Doherty amplifier
View Patent ↗A multistage linear power amplifier receiving an input signal. The multistage linear power amplifier comprises a plurality of Class-AB amplifiers connected in a cascade configuration. The plurality of Class-AB amplifiers amplifies the input signal to generate an amplified input signal. At least one of the plurality of Class-AB amplifiers is biased such that the multistage linear power amplifier emulates a Class-C amplifier.
1. A multistage linear power amplifier receiving an input signal, the multistage linear power amplifier comprising:
a plurality of Class-AB amplifiers connected in a cascade configuration, the plurality of Class-AB amplifiers amplifying the input signal to generate an amplified input signal, and at least one of the plurality of Class-AB amplifiers is biased such that the multistage linear power amplifier emulates the behavior of a Class-C amplifier.
2. The multistage linear power amplifier of claim 1 , wherein the plurality of Class-AB amplifiers comprises a first Class-AB amplifier, a second Class-AB amplifier, and a third Class-AB amplifier.
3. The multistage linear power amplifier of claim 2 , wherein the first Class-AB amplifier is configured as an input stage of the multistage linear power amplifier.
4. The multistage linear power amplifier of claim 2 , wherein the second Class-AB amplifier is configured as a driver stage of the multistage linear power amplifier.
5. The multistage linear power amplifier of claim 2 , wherein the third Class-AB amplifier is configured as an output stage of the multistage linear power amplifier.
6. The multistage linear power amplifier of claim 1 , wherein the plurality of Class-AB amplifiers operates as a peaking amplifier to amplify peaks in the input signal.
7. A Doherty amplifier comprising:
a first multistage amplifier receiving an input signal, the first multistage amplifier having a first plurality of Class-AB amplifiers, connected in a cascade configuration, wherein the first plurality of Class-AB amplifiers amplifies the input signal; and
a second multistage amplifier receiving a phase-shifted input signal, the second multistage amplifier having a second plurality of Class-AB amplifiers, connected in the cascade configuration, the second plurality of Class-AB amplifiers amplifying the phase-shifted input signal, and at least one of the second plurality of Class-AB amplifiers is biased such that the second multistage amplifier emulates the behavior of a Class-C amplifier.
8. The Doherty amplifier of claim 7 , further comprising a signal combiner, wherein the signal combiner combines the amplified input signal from the first multistage amplifier and the amplified phase-shifted input signal from the second multistage amplifier.
9. The Doherty amplifier of claim 7 , wherein the first multistage amplifier operates as a main amplifier to amplify the input signal.
10. The Doherty amplifier of claim 7 , wherein the second multistage amplifier operates as a peaking amplifier to amplify peaks in the phase-shifted input signal.
11. A Doherty amplifier comprising:
a signal splitter receiving an input signal, the signal splitter spliting the input signal to generate a first input signal and a second input signal;
a main amplifier including a first plurality of Class-AB amplifiers connected in a cascade configuration, the main amplifier amplifying the first input signal;
a peaking amplifier including a second plurality of Class-AB amplifiers connected in the cascade configuration, at least one of the second plurality of Class-AB amplifiers being biased such that the peaking amplifier emulates the behavior of a Class-C amplifier, the peaking amplifier amplifying the second input signal; and
a Doherty power combiner combining the amplified first input signal and the amplified second input signal to generate an output signal.
12. The Doherty amplifier of claim 11 , wherein a first Class-AB amplifier in the second plurality of Class-AB amplifiers is biased with a very deep Class-AB biasing, wherein the very deep Class-AB biasing is a biasing substantially below four percent of a Class-A biasing.
13. The Doherty amplifier of claim 12 , wherein the first Class-AB amplifier is configured as an output stage of the peaking amplifier.
14. The Doherty amplifier of claim 11 , wherein a second Class-AB amplifier in the second plurality of Class-AB amplifiers is biased with a deep Class-AB biasing, wherein the deep Class-AB biasing is a biasing substantially between four percent and ten percent of a Class-A biasing.
15. The Doherty amplifier of claim 14 , wherein the second Class-AB amplifier is configured as a driver stage of the peaking amplifier.
16. The Doherty amplifier of claim 11 , wherein a third Class-AB amplifier in the second plurality of Class-AB amplifiers is biased with a low Class-AB biasing, wherein the low Class-AB biasing is a biasing substantially of twenty percent or below of a Class-A biasing.
17. The Doherty amplifier of claim 16 , wherein the third Class-AB amplifier is configured as an input stage of the peaking amplifier.
18. The Doherty amplifier of claim 11 , wherein biasing of a second Class-AB amplifier, in the second plurality of Class-AB amplifiers, and a first Class-AB amplifier, in the second plurality of Class-AB amplifiers, are different.
19. The Doherty amplifier of claim 11 , wherein the main amplifier and the peaking amplifier are identically fabricated.
20. The multistage linear power amplifier of claim 1 , wherein the multistage linear power amplifier, emulating the behavior of the Class-C amplifier, exhibits high power added efficiency and gain.