Biasing of cascode power amplifiers for multiple power supply domains

Patent metadata

Field	Value
Publication number	US-12316286-B2
Application number	US-202217807299-A
Country	US
Kind code	B2
Filing date	Jun 16, 2022
Priority date	Jul 9, 2021
Publication date	May 27, 2025
Grant date	May 27, 2025

Abstract

Bias schemes for cascode power amplifiers are disclosed. In certain embodiments, a power amplifier system includes a cascode power amplifier powered by a first supply voltage and that amplifies a radio frequency input signal, and a bias circuit including a voltage regulator that generates a regulated voltage and is powered by the first supply voltage. The bias circuit further includes a bias voltage generation circuit that receives the regulated voltage and generates at least one cascode bias voltage for the cascode power amplifier, a switch that gates a second supply voltage to generate a gated supply voltage, a bias current generation circuit that controls a bias current of the cascode power amplifier and is powered by the gated supply voltage, and a gating circuit that controls the switch based on the regulated voltage and the second supply voltage.

First claim

What is claimed is:

1. A power amplifier system comprising:
a cascode power amplifier powered by a first supply voltage and configured to amplify a radio frequency input signal; and
a bias circuit including a voltage regulator configured to generate a regulated voltage and powered by the first supply voltage, a bias voltage generation circuit configured to receive the regulated voltage and to generate at least one cascode bias voltage for the cascode power amplifier, a switch configured to gate a second supply voltage to generate a gated supply voltage, a bias current generation circuit configured to control a bias current of the cascode power amplifier and powered by the gated supply voltage, and a gating circuit configured to control the switch based on the regulated voltage and the second supply voltage.

2. The power amplifier system of claim 1 wherein the cascode power amplifier includes a gain transistor and a first cascode transistor, the at least one cascode bias voltage including a first cascode bias voltage configured to bias the first cascode transistor.

3. The power amplifier system of claim 2 wherein the first cascode transistor is a field-effect transistor having a gate biased by the first cascode bias voltage and a source biased by the bias current.

4. The power amplifier system of claim 2 wherein the cascode power amplifier further includes a second cascode transistor, the at least one cascode bias voltage including a second cascode bias voltage configured to bias the second cascode transistor.

5. The power amplifier system of claim 1 wherein the bias circuit is configured to bias the cascode power amplifier across two or more voltage levels of the first supply voltage, the two or more voltage levels associated with two or more power supply domains.

6. The power amplifier system of claim 1 wherein the bias circuit includes a cascode control circuit for setting a voltage level of the at least one cascode bias voltage generated by the bias voltage generation circuit, and an interface circuit powered by a third supply voltage and configured to generate a bias current control signal for the bias current generation circuit and a bias voltage control signal for the cascode control circuit.

7. The power amplifier system of claim 6 wherein the gating circuit is further operable to control gating of the switch based on a voltage level of the third supply voltage.

8. The power amplifier system of claim 6 wherein the gating circuit is further configured to generate a power supply status signal for the cascode control circuit, the power supply status signal indicating when the gated supply voltage is active.

9. The power amplifier system of claim 6 wherein the cascode control circuit includes a level shifter configured to level shift the bias voltage control signal to a power domain of the first supply voltage.

10. A method of power amplifier biasing, the method comprising:
amplifying a radio frequency input signal using a cascode power amplifier that receives power from a first supply voltage;
generating a regulated voltage using a voltage regulator that receives power from the first supply voltage;
generating at least one cascode bias voltage for the cascode power amplifier based on the regulated voltage using a bias voltage generation circuit;
gating a second supply voltage to generate a gated supply voltage using a switch, including controlling the switch based on the regulated voltage and the second supply voltage; and
controlling a bias current of the cascode power amplifier using a bias current generation circuit that receives power from the gated supply voltage.

11. The method of claim 10 further comprising setting a voltage level of the at least one cascode bias voltage using a cascode control circuit, and generating a bias current control signal for the bias current generation circuit and a bias voltage control signal for the cascode control circuit using an interface circuit that receives power from a third supply voltage.

12. The method of claim 11 further comprising controlling gating of the switch based on a voltage level of the third supply voltage.

13. The method of claim 11 further comprising generating a power supply status signal for the cascode control circuit, the power supply status signal indicating when the gated supply voltage is active.

14. A mobile device comprising:
a transceiver configured to generate a radio frequency input signal; and
a front end system including a cascode power amplifier powered by a first supply voltage and configured to amplify the radio frequency input signal, and a bias circuit including a voltage regulator configured to generate a regulated voltage and powered by the first supply voltage, a bias voltage generation circuit configured to receive the regulated voltage and to generate at least one cascode bias voltage for the cascode power amplifier, a switch configured to gate a second supply voltage to generate a gated supply voltage, a bias current generation circuit configured to control a bias current of the cascode power amplifier and powered by the gated supply voltage, and a gating circuit configured to control the switch based on the regulated voltage and the second supply voltage.

15. The mobile device of claim 14 wherein the bias circuit is configured to bias the cascode power amplifier across two or more voltage levels of the first supply voltage, the two or more voltage levels associated with two or more power supply domains.

16. The mobile device of claim 14 wherein the bias circuit includes a cascode control circuit for setting a voltage level of the at least one cascode bias voltage generated by the bias voltage generation circuit, and an interface circuit powered by a third supply voltage and configured to generate a bias current control signal for the bias current generation circuit and a bias voltage control signal for the cascode control circuit.

17. The mobile device of claim 16 wherein the gating circuit is further operable to control gating of the switch based on a voltage level of the third supply voltage.

18. The mobile device of claim 16 wherein the gating circuit is further configured to generate a power supply status signal for the cascode control circuit, the power supply status signal indicating when the gated supply voltage is active.

19. The mobile device of claim 16 wherein the cascode control circuit includes a level shifter configured to level shift the bias voltage control signal to a power domain of the first supply voltage.

20. The mobile device of claim 14 further comprising an antenna configured to wirelessly transmit an amplified radio frequency signal generated by the cascode power amplifier.

Assignees

• Skyworks Solutions Inc

Inventors

• LIANG Bang Li
• Blin Guillaume Alexandre
• Obkircher Thomas

Classifications

• H03F1/02

  Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation · CPC title

• H04B1/40 Primary

  Circuits · CPC title

• H03F2200/451

  the amplifier being a radio frequency amplifier · CPC title

• H03F2200/61

  the cascode amplifier has more than one common gate stage · CPC title

• H03F1/0261

  with control of the polarisation voltage or current, e.g. gliding Class A · CPC title