Doherty Power Amplifier Threshold Control for Auxiliary Stage Efficiency

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Solution Overview

Problem

Doherty power amplifiers face inefficiencies due to the auxiliary amplifier's constant operation, which consumes power even when not needed, reducing overall efficiency and increasing heat generation.

Innovation Solution

A controller is implemented to switch the auxiliary amplifier between operational and non-operational states based on input signal voltage, ensuring it operates only when the input voltage exceeds a predetermined threshold, optimizing power usage and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the auxiliary amplifier operates constantly, then the power amplifier can maintain high output power capability, but power consumption increases and efficiency decreases

Engineering Contradiction:
Improveoutput power capabilityVSAvoidpower consumption
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the auxiliary amplifier's operational state variable rather than fixed. The controller dynamically switches the auxiliary amplifier between operational and non-operational states based on real-time input signal voltage levels, allowing the system to adapt power consumption to actual demand while maintaining output power capability when needed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameter of the auxiliary amplifier from a constant state to a variable state controlled by input voltage thresholds. By adjusting the control threshold parameter, the system optimizes the balance between power consumption and output power capability, enabling the auxiliary amplifier to operate only when the input signal exceeds the threshold voltage

Inventive Principle:
Principle #35Parameter changes

2Power

If the auxiliary amplifier operates constantly, then the power amplifier maintains high output power capability, but heat generation increases

Engineering Contradiction:
Improveoutput power capabilityVSAvoidheat generation
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The controller dynamically adjusts the auxiliary amplifier's operational state based on input signal conditions, switching it off when the input voltage is below the threshold. This dynamic control reduces unnecessary heat generation from the auxiliary amplifier while maintaining the power amplifier's ability to deliver high output power when the input signal warrants auxiliary amplifier operation

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If the auxiliary amplifier is switched off, then power consumption decreases and efficiency improves, but output power capability is reduced

Engineering Contradiction:
Improvepower consumptionVSAvoidoutput power capability
Core Design Contradiction:
Use of energy by moving objectVSPower

Solution Approach 1:

The patent implements feedback control by monitoring the input signal voltage and comparing it to a predetermined threshold. The controller uses this feedback information to determine whether the auxiliary amplifier should be operational or non-operational, ensuring that the auxiliary amplifier is activated only when the input signal voltage exceeds the threshold, thus maintaining output power capability only when necessary

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The auxiliary amplifier operates in periodic cycles rather than continuously, being switched on and off based on the input signal voltage relative to the threshold. This periodic operation reduces average power consumption and improves efficiency while maintaining the capability to provide high output power during periods when the input signal exceeds the threshold

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2912769B1Doherty power amplifier
Publication Date: 2019.10.16 AIRSPAN NETWORKS INC
  • EP2912769B1 patent drawingFigure 1

AI summary

A Doherty power amplifier including a main amplifier, an auxiliary amplifier and a controller governing the operation of the auxiliary amplifier, the controller being operative to switch the operational state of the auxiliary amplifier between an operational state and a non-operational state as a function of input signal voltage supplied to the power amplifier such that the auxiliary amplifier is inoperative when the input voltage is below an input voltage threshold and is operative when the input voltage is above the input voltage threshold.