WIRELESS COMMUNICATION DEVICE WITH SELF CALIBRATION FEATURE FOR CONTROLLING POWER OUTPUT

• US 20080002786A1
• Filed: 06/30/2006
• Published: 01/03/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: STMicroelectronics International N.V. (STMicroelectronics NV)
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Kerth, Donald A., Sridharan, Srinath
• Granted Patent: US 7,609,781 B2
• Time in Patent Office: Days
• US Class Current: 375/297
• CPC Class Codes: H04B 17/13 of power amplifiers, e.g. gain or non-linearity
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A wireless communication device is disclosed which employs a minimal number of power calibrations to set the output power of the device to a specified output power level. In one embodiment, the disclosed communication device includes a self calibrating feature that sets the output power level during initialization of the device.

Claims

1. A method of calibrating the gain of a transmitter, comprising:

providing a ramp signal to a transmitter including first and second stages, the ramp signal exhibiting a predetermined value among a range of values;

adjusting, by the first stage, a reference signal to exhibit a reference signal value that is approximately equal to the ramp signal predetermined value, the reference signal value and the ramp signal value controlling the gain of the first stage; and

adjusting, by the second stage, power generated by the transmitter to a predetermined power level.

2. The method of claim 1, wherein the predetermined value of the ramp signal is a maximum value among the range of values.

3. The method of claim 1, wherein the range of values and the reference signal value are voltage values.

4. The method of claim 1, wherein the range of values and the reference signal value are current values.

5. The method of claim 1, wherein the first stage includes a variable gain attenuator.

6. The method of claim 1, wherein the second stage includes a variable gain mixer.

7. The method of claim 6, wherein the adjusting by the second stage step further comprises storing, in a memory, a second stage gain value that is found in the adjusting by the second stage step to correspond to the predetermined power level.

8. The method of claim 7, wherein the second stage gain value is a digital voltage gain amplifier word.

9. The method of claim 1, wherein the adjusting by the first stage step is performed during an initialization of the transmitter.

10. The method of claim 1, wherein the adjusting by the second stage step is performed during a factory calibration.

11. A method of calibrating the gain of a transmitter, comprising:

providing a ramp signal to a transmitter including first and second stages, the ramp signal exhibiting a predetermined value among a range of values;

adjusting, by the first stage, a reference signal to exhibit a reference signal value that is approximately equal to the ramp signal predetermined value, the reference signal value and the ramp signal value controlling the gain of the first stage;

adjusting, by the second stage, the gain of the second stage to determine a second stage gain value for which the transmitter generates output power equal to a predetermined power level;

storing, in a memory, a word related to the second stage gain value; and

retrieving, from the memory, the word for use in subsequent operation of the transmitter to set power output equal to the predetermined power level or a power level offset from the predetermined power level.

12. The method of claim 11, wherein the predetermined value of the ramp signal is a maximum value among the range of values.

13. The method of claim 11, wherein the range of values and the reference signal value are voltage values.

14. The method of claim 11, wherein the range of values and the reference signal value are current values.

15. The method of claim 11, wherein the first stage includes a variable gain attenuator.

16. The method of claim 11, wherein the second stage includes a variable gain mixer.

17. The method of claim 11, wherein the adjusting by the first stage step is performed during an initialization of the transmitter.

18. The method of claim 11, wherein the adjusting by the second stage step is performed during a factory calibration.

19. The method of claim 11, wherein the ramp signal exhibits a maximum voltage value among a range of voltage values that when applied to the first stage causes the first stage to exhibit unity gain.

20. The method of claim 11, wherein the ramp signal exhibits a maximum voltage value among a range of voltage values that when applied to the first stage causes the first stage to exhibit a minimum attenuation value among a range of attenuation values.

21. A wireless communication device comprising:

a baseband section; and

a transmitter section, coupled to the baseband section, the transmitter section including a first stage coupled to a second stage, the baseband section supplying a ramp signal to the first stage, the ramp signal exhibiting a predetermined value among a range of values;

the first stage including a reference signal generator that generates a reference signal that is adjusted to exhibit a reference signal value that is approximately equal to the ramp signal predetermined value, the reference signal value and the ramp signal value controlling the gain of the first stage;

the second stage exhibiting adjustable gain wherein the second stage determines a second stage gain value for which the device generates output power equal to a predetermined power level.

22. The wireless communication device of claim 21, wherein the predetermined value of the ramp signal is a maximum value among the range of values.

23. The wireless communication device of claim 21, wherein the range of values and the reference signal value are voltage values.

24. The wireless communication device of claim 21, wherein the range of values and the reference signal value are current values.

25. The wireless communication device of claim 21, wherein the first stage includes a variable gain attenuator.

26. The wireless communication device of claim 21, wherein the second stage includes a variable gain mixer.

27. The wireless communication device of claim 21, further comprising a memory, coupled to the second stage, that stores a word related to the second stage gain value.

28. The wireless communication device of claim 27, wherein the second stage retrieves the word from the memory for use in subsequent operation of the wireless communication device to set power output equal to the predetermined power level or a power level offset from to the predetermined power level.

29. The wireless communication device of claim 21, further comprising an RF amplifier coupled to the transmitter section to provide an RF output signal.