Power control scheme for a power amplifier

• US 7,974,596 B2
• Filed: 12/27/2006
• Issued: 07/05/2011
• Est. Priority Date: 09/22/2006
• Status: Active Grant

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Lim, Lysander, Khoury, John, Leung, Vincent, Pehlke, David
• Primary Examiner(s): Nguyen; Duc M
• Application Number:
  US11/646,055
• Publication Number:
  US 20080076378A1
• Time in Patent Office: 1,651 Days
• Field of Search: 455/126, 4551272-1274, 455/115.1, 455/67.11, 455/231
• US Class Current: 455/126
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

In one embodiment, a method includes detecting a power level of a power amplifier coupled to a transceiver during a current burst of a radio communication and providing the detected power level from the power amplifier to the transceiver and controlling a power level of the power amplifier during a next burst based on the detected power level of the current burst.

Claims

1. A method comprising:

receiving, during a first mode of operation, a detected power level of a power amplifier in a transceiver section coupled to the power amplifier via a feedback path coupled between the power amplifier and the transceiver section during a current burst of a radio communication from a mobile station;

calculating, in the transceiver section, a power level of the power amplifier during a next burst of the radio communication based on the detected power level of the current burst, and controlling a power output of a radio frequency (RF) signal provided by the transceiver section to the power amplifier based on the calculation, the transceiver section not including a baseband section; and

receiving, during a second mode of operation, the detected power level in a controller of the power amplifier and controlling transmit power from the power amplifier based thereon.

2. The method of claim 1, further comprising maintaining the power level of the power amplifier for the current burst during the current burst.

3. The method of claim 1, further comprising determining a correction value for a variable gain amplifier of the transceiver section based on the detected power level.

4. The method of claim 3, further comprising determining a control value for the variable gain amplifier based on the correction value, a previous correction value, a threshold level for the detected power level, and a correction value limit.

5. The method of claim 4, further comprising determining the correction value based on a sum of:

a function of a difference between the detected power level and the threshold level; and

the previous correction value.

6. The method of claim 4, further comprising receiving the threshold level and the correction value limit from a baseband processor coupled to the transceiver section.

7. The method of claim 1, further comprising detecting the power level during transmission of a training sequence of the current burst.

8. The method of claim 7, wherein the training sequence is present in a midamble portion of the burst.

9. A transceiver section comprising:

an interface to receive transmit power control information from a processor, wherein the transceiver section is separate from the processor, the processor is a baseband processor;

a memory to store first parameter information for a first burst of a data transmission from the transceiver section;

a controller coupled to the interface and the memory to receive the transmit power control information and the first parameter information and to determine second parameter information for a second burst of the data transmission based on the first parameter information and the transmit power control information, the second burst following the first burst, wherein the controller is to receive, in a first mode of operation, power sample information from a power amplifier coupled to the transceiver section and determine the second parameter information further based on the received power sample information;

circuitry to receive a baseband signal from the processor, modulate the baseband signal, upconvert the modulated baseband signal to an intermediate frequency (IF) signal, and upconvert the IF signal to a radio frequency (RF) signal; and

a controllable amplifier controlled by the second parameter information to output the RF signal from the transceiver section to the power amplifier at a desired power level, wherein in a second mode of operation, the power amplifier is to control transmit power without the power sample information received by the controller.

10. The transceiver section of claim 9, wherein the controller is to sample the power sample information from the power amplifier during a midamble portion of the first burst.

11. The transceiver section of claim 9, wherein the transceiver section is to operate in a closed-loop mode if the power sample information is present, otherwise the transceiver section to operate in an open-loop mode.

12. The transceiver section of claim 9, wherein the controllable amplifier comprises a digital variable gain amplifier (DVGA) to be controlled by the second parameter information during the second burst.

13. The transceiver section of claim 12, wherein the transmit power control information comprises a threshold level for the power amplifier and a maximum correction value.

14. The transceiver section of claim 13, wherein the first parameter information comprises a correction value indicative of an amount of control change for the DVGA and a difference between the power sample information and the threshold level.

15. The transceiver section of claim 14, wherein the controller is to determine the second parameter information according to a first algorithm if the correction value is less than a threshold, otherwise according to a second algorithm.

16. An article comprising a machine-readable medium including instructions that enable a system to:

receive, in a first mode of operation, a detected power level of a first burst of a multi-slot burst communication from a power amplifier (PA) in a transceiver section coupled to the PA via a feedback path coupled between the PA and the transceiver section, the transceiver section not including a baseband section;

determine, in the transceiver section, a power level update for a second burst of the multi-slot burst communication based at least in part on the detected power level of the first burst;

provide the second burst to the PA from the transceiver section responsive to the power level update in the first mode of operation; and

receive, during a second mode of operation, the detected power level in a controller of the power amplifier and control transmit power from the power amplifier based thereon.

17. The article of claim 16, wherein the instructions further enable the system to receive transmit power control information from a processor of the baseband section to the transceiver section, the transmit power control information including a nominal power level.

18. The article of claim 17, wherein the instructions further enable the system to compare, in the transceiver section, the transmit power control information to the detected power level and determine the power level update based at least in part on the comparison.

19. The article of claim 17, wherein the instructions further enable the system to limit the power level update to a predetermined maximum, wherein the predetermined maximum is received from the processor.

20. The article of claim 16, wherein the instructions further enable the system to control a digital variable gain amplifier (DVGA) of the transceiver section to generate the second burst based on the power level update.

21. The article of claim 16, wherein the instructions further enable the system to sample the detected power level during a training sequence within the first burst.

22. A system comprising:

a transceiver having an interface to receive power control information from a processor, wherein the transceiver is separate from the processor and the processor is a baseband processor, a controllable amplifier to amplify a radio frequency (RF) signal responsive to a power control update, and a controller coupled to the interface to, during a first mode of operation, determine the power control update for a succeeding burst of a multi-slot burst communication based on the power control information and feedback information from a power amplifier coupled to the transceiver from a preceding burst of the multi-slot burst communication, the controller to determine the power control update during the preceding burst and to apply the power control update to the controllable amplifier during an inter-burst period between the preceding burst and the succeeding burst;

the power amplifier coupled to the transceiver to provide the feedback information, wherein the power amplifier further includes a controller to, during a second mode of operation, control transmit power from the power amplifier based on the feedback information from the power amplifier; and

an antenna coupled to the power amplifier to transmit the multi-slot burst communication.

23. The system of claim 22, wherein the transceiver is to receive the power control information from the processor in a digital form.

24. The system of claim 22, wherein the controllable amplifier is to be controlled by a first power control update during the preceding burst, wherein the controller is to determine the power control update using the first power control update.