Digital Doherty Power Amplifier Autotuning for Broadband Linearity

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Solution Overview

Problem

Traditional analog Doherty Power Amplifiers (DPAs) face limitations in energy efficiency and operational bandwidth due to fixed configurations and the need for manual tuning of circuit parameters, which are not adaptable to varying input signals and environmental changes.

Innovation Solution

A digital Doherty Power Amplifier (DDPA) system with an adaptive control circuit that uses a processor and memory to determine optimal control parameters through an adaptive control algorithm, incorporating transfer learning and curve fitting functions to optimize efficiency and gain across different signal conditions, including frequency and power variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traditional analog DPA with fixed configuration is used, then device complexity is reduced, but adaptability to varying input signals and environmental changes deteriorates

Engineering Contradiction:
Improvecircuit configuration complexityVSAvoidadaptability to varying input signals
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic adaptability by introducing a control circuit that receives feedback signals and automatically adjusts circuit parameters including phase alignment and power splitting ratio. This transforms the fixed analog DPA into a dynamically adjustable system that can adapt to varying input signals and environmental conditions without increasing fundamental circuit complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms where output signals are monitored and fed back to the control circuit. This feedback loop enables automatic adjustment of control parameters to optimize performance under different operating conditions, resolving the contradiction between fixed configuration and adaptability.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If manual tuning of circuit parameters is performed, then manufacturing precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvecircuit parameter precisionVSAvoidtuning process simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent implements self-service through an automatic control circuit that performs parameter tuning without manual intervention. The control circuit autonomously adjusts phase alignment and power splitting ratios based on feedback signals, eliminating the need for manual tuning while maintaining high precision. This resolves the contradiction by making the system self-adjusting rather than requiring operator skill and time.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical tuning with an electronic control system. Instead of physically adjusting circuit parameters, the system uses electronic control signals to automatically optimize performance, substituting human operation with automated electronic adjustment mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If compensation circuit is added to improve performance, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveperformance consistencyVSAvoidcompensation circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent achieves reliability improvement through a control circuit that performs multiple functions: phase alignment adjustment, power splitting ratio optimization, and performance monitoring. This multi-functional approach consolidates what would otherwise require separate compensation circuits into a single integrated control system, maintaining reliability while managing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3954041B1Power amplifier system and transfer learning-based autotuning optimization method thereof
Publication Date: 2023.06.14 MITSUBISHI ELECTRIC CORP
  • EP3954041B1 patent drawingFigure 1
  • EP3954041B1 patent drawingFigure 2
  • EP3954041B1 patent drawingFigure 3A

AI summary

A Digital Power- Amplifier (DPA) system includes a power amplifier (PA) circuit having control inputs and an output for generating output signals, and an adaptive control circuit that comprises an input interface, an output interface, a memory storing an adaptive control algorithm and a processor performing instructions based on the adaptive control algorithm in connection with the memory, wherein the input interface receives input-state signals and output signals of the DP A circuit, wherein the adaptive control algorithm determines, in response to the input-state signals and the output signals, control parameters of control signals transmitted to the control inputs from the output interface for controlling operations of the DP A circuit.