IP Library › Granted Patent US 8,169,261

Granted Patent B2

US 8,169,261 · App. 12/360,727 · Granted May 1, 2012

High efficiency amplification

Assignee: Nujira Limited

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Quick Facts

Patent No.: US 8,169,261
App. No.: 12/360,727
Granted: May 1, 2012
Kind: B2

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Abstract

A radio frequency amplification stage comprising: an amplifier for receiving an input signal to be amplified and a power supply voltage; and a power supply voltage stage for supplying said power supply voltage, comprising: means for providing a reference signal representing the envelope of the input signal; means for selecting one of a plurality of supply voltage levels in dependence on the reference signal; and means for generating an adjusted selected power supply voltage, comprising an ac amplifier for amplifying a difference between the reference signal and one of the selected supply voltage level or the adjusted selected supply voltage level, and a summer for summing the amplified difference with the selected supply voltage to thereby generate the adjusted supply voltage.

Claims (90)

1. A power supply stage, comprising:

a. reference means for providing a reference signal representing a desired power supply voltage;

b. selection means for selecting one of a plurality of power supply voltages in dependence on the reference signal;

c. adjusting means adapted to generate an adjusted selected power supply voltage tracking the reference signal in dependence on the selected power supply voltage and the reference signal, wherein the adjusting means includes an AC amplifier, wherein the AC amplifier is connected to amplify the difference between the reference signal and a representation of the selected power supply voltage, and wherein the adjusting means includes means for summing the amplified difference with the selected supply voltage.

2. A power supply according to claim 1 , wherein the selected power supply voltage has a minimum absolute difference between said power supply voltage and the reference signal level.

3. A power supply stage according to claim 1 wherein the AC amplifier is connected to amplify the difference between the reference signal and a representation of the selected power supply voltage.

4. A power supply stage according to claim 1 , wherein the representation of the selected power supply voltage is the power supply voltage itself.

5. A power supply stage according to claim 1 wherein the representation of the selected power supply voltage is the adjusted selected power supply voltage.

6. A power supply stage according to claim 1 wherein the adjusted selected supply voltage is the output of the power supply stage.

7. A power supply stage according to claim 1 wherein the adjusting means further includes a high frequency amplifier.

8. A power supply stage according to claim 7 wherein the high frequency amplifier is connected to amplify the difference between the reference signal and a representation of the adjusted power supply voltage.

9. A power supply stage according to claim 1 in which there is provided a delay element for delaying the reference signal.

10. A power supply stage according to claim 1 wherein the power supply stage is for an amplifier, the reference signal representing the envelope of an input signal of said amplifier.

11. A power supply stage according to claim 10 in which there is provided a delay element for compensating for differences in delays between the signal amplifier and power supply control input.

12. A power supply stage, comprising:

a. reference means for providing a reference signal representing a desired power supply voltage;

b. selection means for selecting one of a plurality of power supply voltages in dependence on the reference signal;

c. adjusting means adapted to generate an adjusted selected power supply voltage tracking the reference signal in dependence on the selected power supply voltage and the reference signal, wherein the adjusting means includes an AC amplifier, wherein the adjusting means further includes a high frequency amplifier, wherein the high frequency amplifier is connected to amplify the difference between the reference signal and a representation of the adjusted power supply voltage, and wherein the adjusting means includes means for summing the amplified difference with the adjusted supply voltage to generate a further adjusted supply voltage.

13. A power supply stage according to claim 12 wherein the representation of the adjusted supply voltage is the adjusted supply voltage itself.

14. A power supply stage according to claim 12 wherein the representation of the adjusted supply voltage is the further adjusted supply voltage.

15. A power supply stage according to claim 12 wherein the further adjusted supply voltage forms the output of the power supply stage.

16. A power supply stage, comprising:

a. reference means for providing a reference signal representing a desired power supply voltage;

b. selection means for selecting one of a plurality of power supply voltages in dependence on the reference signal;

c. adjusting means adapted to generate an adjusted selected power supply voltage tracking the reference signal in dependence on the selected power supply voltage and the reference signal wherein there is further provided an interpolation means at the input to the adjusting means such that the selected power supply voltage is interpolated.

17. A power supply stage according to claim 16 wherein the interpolation means comprises an inductor-capacitor arrangement.

18. A power supply stage, comprising:

a. reference means for providing a reference signal representing a desired power supply voltage;

b. selection means for selecting one of a plurality of power supply voltages in dependence on the reference signal;

19. A power supply stage according to claim 18 wherein the means for DC clamping is responsive to detection of the reference signal being less than the adjusted supply voltage.

20. A radio frequency amplification stage comprising:

a. an amplifier for receiving an input signal to be amplified and a power supply voltage; and

b. a power supply voltage stage for supplying said power supply voltage, comprising:

i. means for providing a reference signal representing a desired power supply voltage corresponding to the envelope of the input signal;

ii. means for selecting one of a plurality of supply voltage levels in dependence on the reference signal; and

iii. means for generating an adjusted selected power supply voltage, comprising an AC amplifier for amplifying a difference between the reference signal and one of the selected supply voltage level or the adjusted selected supply voltage level, and a summer for summing the amplified difference with the selected supply voltage to thereby generate the adjusted supply voltage.

21. A radio frequency amplification stage according to claim 20 in which the means for generating an adjusted selected supply voltage further generates a further adjusted supply voltage and further comprises an RF amplifier for amplifying a difference between the reference signal and one of the adjusted supply voltage or the further adjusted supply voltage, and a summer for summing such amplified difference with the adjusted supply voltage to thereby generate the further adjusted supply voltage.

22. A radio frequency amplification stage according to claim 20 wherein one of the adjusted supply voltage or further adjusted supply voltage forms the supply voltage to the amplifier.

23. A method of controlling a power supply stage, comprising:

a. providing a reference signal representing a desired power supply voltage;

b. selecting one of a plurality of power supply voltages in dependence on the reference signal;

c. generating an adjusted selected power supply voltage tracking the reference signal in dependence on the selected power supply voltage and the reference signal, wherein the difference between the reference signal and a representation of the selected power supply voltage is AC amplified, and wherein the difference between the reference signal and a representation of the selected power supply voltage is AC amplified, and wherein the amplified difference is summed with the selected supply voltage to form the adjusted supply voltage.

24. A method according to claim 23 wherein the reference signal represents the envelope of an input signal to an amplifier, the power supply stage providing a power supply to said amplifier.

25. A method according to claim 23 wherein the difference between the reference signal and a representation of the adjusted power supply voltage is RF amplified.

26. A method according to claim 25 wherein the amplified difference is summed with the adjusted supply voltage to form a further adjusted supply voltage.

27. A method according to claim 23 , further comprising providing means for removing a dc component in the AC amplification step.

28. A method of controlling a power supply stage, comprising:

a. providing a reference signal representing a desired power supply voltage;

b. selecting one of a plurality of power supply voltages in dependence on the reference signal;

c. generating an adjusted selected power supply voltage tracking the reference signal in dependence on the selected power supply voltage and the reference signal, further comprising an interpolating step prior to said step of generating an adjusted supply voltage.

29. A power supply stage, comprising: