Segmented Power Amplifier for Low-Level Gain and Distortion Control

Solution Overview

Problem

Existing power amplifiers face issues with undesired system behavior and inefficiency at low output levels due to coupling between input and output stages, leading to amplitude and phase distortions, as well as increased power consumption.

Innovation Solution

A segmented power amplifier system that allows selective disabling of driver and output stages using control signals, reducing power consumption and minimizing leakage signals by only activating the necessary stages for the required output level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single variable gain output stage is used to control output amplitude over a wide range, then the amplifier can achieve wide gain control range, but coupling between input and output causes amplitude and phase distortion at low output levels

Engineering Contradiction:

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The amplifier is divided into multiple driver stages (first driver stage, second driver stage) and an output stage, where each stage can be independently controlled. This segmentation allows the system to switch between different stage configurations depending on the required output level, thereby avoiding the coupling distortion problem that occurs in single-stage amplifiers at low output levels.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The amplifier dynamically switches between different operational modes: at high output levels, all stages are active; at low output levels, the first driver stage is disabled and only the second driver stage and output stage are active. This dynamic reconfiguration optimizes performance for different operating conditions, preventing amplitude and phase distortion at low levels while maintaining wide gain control range.

Inventive Principle:

Principle #15Dynamics

2Reliability

If all driver and output stages are always active to maintain signal integrity, then amplitude and phase response are maintained, but power consumption increases at low output levels

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The amplifier employs dynamic stage disabling controlled by control circuitry that monitors the required output level. When the output level is low, the control circuitry disables the first driver stage, reducing power consumption. When the output level is high, all stages are enabled to maintain signal integrity. This dynamic adaptation resolves the contradiction between power efficiency and signal integrity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Different stages of the amplifier are assigned different operational states based on local requirements: the first driver stage is disabled when its contribution is not needed for low output levels, while the second driver stage and output stage remain active to maintain signal integrity. This localized control of stage activation optimizes both power consumption and signal quality.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If output stage gain is reduced to achieve low output amplitudes, then the desired low amplitude output is produced, but coupling causes the output to deviate from desired response and cannot reach zero amplitude

Engineering Contradiction:

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The amplifier segments the signal path into multiple independently controllable stages. At low output levels, the first driver stage is disabled, effectively removing its contribution to the output signal and eliminating the coupling distortion it introduces. This allows the output amplitude to be accurately controlled down to near-zero levels without the degradation caused by coupling in single-stage amplifiers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention converts the potentially harmful effect of coupling distortion into a benefit by selectively disabling the first driver stage at low output levels. This disables the coupling path that would otherwise cause amplitude and phase distortion, allowing the amplifier to achieve accurate low amplitude output control that would be impossible in a continuously active single-stage configuration.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Reliability

If driver stages operate at low gains to maintain signal strength, then signal integrity is maintained, but power consumption becomes comparable to or greater than output stage power consumption

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The amplifier dynamically adjusts which driver stages are active based on the required output level. At low output levels, the first driver stage is disabled, eliminating its power consumption while the second driver stage and output stage continue to operate to maintain signal integrity. At high output levels, all stages are active. This dynamic stage management ensures power consumption efficiency while maintaining adequate signal strength through the active stages.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7649411B2Segmented power amplifier

Publication Date: 2010.01.19

AI summary

A system for amplifying a signal is provided. The system includes a plurality of driver stages, each having an input, an output, and a disable control. An output stage having an input is coupled to the outputs of the plurality of driver stages. A plurality of disable control signals is provided to the driver stages so as to controllably enable and disable one or more of the driver stages.