Digital Power Amplifier Pre-Distortion for Gain Error Compensation

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Solution Overview

Problem

Digital Power Amplifiers (DPAs) introduce distortion due to efficiency optimizations, particularly when input amplitude codes are large, affecting the gain characteristic of the RF output.

Innovation Solution

Implement pre-distortion modules to digitally correct the gain characteristic of DPAs by applying configured distortion to input signals, canceling non-linear gain effects and reducing PM-AM and AM-PM distortions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If efficiency optimization techniques are applied in high power DPA, then power consumption is reduced, but distortion is introduced in the gain characteristic

Engineering Contradiction:

Improvepower consumptionVSAvoidgain characteristic accuracy

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent applies pre-distortion to the input signal before it reaches the DPA. The pre-distortion module modifies the input signal in advance to counteract the expected non-linear gain effects of the DPA, thereby canceling out distortion at the output while maintaining the efficiency benefits of the optimized DPA architecture

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The pre-distortion technique introduces an opposite distortion to the input signal that anticipates and counteracts the non-linear gain distortion produced by the DPA. This preliminary anti-action ensures that the combined effect results in linear gain characteristic at the output

Inventive Principle:

Principle #9Preliminary anti-action

2Area of stationary object

If Digital Power Amplifier integrates multiple functions (DAC, frequency up-converter, PA), then chip area is reduced, but distortion is introduced when input amplitude codes are large

Engineering Contradiction:

Improvechip areaVSAvoidgain characteristic accuracy

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The pre-distortion module processes the input signal in advance to compensate for the non-linear gain effects introduced by the integrated DPA architecture, ensuring accurate gain characteristic despite the integration of multiple functions in a compact chip area

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The pre-distortion module acts as an intermediary between the input signal and the integrated DPA, modifying the signal to account for the non-linearities introduced by the integrated architecture, thereby enabling both compact size and accurate gain characteristic

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20260019096A1Compensation methods and devices for digital power amplifier

Publication Date: 2026.01.15 MORSE MICRO PTY LTD

AI summary

Systems and techniques are provided for power amplifier gain error compensation for a Digital Power Amplifier (DPA). In some aspects, a compensation method includes obtaining in-phase (I) and quadrature-phase (Q) components of a baseband sample corresponding to in-phase input amplitude codes and quadrature-phase input amplitude codes. The in-phase input amplitude codes can be distorted based on first gain pre-compensation information corresponding to an in-phase signal branch of the DPA, to generate pre-distorted output amplitude codes of the I component. The quadrature-phase input amplitude codes can be distorted based on second gain pre-compensation information corresponding to a quadrature-phase signal branch of the DPA, to generate pre-distorted output amplitude codes of the Q component. The DPA can be driven using the pre-distorted output amplitude codes of the I and Q components to generate a Radio Frequency (RF) output.