Power Stage Drain Voltage Adaptation for Mismatch Protection

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Solution Overview

Problem

Existing power amplifier systems in active antennas face premature aging and potential destruction due to mismatch issues, leading to inefficiency, increased mass, bulk, and cost, with prior solutions like ferrite insulators being bulky and ineffective.

Innovation Solution

A system that integrates a fast DC/DC converter to adapt the drain voltage of a power stage based on the ratio of reflected and incident power, using a coupler, analog device, and switching cell to modulate the drain voltage and protect the power stage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ferrite insulators are installed at the output of power transistor to protect power chains, then reliability is improved, but device complexity and volume increase

Engineering Contradiction:
Improveprotection of power chainsVSAvoidaddition of insulating elements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the ferrite insulator from the system and replaces it with a voltage adaptation circuit that extracts only the necessary protection function. The coupler extracts voltage information about reflected power, and the control circuit extracts only the essential function of protecting the power transistor by adapting drain voltage, eliminating the need for bulky insulators.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/ferrite-based insulator with an electronic control system consisting of a coupler, voltage detection circuit, and switching circuit. This substitution transforms a passive mechanical protection device into an active electronic system that can dynamically adapt drain voltage based on reflected power conditions.

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

2Reliability

If ferrite insulators are installed to protect power chains, then reliability is improved, but weight and volume increase

Engineering Contradiction:
Improveprotection of power chainsVSAvoidmass of antenna system
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent removes the heavy ferrite insulator and replaces it with lightweight electronic components. The coupler, voltage detection circuit, and switching circuit together weigh significantly less than the ferrite insulator, thereby reducing the overall mass of the antenna system while maintaining protection functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If ferrite insulators are installed to protect power chains, then reliability is improved, but cost increases

Engineering Contradiction:
Improveprotection of power chainsVSAvoidcost of antenna system
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses inexpensive electronic components (coupler, voltage detection circuit, switching circuit) to replace expensive ferrite insulators. These electronic components are cheaper to manufacture and integrate into the antenna system, reducing overall cost while providing equivalent or superior protection functionality.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If transistors are oversized to handle mismatch, then reliability is improved, but efficiency deteriorates

Engineering Contradiction:
Improveprotection from mismatchVSAvoidefficiency of power amplifier
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic adaptation of drain voltage based on real-time detection of reflected power conditions. The switching circuit dynamically adjusts the drain voltage to match the load impedance, allowing the transistor to operate efficiently under matched conditions while providing protection during mismatch conditions. This eliminates the need for static oversizing.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the drain voltage parameter dynamically based on the reflection coefficient. By detecting the reflected power through the coupler and adjusting the drain voltage accordingly, the system optimizes the operating parameters of the transistor to maintain high efficiency while protecting against mismatch damage.

Inventive Principle:
Principle #35Parameter changes

5Reliability

If fast response is implemented to protect power stage from mismatch, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveprotection speedVSAvoidswitching cell integration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the voltage adaptation function directly into the power stage by integrating a switching cell within the power amplifier circuitry. This consolidation combines the protection function with the existing power stage components, achieving fast response without proportionally increasing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a feedback loop where the coupler continuously monitors reflected power and feeds this information back to the switching circuit, which rapidly adjusts the drain voltage in response. This feedback mechanism enables fast automatic protection response while using simple, well-established control circuitry.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables quick protection of power stages from mismatch, eliminates the need for bulky insulators, and allows for efficient amplification without oversizing transistors, reducing mass and cost while maintaining high-frequency communication capabilities.

Implementation Method 1

a coupler 5n, whose function is, in particular, to extract the voltages Vi and Vr, which represent the incident and reflected powers

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

a switching cell 7n, which has a function to adapt the value of the drain voltage Vds of the power transistor 3n by switching

Methodology Applied
Scientific EffectVoltage switching:

Data Source

PatentEP4020821B1System for adapting the voltage of a drain of a power stage
Publication Date: 2024.05.01 THALES SA
  • EP4020821B1 patent drawingFigure 1
  • EP4020821B1 patent drawingFigure 2
  • EP4020821B1 patent drawingFigure 3

AI summary

The invention relates to a system for adapting the voltage of a drain of a power stage comprising at least two transmission channels TXn, a transmission channel comprising a resistive element (1n), a phase control module (2n), a power stage (3n) at the output of which is disposed a radiating element (En) characterized in that it comprises at least: - A device (5n) for determining the reflected power value Pr, the incident power value Pi at the level of a power stage, and the power ratio R, - An analog device (6n) configured to modulate said difference signal into pulse widths, - A switching cell (7n) receiving a low power PWM signal and adapted to generate a PWM power signal transformed by a low-pass filter (8n) into a bias signal of the power stage according to a predefined bias control law.