System and method for power detection in a power amplifier

• US 8,385,853 B2
• Filed: 05/08/2008
• Issued: 02/26/2013
• Est. Priority Date: 05/10/2007
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Prikhodko, Dima, Tkachenko, Gene A., Baree, Atiqul, Sprinkle, Steven C., Dicarlo, Paul T.
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US12/116,980
• Publication Number:
  US 20080284520A1
• Time in Patent Office: 1,755 Days
• Field of Search: 455/115.1, 455/115.3, 455/126, 455/127.1, 455/127.2
• US Class Current: 455/115.3
• CPC Class Codes: G01R 21/10 by using square-law characteristics of circuit elements, e.g. diodes, to measure power absorbed by loads of known impedance G01R21/02 takes precedence
• CPC Class Codes: H03F 2200/207 A hybrid coupler being used as power measuring circuit at the output of an amplifier circuit
• CPC Class Codes: H03F 2200/393 A measuring circuit being coupled to the output of an amplifier
• CPC Class Codes: H03F 2200/456 A scaled replica of a transistor being present in an amplifier
• CPC Class Codes: H03F 2200/465 Power sensing
• CPC Class Codes: H03F 3/191 Tuned amplifiers H03F3/193, H03F3/195 take precedence
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04

Abstract

A system for detecting power output of a power amplifier includes a first power detector configured to detect a forward power output of a power amplifier, the first power detector configured to provide a first power detector output, and a second power detector configured to receive a collector parameter signal and detect a collector parameter therefrom, the second power detector also configured to provide a second power detector output.

Claims

1. A system for detecting power output of a power amplifier, the system comprising:

a first power detector configured to detect a forward power output of a power amplifier, the first power detector further configured to provide a first power detector output;

a second power detector configured to receive a collector parameter signal from a collector terminal of a transistor included in the power amplifier, and to detect a collector parameter based on the collector parameter signal, the second power detector further configured to provide a second power detector output; and

a harmonic trap and filter configured to receive the collector parameter signal and to remove harmonics present in the collector parameter signal to obtain a filtered collector parameter signal, the harmonic trap and filter further configured to provide the filtered collector parameter signal to the second power detector.

2. The system of claim 1 wherein the collector parameter signal is a collector voltage signal.

3. The system of claim 1 wherein the collector parameter signal is a collector current signal.

4. The system of claim 1 wherein the first power detector output and the second power detector output are combined to form a combined power detector output.

5. The system of claim 4 wherein the combined power detector output includes a ratio of the first power detector output and the second power detector output, the ratio based on at least one resistance value.

6. The system of claim 1 wherein the first and second power detectors are chosen from a peak power detector and an average power detector.

7. The system of claim 1 wherein the first and second power detectors are diode detectors.

8. The system of claim 1 wherein the first and second power detectors control the output linearity of the power amplifier and the collector voltage of the power amplifier.

9. The system of claim 1 further comprising a third power detector configured to receive a second collector parameter signal from a second collector terminal of a second transistor included in the power amplifier, and to detect a second collector parameter based on the second collector parameter signal, the third power detector further configured to provide a voltage signal based on the second collector parameter to the first power detector output and the second power detector output.

10. The system of claim 1 wherein the filtered collector parameter signal includes only the fundamental signal components of the collector parameter signal.

11. A portable transceiver having a system for detecting power output of a power amplifier, the portable transceiver comprising:

a transmitter operatively coupled to a power amplifier and to a receiver;

a first power detector configured to detect a forward power output of the power amplifier, the first power detector further configured to provide a first power detector output;

a second power detector configured to receive a collector parameter signal from a collector terminal of a transistor included in the power amplifier, and to detect a collector parameter based on the collector parameter signal, the second power detector further configured to provide a second power detector output; and

a harmonic trap and filter configured to receive the collector parameter signal and to remove harmonics present in the collector parameter signal to obtain a filtered collector parameter signal, the harmonic trap and filter further configured to provide the filtered collector parameter signal to the second power detector.

12. The transceiver of claim 11 wherein the collector parameter signal is a collector voltage signal.

13. The transceiver of claim 11 wherein the collector parameter signal is a collector current signal.

14. The transceiver of claim 11 wherein the first power detector output and the second power detector output are combined to form a combined power detector output.

15. The transceiver of claim 14 wherein the combined power detector output includes a ratio of the first power detector output and the second power detector output, the ratio based on at least one resistance value.

16. The transceiver of claim 11 wherein the first and second power detectors control the output linearity of the power amplifier and the collector voltage of the power amplifier.

17. The transceiver of claim 11 wherein the filtered collector parameter includes only the fundamental signal components of the collector parameter signal.

18. A method for detecting power output of a power amplifier, the method comprising:

providing a first power detector output including the forward power output of a power amplifier;

filtering a collector parameter signal developed from a collector parameter of a collector terminal of a transistor included in the power amplifier to remove harmonics present in the collector parameter signal to obtain a filtered collector parameter signal;

providing a second power detector output developed from the filtered collector parameter signal; and

combining the first power detector output and the second power detector output to form a combined power detector output.

19. The method of claim 18 further comprising choosing a resistance value, a ratio of the first power detector output and the second power detector output based at least in part on the resistance value.

20. The method of claim 19 further comprising controlling the output linearity of the power amplifier and the collector voltage of the power amplifier based at least in part on the combined power detector output.

21. The method of claim 19 wherein the filtered collector parameter signal includes only the fundamental signal components of the collector parameter signal.