amplifier input signal in proportion to said selected bias slope value.

9. The method according to claim 1, comprising measuring a distortion level in said feedback signal.

10. The method according to claim 9, comprising generating said predistortion signal based on said measured distortion level.

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

one or more circuits the 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;

said one or more circuits enable generation of a feedback signal based on said output signal;

said one or more circuits enable generation of a predistortion signal based on said feedback signal; and

said one or more circuits enable generation of a subsequent output signal based on said predistortion signal and said amplifying.

12. The system according to claim 11, wherein said one or more circuits enable generation of a subsequent amplifier input signal based on said predistortion signal.

13. The system according to claim 12, wherein said one or more circuits enable generation of said subsequent output signal by said amplifying said subsequent amplifier input signal.

14. The system according to claim 11, wherein said one or more circuits enable generation of said variable bias current based on said selected bias slope value and an amplitude for said amplifier input signal.

15. The system according to claim 14, wherein said one or more circuits enable generation of said variable bias current based on a constant current bias current.

16. The system according to claim 14, wherein said amplitude is a peak amplitude.

17. The system according to claim 14, wherein said value for said variable bias current increases in response to an increase in said amplitude for said amplifier input signal in proportion to said selected bias slope value.

18. The system according to claim 14, wherein said value for said variable bias current decreases in response to a decrease in said amplitude for said amplifier input signal in proportion to said selected bias slope value.

19. The system according to claim 11, wherein said one or more circuits enable measurement of a distortion level in said feedback signal.

20. The system according to claim 19, wherein said one or more circuits enable generation of said predistortion signal based on said measured distortion level.