Method and system for level detector calibration for accurate transmit power control

• US 7,697,903 B2
• Filed: 12/31/2006
• Issued: 04/13/2010
• 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
• Primary Examiner(s): NGUYEN, SIMON
• Application Number:
  US11/618,832
• Publication Number:
  US 20080139145A1
• Time in Patent Office: 1,199 Days
• Field of Search: 4551141-1154, 455126-1273, 375296-297, 375/312
• US Class Current: 455/91
• CPC Class Codes: H03F 3/45183 Long tailed pairs H03F3/4521, H03F3/45237 take precedence
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H04B 17/13 of power amplifiers, e.g. gain or non-linearity
• CPC Class Codes: H04B 2001/0416 having gain or transmission power control
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

Methods and systems for level detector calibration are disclosed and may comprise calibrating a level detector integrated on-chip to eliminate an associated zero input offset voltage utilizing a replica bias circuit with no input ac voltage at the level detector or the replica bias circuit. The offset voltages of the level detector and the replica bias circuit may be combined to eliminate the associated zero input offset voltage of the level detector. The output signal may be generated by a difference of output signals from the level detector and the replica bias circuit. The level detector and the replica bias circuit may be biased utilizing a similar bias voltage. A plurality of known input voltages may be utilized to generate a corresponding plurality of output voltages of the level detector, generating a corrected transfer function that may be used to accurately set a transmitter power level.

Claims

1. A method for controlling a circuit within a transmitter, the method comprising:

cancelling a zero input offset voltage of a level detector integrated on a chip utilizing a replica bias circuit;

calibrating said level detector over a range of input values utilizing a known temperature and supply-voltage independent voltage level; and

controlling an output power of the transmitter based on a corrected level of said level detector.

2. The method according to claim 1, wherein said replica bias circuit receives no input ac voltage.

3. The method according to claim 2, comprising combining an output signal from said level detector and an output signal from said replica bias circuit for eliminating said associated zero input offset voltage of said level detector.

4. The method according to claim 1, wherein said level detector receives no input ac voltage.

5. The method according to claim 1, comprising generating an output signal which is a difference of an output signal from said level detector and an output signal from said replica bias circuit.

6. The method according to claim 1, comprising biasing said level detector integrated said on-chip and said replica bias circuit utilizing a similar bias voltage.

7. The method according to claim 1, comprising in response to receiving a plurality of known input voltages, generating a corresponding plurality of output voltages by said level detector.

8. The method according to claim 7, comprising determining said corrected level of said level detector based on said generated plurality of output voltages and said received corresponding plurality of known input voltages.

9. The method according to claim 7, wherein said received plurality of known reference input voltages are generated by clipping an input VCO signal.

10. The method according to claim 9, comprising buffering said input VCO signal.

11. The method according to claim 10, comprising applying each of said plurality of known reference input voltages to a plurality of buffers utilized for said buffering.

12. A system for controlling a circuit within a transmitter, the system comprising:

one or more circuits comprising a replica bias circuit that cancels a zero input offset voltage of a level detector integrated on a chip;

said one or more circuits calibrates said level detector over a range of input values utilizing a known temperature and supply-voltage independent voltage level; and

said one or more circuits controls an output power of the transmitter based on a corrected level of said level detector.

13. The system according to claim 12, wherein said one or more circuits for detects a similar offset voltage in said replica bias circuit with no input ac voltage.

14. The system according to claim 12, wherein said one or more circuits combines an output signal from said level detector and an output signal from said replica bias circuit to eliminate said associated zero input offset voltage of said level detector.

15. The system according to claim 12, wherein said one or more circuits detects said offset voltage in said level detector with no input ac voltage.

16. The system according to claim 12, wherein said one or more circuits generates an output signal which is a difference of an output signal from said level detector and an output signal from said replica bias circuit.

17. The system according to claim 12, wherein said one or more circuits biases said level detector integrated said on a chip and said replica bias circuit utilizing a similar bias voltage.

18. The system according to claim 12, wherein said one or more circuits generates a plurality of output voltages by said level detector in response to receiving a corresponding plurality of known input voltages.

19. The system according to claim 18, wherein said one or more circuits determines said corrected level of said level detector based on said generated plurality of output voltages and said received corresponding plurality of known input voltages.

20. The system according to claim 18, wherein said one or more circuits generates said received plurality of known reference input voltages by clipping an input VCO signal.

21. The system according to claim 20, wherein said one or more circuits buffers said input VCO signal.

22. The system according to claim 21, wherein said one or more circuits applies each of said plurality of known reference input voltages to a plurality of buffers utilized for said buffering.