POWER AMPLIFIER POWER CONTROLLER

• US 20110148519A1
• Filed: 12/18/2009
• Published: 06/23/2011
• Est. Priority Date: 12/18/2009
• Status: Active Grant

• Current Assignee: Quantance, Inc. (Skyworks Solutions Incorporated)
• Original Assignee: Quantance, Inc. (Skyworks Solutions Incorporated)
• Inventors: Drogi, Serge Francois, Vinayak, Vikas, Tomasz, Martin
• Granted Patent: US 8,731,496 B2
• Time in Patent Office: Days
• US Class Current: 330/129
• CPC Class Codes: H03F 2200/204 A hybrid coupler being used at the output of an amplifier circuit
• 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 2200/465 Power sensing
• CPC Class Codes: H03F 3/189 High-frequency amplifiers, e.g. radio frequency amplifiers
• CPC Class Codes: H03F 3/20 Power amplifiers, e.g. Class B amplifiers, Class C amplifiers H03F3/26 - H03F3/30 take precedence
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03G 3/20 Automatic control H03G3/005 takes precedence; combined with volume compression or expansion H03G7/00
• 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 power amplifier power controller in the power amplifier system monitors various operating conditions of the power amplifier, and controls the output transmit power of the power amplifier by coordinated control of both the input drive level to the power amplifier and the gain of the power amplifier. The power amplifier power controller controls the input drive level to the power amplifier so that the input drive level does not change substantially while adjusting the gain of the power amplifier to maximize the transmit power. The power amplifier power controller may also adjust the input drive level by some portion of the overall change required to the power of the power amplifier, while adjusting the gain of the power amplifier by the remaining portion of such overall change.

Claims

1. A power amplifier system, comprising:

a power amplifier configured to receive and amplify an RF input signal including at least amplitude modulation information to generate an RF output signal; and

a power amplifier power controller configured to adjust a gain of the power amplifier while maintaining substantially constant a level of the RF input signal to the power amplifier.

2. The power amplifier system of claim 1, wherein the power amplifier power controller is configured to monitor an impedance mismatch at an output of the power amplifier and adjusts the gain of the power amplifier based on the monitored impedance mismatch.

3. The power amplifier system of claim 2 wherein the power amplifier power controller is configured to adjust the gain of the power amplifier based on a degree of the impedance mismatch.

4. The power amplifier system of claim 3, wherein the power amplifier power controller determines the degree of impedance mismatch according to a ratio of reverse power to forward power of the RF output signal sensed at the output of the power amplifier.

5. The power amplifier system of claim 2 wherein the power amplifier power controller is configured to adjust the gain of the power amplifier based on an angle of the impedance mismatch.

6. The power amplifier system of claim 5, wherein the power amplifier power controller determines the angle of impedance mismatch according to a phase difference between reverse power and forward power of the RF output signal sensed at the output of the power amplifier.

7. The power amplifier system of claim 1, further comprising an input controller configured to provide the RF input signal to the power amplifier, the power amplifier power controller controlling the input controller to maintain substantially constant the level of the RF input signal provided to the power amplifier while adjusting the gain of the power amplifier.

8. The power amplifier system of claim 7, wherein the input controller includes a variable drive circuit configured to adjust the level of the RF input signal provided to the power amplifier responsive to an input drive control signal received from the power amplifier power controller.

9. The power amplifier system of claim 8, wherein the power amplifier power controller includes a variable attenuator configured to attenuate a sensed forward power level of the RF output signal to be provided as the input drive control signal to the variable drive circuit, the power amplifier power controller configured to reduce or increase attenuation of the sensed forward power level as the gain of the power amplifier is reduced or increased, respectively, so as to maintain substantially constant the level of the RF input signal provided to the power amplifier.

10. The power amplifier system of claim 1, wherein the power amplifier power controller is configured to adjust the gain of the power amplifier further based on one or more sensed conditions of the power amplifier.

11. The power amplifier system of claim 10, wherein the sensed conditions include a temperature at which the power amplifier system operates.

12. The power amplifier system of claim 10, wherein the sensed conditions include SAR (Specific Absorption Rate) at which the power amplifier system operates.

13. The power amplifier system of claim 10, wherein the sensed conditions include a condition of an antenna coupled to the power amplifier for transmission of the RF output signal of the power amplifier.

14. The power amplifier system of claim 10, wherein the sensed conditions include current of the power amplifier.

15. A method for controlling a power amplifier system, the method comprising:

receiving and amplifying an RF input signal to a power amplifier to generate an RF output signal, the RF input signal including at least amplitude modulation information; and

adjusting a gain of the power amplifier while maintaining substantially constant a level of the RF input signal to the power amplifier.

16. The method of claim 15, further comprising:

monitoring an impedance mismatch at an output of the power amplifier; and

adjusting the gain of the power amplifier based on the monitored impedance mismatch.

17. The method of claim 16, wherein the gain of the power amplifier is adjusted based on a degree of the impedance mismatch.

