Outphasing transmitter systems and methods

Patent metadata

Field	Value
Publication number	US-9742367-B2
Application number	US-201514812579-A
Country	US
Kind code	B2
Filing date	Jul 29, 2015
Priority date	Jul 29, 2015
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

The present disclosure is directed to a system and method for performing the outphasing technique without using a combiner at the output of two power amplifiers to reduce loss and distortions.

First claim

What is claimed is:

1. A transmitter front-end, comprising:
a modulator configured to produce a first constant-envelope rectangular wave signal of amplitude A 0 and phase (θ−φ) and a second constant-envelope rectangular wave signal of amplitude A 0 and phase (θ+φ), where θ is a modulation angle and φ is an outphasing angle; and
a power amplifier configured to amplify a logical conjunction of the first constant-envelope rectangular wave signal and the second constant-envelope rectangular wave signal to provide an output signal, wherein the power amplifier comprises at least two series coupled switches configured to provide the logical conjunction of the first constant-envelope rectangular wave signal and the second constant-envelope rectangular wave signal.

2. The transmitter front-end of claim 1 , wherein the power amplifier is a class-D power amplifier.

3. The transmitter front-end of claim 1 , wherein the at least two series coupled switches comprise:
a first set of two series transistors coupled between ground and a first end of a primary winding of a balun; and
a second set of two series transistors coupled between ground and a second end of the primary winding of the balun.

4. The transmitter front-end of claim 3 , wherein gates of the first set of two series transistors are respectively coupled to the first constant-envelope rectangular wave signal and the second constant-envelope rectangular wave signal.

5. The transmitter front-end of claim 3 , wherein gates of the second set of two series transistors are respectively coupled to a complement of the first constant-envelope rectangular wave signal and a complement of the second constant-envelope rectangular wave signal.

6. The transmitter front-end of claim 1 , further comprising:
a calibration circuit configured to sweep φ over a range of values and measure amplitude A and phase Ψ of the output signal over the range of values for φ.

7. The transmitter front-end of claim 6 , wherein the calibration circuit is further configured to subtract, for a given value of φ, a value proportional to the measured value of Ψ at the given value of φ from the first constant-envelope rectangular wave signal and the second constant-envelope rectangular wave signal.

8. The transmitter front-end of claim 6 , wherein the calibration circuit is further configured to map φ to φ′ based on the measured value of A at φ′ corresponding to a desired value of A at φ.

9. A transmitter front-end, comprising:
a modulator configured to produce a first constant-envelope rectangular wave signal of amplitude A 0 and phase (θ−φ) and a second constant-envelope rectangular wave signal of amplitude A 0 and phase (θ+φ), where θ is a modulation angle and φ is an outphasing angle;
a power amplifier configured to amplify a logical conjunction of the first constant-envelope rectangular wave signal and the second constant-envelope rectangular wave signal to provide an output signal, wherein the power amplifier comprises at least two series coupled switches configured to provide the logical conjunction of the first constant-envelope rectangular wave signal and the second constant-envelope rectangular wave signal; and
a calibration circuit configured to calibrate an amplitude A and phase Ψ of the output signal by adjusting φ.

10. The transmitter front-end of claim 9 , wherein the power amplifier is a class-D power amplifier.

11. The transmitter front-end of claim 9 , wherein the at least two series coupled switches comprise:
a first set of two series transistors coupled between ground and a first end of a primary winding of a balun; and
a second set of two series transistors coupled between ground and a second end of the primary winding of the balun.

12. The transmitter front-end of claim 11 , wherein gates of the first set of two series transistors are respectively coupled to the first constant-envelope rectangular wave signal and the second constant-envelope rectangular wave signal.

13. The transmitter front-end of claim 11 , wherein gates of the second set of two series transistors are respectively coupled to a complement of the first constant-envelope rectangular wave signal and a complement of the second constant-envelope rectangular wave signal.

14. The transmitter front-end of claim 11 , wherein the calibration circuit is further configured to sweep φ over a range of values and measure A and Ψ over the range of values for φ.

15. The transmitter front-end of claim 14 , wherein the calibration circuit is further configured to subtract, for a given value of φ, a value proportional to the measured value of Ψ at the given value of φ from the first constant-envelope rectangular wave signal and the second constant-envelope rectangular wave signal.

16. The transmitter front-end of claim 14 , wherein the calibration circuit is further configured to map φ to φ′ based on the measured value of A at φ′ corresponding to a desired value of A at φ.

17. A method, comprising:
producing a first constant-envelope rectangular wave signal of amplitude A 0 and phase (θ−φ), where θ is a modulation angle and φ is an outphasing angle;
producing a second constant-envelope rectangular wave signal of amplitude A 0 and phase (θ+φ); and
amplifying, using a power amplifier, a logical conjunction of the first constant-envelope rectangular wave signal and the second constant-envelope rectangular wave signal to provide an output signal,
wherein the logical conjunction of the first constant-envelope rectangular wave signal and the second constant-envelope rectangular wave signal is provided by at least two series coupled switches of the power amplifier.

18. The method of claim 17 , further comprising:
sweeping φ over a range of values; and
measuring amplitude A and phase Ψ of the output signal over the range of values for φ.

19. The method of claim 18 , further comprising:
subtracting, for a given value of φ, a value proportional to the measured value of Ψ at the given value of φ from the first constant-envelope rectangular wave signal and the second constant-envelope rectangular wave signal.

20. The method of claim 18 , further comprising:
mapping φ to φ′ based on the measured value of A at φ′ corresponding to a desired value of A at φ.

Assignees

• Avago Technologies General Ip

Inventors

• Mirzaei Alex Ahmad
• Darabi Hooman

Classifications

• H03F2200/339

  Pulse amplitude modulation being used in an amplifying circuit · CPC title

• H03F2200/451

  the amplifier being a radio frequency amplifier · CPC title

• H03F3/217 Primary

  Class D power amplifiers; Switching amplifiers · CPC title

• H03F3/245

  with semiconductor devices only · CPC title

• H03F3/193

  with field-effect devices (H03F3/195 takes precedence) · CPC title