APPARATUS AND METHODS FOR POWER AMPLIFIERS WITH AN INJECTION-LOCKED OSCILLATOR DRIVER STAGE

• US 20170324388A1
• Filed: 05/02/2017
• Published: 11/09/2017
• Est. Priority Date: 05/05/2016
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Soliman, Yasser Khairat
• Granted Patent: US 10,171,053 B2
• Time in Patent Office: Days
• CPC Class Codes: H03B 2200/0074 Locking of an oscillator by injecting an input signal directly into the oscillator
• CPC Class Codes: H03B 5/08 with frequency-determining element comprising lumped inductance and capacitance
• CPC Class Codes: H03B 5/1215 the current source or degeneration circuit being in common to both transistors of the pair, e.g. a cross-coupled long-tailed pair
• CPC Class Codes: H03B 9/12 using solid state devices, e.g. Gunn-effect devices
• CPC Class Codes: H03F 1/0227 using supply converters
• CPC Class Codes: H03F 2200/411 the output amplifying stage of an amplifier comprising two power stages
• CPC Class Codes: H03F 2200/516 Some amplifier stages of an amplifier use supply voltages of different value
• CPC Class Codes: H03F 2203/7239 the gated amplifier being switched on or off by putting into parallel or not, by choosing between amplifiers and shunting lines by one or more switch(es)
• CPC Class Codes: H03F 3/193 with field-effect devices H03F3/195 takes precedence
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/72 Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal
• CPC Class Codes: H03G 3/20 Automatic control H03G3/005 takes precedence; combined with volume compression or expansion H03G7/00
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04

Abstract

Apparatus and methods for power amplifiers with an injection-locked oscillator driver stage are provided herein. In certain configurations, a multi-mode power amplifier includes a driver stage implemented using an injection-locked oscillator and an output stage having an adjustable supply voltage that changes based on a mode of the multi-mode power amplifier. By implementing the multi-mode power amplifier in this manner, the multi-mode power amplifier exhibits excellent efficiency, including when the voltage level of the adjustable supply voltage is relatively low.

Claims

1. A multi-mode power amplifier comprising:

a driver stage including an injection-locked oscillator configured to receive a radio frequency input signal and to generate an injection-locked radio frequency signal;

an output stage configured to amplify the injection-locked radio frequency signal to generate a radio frequency output signal, the output stage configured to receive power from an adjustable supply voltage; and

a supply control circuit configured to control a voltage level of the adjustable supply voltage based on a mode of the multi-mode power amplifier.

2. The multi-mode power amplifier of claim 1 wherein the injection-locked oscillator includes an output balun configured to provide a differential to singled-ended signal conversion.

3. The multi-mode power amplifier of claim 1 wherein the driver stage is powered by a substantially fixed supply voltage.

4. The multi-mode power amplifier of claim 3 wherein the mode of the multi-mode power amplifier is selectable between two or more power modes including a high power mode in which the adjustable supply voltage is greater than the substantially fixed supply voltage and a low power mode in which the adjustable supply voltage is less than the substantially fixed supply voltage.

5. The multi-mode power amplifier of claim 1 wherein the radio frequency input signal is a modulated signal having a substantially constant signal envelope.

6. The multi-mode power amplifier of claim 1 wherein the radio frequency input signal is a single-ended input signal, and the injection-locked oscillator includes an input transformer configured to convert the single-ended input signal to a differential input signal.

7. The multi-mode power amplifier of claim 1 wherein the injection-locked oscillator includes a negative transconductance circuit electrically connected to an inductor-capacitor tank, the negative transconductance circuit configured to provide energy to the inductor-capacitor tank to maintain oscillations.

8. The multi-mode power amplifier of claim 7 wherein the negative transconductance circuit includes a pair of cross-coupled field-effect transistors.

9. The multi-mode power amplifier of claim 7 wherein the injection-locked oscillator further includes a signal injecting circuit configured to provide signal injection to the inductor-capacitor tank based on the radio frequency input signal.

10. A method of radio frequency signal amplification, the method comprising:

generating an injection-locked radio frequency signal from a radio frequency input signal using an injection-locked oscillator of a multi-mode power amplifier;

amplifying the injection-locked radio frequency signal using an output stage of the multi-mode power amplifier;

powering the output stage using an adjustable supply voltage; and

controlling a voltage level of the adjustable supply voltage based on a mode of the multi-mode power amplifier using a supply control circuit.

11. The method of claim 10 further comprising providing a differential to singled-ended signal conversion at an output of the driver stage using an output balun.

12. The method of claim 10 further comprising powering the driver stage using a substantially fixed supply voltage.

13. The method of claim 10 further comprising providing a modulated signal having a substantially constant signal envelope to an input of the driver stage.

14. The method of claim 10 further comprising injection locking an inductor-capacitor tank of the injection-locked oscillator to the radio frequency input signal.

15. The method of claim 14 further comprising providing energy to the inductor-capacitor tank to maintain oscillations using a negative transconductance circuit.

16. A packaged module comprising:

a package substrate; and

a semiconductor die attached to the package substrate, the semiconductor die including a multi-mode power amplifier including a driver stage including an injection-locked oscillator configured to receive a radio frequency input signal and to generate an injection-locked radio frequency signal, and an output stage configured to amplify the injection-locked radio frequency signal to generate a radio frequency output signal, the output stage configured to receive power from an adjustable supply voltage having a voltage level that changes based on a mode of the multi-mode power amplifier.

17. The packaged module of claim 16 wherein the semiconductor die further includes a low noise amplifier and a switch electrically connected to the low noise amplifier and to the multi-mode power amplifier.

18. The packaged module of claim 16 wherein the injection-locked oscillator includes a negative transconductance circuit electrically connected to an inductor-capacitor tank, the negative transconductance circuit configured to provide energy to the inductor-capacitor tank to maintain oscillations.

19. The packaged module of claim 18 wherein the injection-locked oscillator further includes a signal injecting circuit configured to provide signal injection to the inductor-capacitor tank based on the radio frequency input signal.

20. The packaged module of claim 16 wherein the semiconductor die is a silicon-on-insulator die.