Digital Amplifier Feedforward Voltage Control for Audio Distortion

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing digital amplifier systems with feedback control architectures struggle to follow voltage variations due to the amplifier power block, leading to distortion in audio output signals caused by power supply voltage fluctuations, especially when load variations occur in real-time.

Innovation Solution

A signal amplification apparatus that includes output decrease prediction means, power supply voltage correction signal generation means, and feedforward control means to predict and correct power supply voltage variations in real-time, using a feedforward signal generated by adding input signals from all channels to suppress voltage variations and prevent distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If feedback control is used to maintain constant power supply voltage, then voltage stability is improved, but the system cannot follow real-time voltage variations caused by load changes, leading to distortion

Engineering Contradiction:

Improvevoltage stabilityVSAvoidresponse to load variations

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention generates a feedforward signal based on the input signal amplitude before the power supply voltage variation occurs. This preliminary action allows the system to anticipate and prepare for voltage changes, enabling the power supply to follow load variations in real-time while maintaining stability through the combination of feedforward and feedback control

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If the amplifier power block switches power supply voltage to match signal level, then power efficiency is improved, but voltage variations occur that directly influence audio output and produce distortion

Engineering Contradiction:

Improvepower efficiencyVSAvoidvoltage variation distortion

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The invention combines feedback control from the power source block with feedforward control generated from the input signal. The feedback loop monitors actual voltage variations and corrects them, while the feedforward signal anticipates required voltage changes based on input signal amplitude, working together to eliminate distortion while maintaining power efficiency

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The invention introduces a feedforward signal generation section as an intermediary between the input signal and the power supply control. This intermediary processes the input signal to generate a predictive control signal that mediates between the conflicting requirements of power efficiency and voltage stability

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7528662B2Signal amplification apparatus and signal amplification method

Publication Date: 2009.05.05 SONY GROUP CORP

AI summary

A signal amplification apparatus which supplies an input signal to a signal processing section to perform signal processing on the input signal, amplifies a power supply voltage supplied from a power source section in accordance with the processed signal, and outputs the amplified power supply voltage. The apparatus includes output decrease prediction means for predicting decrease of the output signal on the basis of an amplitude of the input signal; power supply voltage correction signal generation means for generating a power supply voltage correction signal for correcting the power supply voltage of the power source section on the basis of the predicted decrease of the output signal; and feedforward control means for performing feedforward control of the power supply voltage of the power source section by using the power supply voltage correction signal.