Programmable PWM Controller for High-Gain Digital Audio Feedback
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Solution Overview
Problem
Traditional digital audio converters 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 and a butterfly mixer, enabling adaptable and programmable loop filters for robust signal processing, high-resolution ADCs for feedback, and flexible configuration for various applications, including audio amplifiers and active loudspeaker systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gain of an analog feedback loop is increased by increasing its filtering order, then loop gain and suppression of non-idealities is improved, but device complexity and calibration requirements worsen
Solution Approach 1:
The patent replaces the analog loop filter with a digital loop filter implemented in the digital domain. This substitution allows for higher-order filtering (improving suppression of non-idealities) without the physical constraints of analog components, eliminating the need for complex calibration mechanisms and large passive components while maintaining signal integrity throughout the audio frequency range.
Solution Approach 2:
The patent changes the domain from analog to digital, enabling dynamic adjustment of filter parameters through programming rather than physical component adjustment. This allows for flexible modification of filtering characteristics to achieve high loop gain and suppression of non-idealities without increasing physical device complexity or requiring extensive calibration.
2Reliability
If feedback is taken after the output filter in an analog system, then suppression of output filter non-idealities is improved, but device complexity and stability control worsen
Solution Approach 1:
The patent replaces the analog feedback system with a digital feedback system that takes feedback after the output filter. The digital loop filter in the feedback path can implement complex compensation algorithms to maintain stability without requiring large passive components or secondary local feedback loops, thereby achieving suppression of output filter non-idealities with reduced device complexity.
Solution Approach 2:
The patent implements a digital feedback mechanism that samples the output signal after the output filter and feeds it back through a programmable digital loop filter. This allows for effective suppression of non-idealities from the output filter while using digital signal processing to maintain loop stability without the complexity of analog compensation circuits.
3Measurement precision
If a high-resolution ADC with low latency is used for feedback, then signal conversion quality is improved, but device complexity and cost worsen
Solution Approach 1:
The patent implements a single ADC that serves multiple functions: it provides high-resolution feedback for the digital loop filter, enables digital signal processing, and supports various audio processing modes. This multi-functional approach achieves high signal conversion quality without requiring multiple specialized high-end ADCs, thereby reducing overall device complexity and cost.
Data Source
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.