Power amplifying circuit with supply adjust to control adjacent and alternate channel power

• US 6,166,598 A
• Filed: 07/22/1999
• Issued: 12/26/2000
• Est. Priority Date: 07/22/1999
• Status: Expired due to Term

• Current Assignee: Motorola Mobility LLC (Lenovo Group Ltd.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Schlueter, David
• Primary Examiner(s): Shingleton, Michael B
• Application Number:
  US09/359,225
• Time in Patent Office: 523 Days
• Field of Search: 330/127, 330/129, 330/149, 455/126, 375/297
• US Class Current: 330/127
• CPC Class Codes: H01Q 11/12 Resonant antennas
• CPC Class Codes: H03F 1/0233 by using a signal derived from the output signal, e.g. bootstrapping the voltage supply
• CPC Class Codes: H03G 3/004 Control by varying the supply voltage
• 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: H03G 3/3047 for intermittent signals, e.g. burst signals
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04L 27/368 adaptive predistortion
• CPC Class Codes: H04W 52/225 Calculation of statistics, e.g. average, variance
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

A power amplifying circuit with supply adjust for control of adjacent and alternate channel power. A power amplifier amplifies an input signal to produce an amplified signal. A peak-to-average detector detects peak levels of the amplified signal and an average level of the amplified signal and produces an indication of the peak levels and the average level. A controller adjusts a supply voltage to the power amplifier responsive to the indication to cause the supply voltage to lower as a difference between the peak levels and the average level increases above a predetermined level and to cause the supply voltage to elevate as the difference decreases below the predetermined level.

Claims

1. A power amplifying circuit comprising:

a power amplifier for amplifying an input signal to produce an amplified signal;

a peak-to-average detector coupled to an output of the power amplifier, the peak-to-average detector to detect peak levels of the amplified signal and an average level of the amplified signal and to provide an indication of the peak levels and an indication of the average level; and

a controller coupled to the peak-to-average detector and the power amplifier, the controller for adjusting a supply voltage to the power amplifier responsive to the indication of the peak levels and the indication of the average level to cause the supply voltage to lower as a peak-to-average ratio of the amplified signal increases above a predetermined level and to cause the supply voltage to elevate as the peak-to-average ratio of the amplified signal decreases below the predetermined level.

2. The power amplifying circuit as in claim 1 wherein the controller adjusts the supply voltage to the power amplifier to cause the supply voltage to lower as a mean peak-to-average ratio of the amplified signal increases above a desired mean peak-to-average ratio and to cause the supply voltage to elevate as the mean peak-to-average ratio of the amplified signal decreases below the desired mean peak-to-average ratio.

3. The power amplifying circuit as in claim 2 wherein the controller causes the power amplifier to maintain the mean peak-to-average ratio substantially equal to the desired mean peak-to-average ratio.

4. The power amplifying circuit as in claim 3 wherein the mean peak-to-average ratio comprises a ratio of an average of the peak levels of the amplified signal to the average level of the amplified signal over a predetermined period of time.

5. The power amplifying circuit as in claim 4 wherein the peak-to-average detector calculates the mean peak-to-average ratio.

6. The power amplifying circuit as in claim 4 wherein the controller calculates the mean peak-to-average ratio.

7. The power amplifying circuit as in claim 1 further comprising a variable gain circuit coupled to an input of the power amplifier, wherein the controller adjusts a gain of the variable gain circuit responsive to the indication of the average level of the amplified signal to cause the average level of the amplified signal to substantially equal a desired average output power.

8. The power amplifying circuit as in claim 1 further comprising a voltage control circuit coupled between the controller and the power amplifier, wherein the controller produces a control signal responsive to the indication of the peak levels and the average power, the voltage control circuit processing the control signal to produce the supply voltage.

9. The power amplifying circuit as in claim 8 wherein the voltage control circuit comprises one of a linear voltage regulator and a switching voltage regulator.

10. A power amplifying circuit for use in a portable radiotelephone, the power amplifying circuit comprising:

a power amplifier for amplifying an input signal to produce an amplified signal;

a peak-to-average detector coupled to an output of the power amplifier, the peak-to-average detector to detect peak levels of the amplified signal and an average power of the amplified signal and to provide an indication of the peak levels and the average power; and

a controller coupled to the peak-to-average detector and the power amplifier, the controller for adjusting a supply voltage to the power amplifier responsive to the indication of the peak levels and the average power to cause the supply voltage to lower as a mean peak-to-average ratio of the amplified signal increases above a desired peak-to-average ratio and to cause the supply voltage to elevate as the mean peak-to-average ratio decreases below the desired peak-to-average ratio.

11. The power amplifying circuit as in claim 10 wherein the controller causes the power amplifier to maintain the mean peak-to-average ratio substantially equal to the desired peak-to-average ratio.

12. The power amplifying circuit as in claim 10 wherein the mean peak-to-average ratio comprises a ratio of an average of the peak levels to the average power over a predetermined period of time.

13. The power amplifying circuit as in claim 12 wherein the peak-to-average detector calculates the mean peak-to-average ratio.

14. The power amplifying circuit as in claim 12 wherein the controller calculates the mean peak-to-average ratio.

15. The power amplifying circuit as in claim 10 further comprising a variable gain circuit coupled to an input of the power amplifier, wherein the controller controls a gain of the variable gain circuit responsive to the indication of the average power to cause the average power to substantially equal a desired average output power.

16. The power amplifying circuit as in claim 10 further comprising a voltage control circuit coupled between the controller and the power amplifier, wherein the controller produces a control signal responsive to the indication of the peak levels and the average power, the voltage control circuit processing the control signal to produce the supply voltage.

17. The power amplifying circuit as in claim 16 wherein the voltage control circuit comprises one of a linear voltage regulator and a switching voltage regulator.

18. The power amplifying circuit as in claim 10 wherein the input signal and the amplified signal have an amplitude modulation envelope resulting from a linear modulation scheme selected from the group consisting of phase-shift keying (PSK) and quadrature amplitude modulation (QAM).

19. A method of amplifying a radio frequency (RF) signal, the method comprising:

amplifying the RF signal with a power amplifier to produce an amplified signal;

detecting an average output level and peak levels of the amplified signal;

calculating a peak-to-average ratio of the amplified signal; and

lowering a supply voltage to the power amplifier when the peak-to-average ratio increases above a predetermined level, or

elevating the supply voltage to the power amplifier when the peak-to-average ratio decreases below a predetermined level.

20. The method as in claim 19 further comprising adjusting an average amplitude of the RF signal to produce the amplified signal with a desired average power.

21. The method as in claim 19 wherein the peak-to-average ratio comprises a maximum peak-to-average ratio over a period of time or over a number of peak levels.

22. The method as in claim 19 wherein the peak-to-average ratio comprises a mean peak-to-average ratio over a period of time or over a number of peak levels.

23. A power amplifying circuit comprising:

a power amplifier for amplifying an input signal to produce an amplified signal;

a peak-to-average detector coupled to an output of the power amplifier, the peak-to-average detector to detect a peak level of the amplified signal and an average level of the amplified signal and to provide an indication of a difference between the peak level and the average level; and

a controller coupled to the power amplifier and the peak-to-average detector, the controller for adjusting a supply voltage to the power amplifier responsive to the indication of the difference between the peak level and the average level to cause the supply voltage to lower as the difference between the peak level and the average level increases above a predetermined level and to cause the supply voltage to elevate as the difference between the peak level and the average level decreases below the predetermined level.

24. The power amplifying circuit as in claim 23 wherein the controller causes the power amplifier to maintain the difference between the peak level and the average level substantially equal to a predetermined level.