US 6,133,788 A · Hybrid Chireix/Doherty amplifiers and methods

Abstract

Two amplifiers that are driven using outphasing modulation are coupled to one another so that the amplifiers affect each other's effective load line. The two amplifiers can maintain efficiency over a wider dynamic range than in a conventional amplifier. Amplifiers according to the invention amplify an AC input signal of varying amplitude and varying phase using a DC power supply. A converter converts the AC input signal into a first signal having constant amplitude and a first phase angle and into a second signal having constant amplitude and a second phase angle. The first amplifier amplifies the first signal, and the second amplifier amplifies the second signal. A coupler couples the first and second amplifiers to one another and to a load impedance, such that voltages or currents in the first amplifier become linearly related to voltages or currents in the second amplifier. The coupler may include at least one transformer that serially couples the first and second amplifiers to one another and to the load impedance. The coupler may also include first and second quarter wave transmission lines that couple the first and second amplifiers to one another and to the load impedance. The amplifiers preferably use bilateral devices, such that current flows from the first and second amplifiers to the DC power supply during part of a signal cycle, and thereby returns energy to the DC power supply.

Claims18

Dependent claims

A power amplifier that amplifies an AC input signal of varying amplitude and varying phase to produce an amplified output signal voltage and an output current in a load impedance using a DC power supply, comprising:

means for converting the AC input signal of varying amplitude and varving phase into a first signal having constant amplitude and a first varving phase angle and into a second signal having constant amplitude and a second varving phase angle such that the difference between the first and second varving phase angles varies as a function of the AC input signal of varving amplitude and varying phase angle;
first means for amplifying the first signal having constant amplitude and a first varying phase angle to produce a first output signal voltage of constant voltage amplitude, the first amplifying means including bilateral amplifier devices that draw current from the DC power supply and supply current to the DC power supply;
second means for amplifying the second signal having constant amplitude and a second varying phase angle to produce a second output signal voltage of constant voltage amplitude, the second amplifying means including bilateral amplifier devices that draw current from the DC power supply and supply current to the DC power supply;
and
means for coupling the first and second output signal voltages to the load impedance, such that a voltage proportional to the sum of the first and second output signal voltages of constant amplitude produces the amplified output signal voltage across the load impedance and produces the output current through the load impedance, and such that an amplifier current that is linearly related to the output current flows in the bilateral amplifier devices of both the first and second amplifying means.

2 more elements

Dependencies are inferred from the claim text.

Hybrid Chireix/Doherty amplifiers and methods

Life of this patent

Hybrid Chireix/Doherty amplifiers and methods

Life of this patent

Abstract

Claims18