US 7,741,903 B2 · Distortion-driven power amplifier power supply controller

Abstract

A power amplifier controller measures the distortion of a power amplifier output. Based upon the distortion measured, the supply voltage to the PA is adjusted in a control loop. In one embodiment, distortion is measured by computing the ratio of the measured power in the output frequencies outside the desired output channel to the measured power in the output frequencies within the desired channel. If the distortion measured from the PA is higher than a target distortion level, the power supply voltage is raised. If the distortion measured from the PA is lower than the target distortion level, the power supply voltage is reduced. Thus, the supply voltage to the PA is maintained at the lowest possible voltage level, improving the efficiency of the PA.

Claims26

Dependent claims

A radio frequency (RF) power amplifier circuit comprising:

a power amplifier coupled to receive and amplify an input signal to generate an output signal;
a distortion measurement module receiving the output signal of the power amplifier and determining a measured distortion level of the output signal of the power amplifier;
a comparator receiving the measured distortion level from the distortion measurement module and a target distortion level, and generating a power supply control signal indicative of a difference between the measured distortion level and the target distortion level;
and
a power supply coupled to receive the power supply control signal from the comparator and adjust a supply voltage to the power amplifier based on the power supply control signal,
wherein the measured distortion level comprises a ratio of a first output power of a first portion of the output signal outside a desired frequency channel to a second output power of a second portion of the output signal within the desired frequency channel.

3 more elements

A radio frequency (RF) power amplifier circuit comprising:

a power amplifier coupled to receive and amplify an input signal to generate an output signal;
a distortion measurement module receiving the output signal of the power amplifier and determining a measured distortion level of the output signal of the power amplifier;
a comparator receiving the measured distortion level from the distortion measurement module and a target distortion level, and generating a power supply control signal indicative of a difference between the measured distortion level and the target distortion level;
and
a power supply coupled to receive the power supply control signal from the comparator and adjust a supply voltage to the power amplifier based on the power supply control signal, wherein the distortion measurement module comprises:
a desired channel filter filtering the output signal of the power amplifier, wherein the desired channel filter passes frequencies of the output signal within the desired frequency channel and removes frequencies of the output signal outside the desired channel;
a first power detector receiving the filtered output signal from the desired channel filter and generating a desired channel output power signal indicative of a power level of the filtered output signal received from the desired channel filter;
an outside desired channel filter filtering the output signal of the power amplifier, wherein the outside desired channel filter passes frequencies within one or more frequency ranges outside the desired frequency channel and removes frequencies of the output signal within the desired channel;
a second power detector receiving the filtered output signal from the outside desired channel filter and generating an outside desired channel output power signal indicative of a power level of the filtered output signal received from the outside desired channel filter;
and
a ratio calculation module receiving the desired channel output power signal and the outside desired channel output power signal and computing a ratio of the outside desired channel output power signal to the desired channel output power signal, wherein the ratio is indicative of the measured distortion level.

8 more elements

A power amplifier controller circuit for controlling a power amplifier, the power amplifier coupled to receive and amplify an input signal to generate an output signal, the power amplifier biased by a supply voltage provided by a power supply, the power amplifier controller circuit comprising:

a distortion measurement module receiving the output signal of the power amplifier and determining a measured distortion level of the output signal of the power amplifier;
and
a comparator receiving the measured distortion level from the distortion measurement module and a target distortion level, and generating a power supply control signal indicative of a difference between the measured distortion level and the target distortion level, wherein the power supply control signal is outputted to the power supply and causes the power supply to adjust the supply voltage to the power amplifier based on the power supply control signal,
wherein the measured distortion level comprises a ratio of a first output power of a first portion of the output signal outside a desired frequency channel to a second output power of a second portion of the output signal within the desired frequency channel.

1 more element

a distortion measurement module receiving the output signal of the power amplifier and determining a measured distortion level of the output signal of the power amplifier;
and
a comparator receiving the measured distortion level from the distortion measurement module and a target distortion level, and generating a power supply control signal indicative of a difference between the measured distortion level and a target distortion level, wherein the power supply control signal is outputted to the power supply and causes the power supply to adjust the supply voltage to the power amplifier based on the power supply control signal, wherein the distortion measurement module comprises:
a desired channel filter filtering the output signal of the power amplifier, wherein the desired channel filter passes frequencies of the output signal within the desired frequency channel and removes frequencies of the output signal outside the desired channel;
a first power detector receiving the filtered output signal from the desired channel filter and generating a desired channel output power signal indicative of a power level of the filtered output signal received from the desired channel filter;
an outside desired channel filter filtering the output signal of the power amplifier, wherein the outside desired channel filter passes frequencies within one or more frequency ranges outside the desired frequency channel and removes frequencies of the output signal within the desired channel;
a second power detector receiving the filtered output signal from the outside desired channel filter and generating an outside desired channel output power signal indicative of a power level of the filtered output signal received from the outside desired channel filter;
and
a ratio calculation module receiving the desired channel output power signal and the outside desired channel output power signal and computing a ratio of the outside desired channel output power signal to the desired channel output power signal, wherein the ratio is indicative of the measured distortion level.

6 more elements

Dependencies are inferred from the claim text.

Distortion-driven power amplifier power supply controller

Life of this patent

Distortion-driven power amplifier power supply controller

Life of this patent

Abstract

Claims26