Reconfigurable output balun for wideband push-pull power amplifiers

Patent metadata

Field	Value
Publication number	US-12316355-B2
Application number	US-202217811659-A
Country	US
Kind code	B2
Filing date	Jul 11, 2022
Priority date	Jul 26, 2021
Publication date	May 27, 2025
Grant date	May 27, 2025

Abstract

Reconfigurable output baluns for wideband push-pull amplifiers are disclosed. In certain embodiments, a mobile device includes a transceiver that generates a first radio frequency signal of a first frequency band and a second radio frequency signal of a second frequency band, and a front-end system including a push-pull power amplifier that selectively amplifies one of the first radio frequency signal or the second radio frequency signal based on a band control signal. The push-pull power amplifier includes an input balun, an output balun, and a pair of amplifiers coupled between the input balun and the output balun. The band control signal is operable to control an impedance of the output balun.

First claim

What is claimed is:

1. A push-pull power amplifier comprising:
an input selection circuit configured to output a selected radio frequency signal based on a band control signal, the selected radio frequency signal chosen from one of a first radio frequency signal of a first frequency band or a second radio frequency signal of a second frequency band;
an input balun;
a pair of amplifiers including a pair of inputs connected to the input balun and a pair of outputs, the pair of amplifiers operable to amplify the selected radio frequency signal; and
an output balun connected to the pair of outputs of the pair of amplifiers, the band control signal operable to control an impedance of the output balun.

2. The push-pull power amplifier of claim 1 wherein the output balun includes a first coupled line connected between a first output of the pair of outputs and a second output of the pair of outputs, a second coupled line electromagnetically coupled to the first coupled line, and at least one controllable capacitor controlled by the band control signal.

3. The push-pull power amplifier of claim 2 wherein the at least one controllable capacitor includes a first controllable capacitor coupled to a center tap of the first coupled line.

4. The push-pull power amplifier of claim 2 wherein the at least one controllable capacitor includes a first controllable capacitor coupled to one end of the second coupled line, the other end of the second coupled line configured to generate an amplified radio frequency signal.

5. The push-pull power amplifier of claim 2 wherein the first amplifier includes a first bipolar transistor and the second amplifier includes a second bipolar transistor, the first coupled line connected between a collector of the first bipolar transistor and a collector of the second bipolar transistor.

6. The push-pull power amplifier of claim 2 wherein the at least one controllable capacitor includes a first controllable capacitor including a first fixed capacitor in parallel with a switched capacitor.

7. The push-pull power amplifier of claim 6 wherein the switched capacitor incudes a plurality of field-effect transistors in series with a second fixed capacitor, the plurality of field-effect transistors having a gate voltage controlled by the band control signal.

8. A method of amplification, the method comprising:
outputting a selected radio frequency signal based on a band control signal using an input selection circuit of a push-pull power amplifier, the selected radio frequency signal chosen from one of a first radio frequency signal of a first frequency band or a second radio frequency signal of a second frequency band;
amplifying the selected radio frequency signal using a pair of amplifiers of the push-pull power amplifier, the pair of amplifiers including a pair of inputs connected to an input balun of the push-pull power amplifier; and
controlling an impedance of an output balun of the push-pull power amplifier using the band control signal, the output balun connected to a pair of outputs of the pair of amplifiers.

9. The method of claim 8 wherein the output balun includes a first coupled line connected between a first output of the pair of outputs and a second output of the pair of outputs, a second coupled line electromagnetically coupled to the first coupled line, and at least one controllable capacitor, the method further comprising controlling the at least one controllable capacitor using the band control signal.

10. The method of claim 9 wherein the at least one controllable capacitor includes a first controllable capacitor coupled to a center tap of the first coupled line.

11. The method of claim 9 wherein the at least one controllable capacitor includes a first controllable capacitor coupled to one end of the second coupled line, the other end of the second coupled line configured to generate an amplified radio frequency signal.

12. The method of claim 9 wherein the first amplifier includes a first bipolar transistor and the second amplifier includes a second bipolar transistor, the first coupled line connected between a collector of the first bipolar transistor and a collector of the second bipolar transistor.

13. The method of claim 9 wherein the at least one controllable capacitor includes a first controllable capacitor including a first fixed capacitor in parallel with a switched capacitor.

14. A mobile device comprising:
a front-end system including a push-pull power amplifier that includes an input selection circuit configured to output a selected radio frequency signal based on a band control signal, the selected radio frequency signal chosen from one of a first radio frequency signal of a first frequency band or a second radio frequency signal of a second frequency band, the push-pull power amplifier further including an input balun and a pair of amplifiers including a pair of inputs connected to the input balun, the pair of amplifiers operable to amplify the selected radio frequency signal, the push-pull power amplifier further including an output balun connected to a pair of outputs of the pair of amplifiers, the band control signal operable to control an impedance of the output balun; and
an antenna configured to transmit an amplified radio frequency signal outputted by the push-pull power amplifier.

15. The mobile device of claim 14 wherein the output balun includes a first coupled line connected between a first output of the pair of outputs and a second output of the pair of outputs, a second coupled line electromagnetically coupled to the first coupled line, and at least one controllable capacitor controlled by the band control signal.

16. The mobile device of claim 15 wherein the at least one controllable capacitor includes a first controllable capacitor coupled to a center tap of the first coupled line.

17. The mobile device of claim 15 wherein the at least one controllable capacitor includes a first controllable capacitor coupled to one end of the second coupled line, the other end of the second coupled line configured to generate the amplified radio frequency signal.

18. The mobile device of claim 15 wherein the first amplifier includes a first bipolar transistor and the second amplifier includes a second bipolar transistor, the first coupled line connected between a collector of the first bipolar transistor and a collector of the second bipolar transistor.

19. The mobile device of claim 15 wherein the at least one controllable capacitor includes a first controllable capacitor including a first fixed capacitor in parallel with a switched capacitor.

20. The mobile device of claim 19 wherein the switched capacitor incudes a plurality of field-effect transistors in series with a second fixed capacitor, the plurality of field-effect transistors having a gate voltage controlled by the band control signal.

Assignees

• Skyworks Solutions Inc

Inventors

• Datta Kunal
• Wu Hemin
• Zhao Shanshan
• Ali Sheikh Nijam
• Feng Jinghang

Classifications

• H03F3/265

  with field-effect transistors only · CPC title

• H04B2001/0416

  having gain or transmission power control · CPC title

• H04B2001/0433

  with linearisation using feedback · CPC title

• H03F3/211

  using a combination of several amplifiers (H03F3/60 takes precedence) · CPC title

• H03F2200/516

  Some amplifier stages of an amplifier use supply voltages of different value · CPC title