18. The method of claim 17, wherein the degree of impedance mismatch is determined according to a ratio of reverse power to forward power of the RF output signal sensed at the output of the power amplifier.

19. The method of claim 16, wherein the gain of the power amplifier is adjusted based upon an angle of the impedance mismatch.

20. The method of claim 19, wherein the angle of impedance mismatch is determined according to a phase difference between reverse power and forward power of the RF output signal sensed at the output of the power amplifier.

21. The method of claim 15, further comprising reducing or increasing attenuation of a sensed forward power level of the RF output signal of the power amplifier to be provided to an input drive controller providing the RF input signal to the power amplifier as the gain of the power amplifier is reduced or increased, respectively, so as to maintain substantially constant the level of the RF input signal to the power amplifier.

22. The method of claim 15, wherein the gain of the power amplifier is adjusted further based on one or more sensed conditions of the power amplifier.

23. The method of claim 22, wherein the sensed conditions include a temperature at which the power amplifier system operates.

24. The method of claim 22, wherein the sensed conditions include SAR (Specific Absorption Rate) at which the power amplifier system operates.

25. The method of claim 22, wherein the sensed conditions include a condition of an antenna coupled to the power amplifier for transmission of the RF output signal of the power amplifier.

26. The method of claim 22, wherein the sensed conditions include current of the power amplifier.

27. A power amplifier system, comprising:

a power amplifier configured to receive and amplify an RF input signal including at least amplitude modulation information to generate an RF output signal;

a power amplifier power controller configured to adjust a gain of the power amplifier based upon one or more sensed conditions of the power amplifier; and

an input controller configured to provide the RF input signal to the power amplifier, the input controller including a variable drive circuit configured to adjust the level of the RF input signal provided to the power amplifier responsive to an input drive control signal received from the power amplifier power controller, wherein;

the power amplifier power controller is configured to reduce or increase attenuation of a sensed forward power level of the RF output signal to be provided as the input drive control signal while reducing or increasing the gain of the power amplifier, respectively, so as to maintain substantially constant the level of the RF input signal provided to the power amplifier.

28. The power amplifier system of claim 27, wherein the power amplifier power controller includes a variable attenuator configured to attenuate the sensed forward power level of the RF output signal.

29. The power amplifier system of claim 27, wherein:

the power amplifier power controller includes an impedance mismatch detector configured to monitor an impedance mismatch at an output of the power amplifier; and

the power amplifier power controller adjusts the gain of the power amplifier based on the impedance mismatch while maintaining substantially constant the level of the RF input signal provided to the power amplifier.

30. The power amplifier system of claim 29, wherein the power amplifier power controller is configured to adjust the gain of the power amplifier based on a degree of the impedance mismatch.

31. The power amplifier system of claim 30, wherein the power amplifier power controller determines the degree of impedance mismatch according to a ratio of reverse power to forward power of the RF output signal sensed at the output of the power amplifier.

32. The power amplifier system of claim 29, wherein the power amplifier power controller is configured to adjust the gain of the power amplifier based on an angle of the impedance mismatch.

33. The power amplifier system of claim 32, wherein the power amplifier power controller determines the angle of impedance mismatch according to a phase difference between reverse power and forward power of the RF output signal sensed at the output of the power amplifier.

34. The power amplifier system of claim 27, wherein the sensed conditions include a temperature at which the power amplifier system operates.

35. The power amplifier system of claim 27, wherein the sensed conditions include SAR (Specific Absorption Rate) at which the power amplifier system operates.

36. The power amplifier system of claim 27, wherein the sensed conditions include a condition of an antenna coupled to the power amplifier for transmission of the RF output signal of the power amplifier.

37. The power amplifier system of claim 27, wherein the sensed conditions include current of the power amplifier.

38. A power amplifier system, comprising:

a power amplifier configured to receive and amplify an RF input signal including at least amplitude modulation information to generate an RF output signal;

a power amplifier power controller configured to adjust a gain of the power amplifier; and

an input controller configured to provide the RF input signal to the power amplifier, wherein;

the power amplifier power controller controls the input controller to adjust a level of the RF input signal provided to the power amplifier while adjusting the gain of the power amplifier, the adjustment of the level of the RF input signal being different from a change in output power of the power amplifier.

39. The power amplifier system of claim 38, wherein the input controller includes a variable drive circuit configured to adjust the level of the RF input signal provided to the power amplifier responsive to an input drive control signal received from the power amplifier power controller, the power amplifier power controller being configured to reduce or increase attenuation of a sensed forward power level of the RF output signal to be provided as the input drive control signal by more than an amount of reduction or increase of the gain of the power amplifier, respectively.

40. The power amplifier system of claim 39, wherein the power amplifier power controller includes a variable attenuator configured to attenuate the sensed forward power level of the RF output signal.

41. The power amplifier system of claim 38, wherein:

the power amplifier power controller includes an impedance mismatch detector configured to monitor an impedance mismatch at an output of the power amplifier; and

the power amplifier power controller adjusts the gain of the power amplifier based on the impedance mismatch.