Digital PWM Audio Controller With High-Resolution Feedback Loops

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Solution Overview

Problem

Traditional digital audio converter and amplifier controllers face limitations in achieving high loop gain and suppressing non-idealities in switching amplifiers and output filters due to moderate filter complexity and variability in analog components, requiring complex calibration and large passive components.

Innovation Solution

A programmable pulse width modulating (PWM) controller with multiple parallel loop filters, butterfly mixers, and adaptable ADCs, enabling flexible configuration and high-resolution feedback loops for improved signal processing and error suppression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gain of an analog feedback loop is increased by increasing its filtering order, then error suppression is improved, but device complexity and calibration requirements increase

Engineering Contradiction:
Improveerror suppressionVSAvoidfilter complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the analog feedback loop with a digital feedback loop that uses an ADC to digitize the output signal. This substitution allows the use of digital signal processing techniques instead of complex analog filtering, achieving high-order filtering effects through software algorithms while maintaining lower hardware complexity.

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

Solution Approach 2:

The invention changes the operating parameters by moving from analog to digital domain. The digital controller can dynamically adjust filter coefficients and loop gain parameters without physical component changes, enabling high loop gain and complex filtering through programmable parameters rather than fixed hardware components.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If an ADC with high resolution and low latency is used, then signal conversion quality is improved, but cost increases

Engineering Contradiction:
Improvesignal conversion qualityVSAvoidcost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent designs the ADC to serve multiple functions: it not only converts the output signal for feedback but also provides high-resolution measurement capabilities for various control parameters. This multi-functionality justifies the use of a higher-performance ADC by extracting maximum value from a single component.

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

Solution Approach 2:

The invention implements a feedback mechanism where the ADC output is fed back to the digital controller, creating a closed-loop system. This feedback allows continuous monitoring and correction, improving overall system performance and justifying the investment in a high-quality ADC through measurable performance gains.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3443667B1Digital audio converter and amplifier controller
Publication Date: 2020.06.10 AXIGN BV
  • EP3443667B1 patent drawingFigure 1a~1c
  • EP3443667B1 patent drawingFigure 1d~2b
  • EP3443667B1 patent drawingFigure 2a~7

AI summary

The present invention is in the field of programmable pulse width modulator (PWM) controller comprising filters and a mixer, such as for use in a digital audio converter and digital amplifier controller, a chip comprising said PWM controller, a device comprising said PWM controller or said chip, as well as uses thereof.