OUTPHASING TRANSMITTER SYSTEMS AND METHODS

• US 20170033743A1
• Filed: 07/29/2015
• Published: 02/02/2017
• Est. Priority Date: 07/29/2015
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: MIRZAEI, Alex Ahmad, DARABI, Hooman
• Granted Patent: US 9,742,367 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H03F 1/0294 using vector summing of two or more constant amplitude phase-modulated signals
• CPC Class Codes: H03F 1/565 using inductive elements
• CPC Class Codes: H03F 2200/339 Pulse amplitude modulation being used in an amplifying circuit
• CPC Class Codes: H03F 2200/351 Pulse width modulation being used in an amplifying circuit
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 3/193 with field-effect devices H03F3/195 takes precedence
• CPC Class Codes: H03F 3/217 Class D power amplifiers; Switching amplifiers
• CPC Class Codes: H03F 3/2171 with field-effect devices H03F3/2173 - H03F3/2178 take precedence
• CPC Class Codes: H03F 3/245 with semiconductor devices only

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.

Claims

1. A transmitter front-end, comprising:

a modulator configured to produce a first constant-envelope rectangular wave signal of amplitude A₀ and phase (θ

−

φ

) and a second constant-envelope rectangular wave signal of amplitude A₀ and phase (θ

+φ

), where θ

is a modulation angle and φ

is an outphasing angle; and

an AND-core 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.

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

3. The transmitter front-end of claim 1, wherein the AND-core power amplifier comprises:

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 the 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 the gates of the second set of Iwo series transistors are respectively coupled to the complement of the first constant-envelope rectangular wave signal and the 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 A₀ and phase (θ

−

φ

) and a second constant-envelope rectangular wave signal of amplitude A₀ and phase (θ

+φ

), where θ

is a modulation angle and φ

is an outphasing angle;

an AND-core 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; 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 AND-core power amplifier is a class-D power amplifier.

11. The transmitter front-end of claim 9, wherein the AND-core power amplifier comprises:

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 the 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 the gates of the second set of two series transistors are respectively coupled to the complement of the first constant-envelope rectangular wave signal and the 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 A₀ 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 A₀ and phase (θ

+φ

); and

amplifying, using a class-D 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.

18. The method of claim 17, further comprising:

sweeping φ

over a range of values; and

measuring amplitude A and phase Ψ

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

.