Audio Ground Switch Crosstalk Cancellation in USB Stereo Circuits
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Solution Overview
Problem
Existing audio signal processing technologies face challenges in effectively canceling crosstalk in USB interface circuits, particularly in small form-factor devices like smartphones and tablets, due to the complexity and cost associated with additional FETs and wiring required for crosstalk sensing and cancellation.
Innovation Solution
A crosstalk cancellation system that includes an audio interface, digital-to-analog converters, summers, and a crosstalk canceller, which processes digital audio signals to generate crosstalk-compensated analog signals, eliminating the need for additional off-chip FETs and associated IC pins, PCB wiring, and star connections, thereby simplifying the circuitry and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional FETs and wiring are used for crosstalk sensing and cancellation, then crosstalk cancellation effectiveness is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the crosstalk sensing function from the traditional approach that requires separate FETs and wiring, and integrates it into the existing ground switch structure. By utilizing the ground switch's inherent properties and adding minimal circuitry, the system achieves crosstalk sensing without the complexity of dedicated sensing components.
Solution Approach 2:
The ground switch serves multiple functions: it provides the common ground connection for the stereo audio output and simultaneously enables crosstalk sensing. By making the ground switch multi-functional, the patent eliminates the need for separate FETs and wiring dedicated to crosstalk sensing, thereby reducing device complexity while maintaining cancellation effectiveness.
2Reliability
If additional FETs and wiring are used for crosstalk sensing and cancellation, then crosstalk cancellation effectiveness is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the need for additional expensive components (FETs, extra wiring) by extracting the sensing function from the traditional architecture and implementing it through the existing ground switch infrastructure, thereby reducing bill of materials cost and simplifying assembly processes.
Solution Approach 2:
By making the ground switch multi-functional (serving both as ground connection and sensing element), the patent reduces the total component count and assembly steps, directly lowering manufacturing costs while maintaining the required crosstalk cancellation performance.
3Difficulty of detecting and measuring
If additional off-chip FETs and IC pins are used, then crosstalk sensing capability is improved, but PCB wiring complexity and star connections increase
Solution Approach 1:
The patent extracts the sensing capability from the traditional approach requiring separate off-chip FETs and multiple IC pins, and implements it using the ground switch's inherent electrical properties. This eliminates the need for additional PCB trace routing and star connections, significantly reducing PCB wiring complexity.
Data Source
AI summary
An aspect of the disclosure relates to an apparatus, including an audio interface including first and second outputs; a crosstalk cancelling circuit including first and second inputs coupled to the first and second outputs of the audio interface, respectively; a first summer including a first input coupled to the first output of the audio interface and a second input coupled to a first output of the crosstalk cancelling circuit; a second summer including a first input coupled to the second output of the audio interface and a second input coupled to a second output of the crosstalk cancelling circuit; a first digital to analog converter (DAC) including an input coupled to an output of the first summer; and a second DAC including an input coupled to an output of the second summer.