USB Common-Mode Compensation for EFT-Tolerant I/O Communication
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Solution Overview
Problem
USB devices are prone to malfunction, transition into non-operational states, or experience false input readings due to electrical fast transient (EFT) disturbances, which cause common mode voltage fluctuations beyond the normal operational range, leading to data corruption and loss.
Innovation Solution
A common mode compensation circuit that extracts and adjusts the common mode voltage within predetermined acceptable ranges by using detection and comparison circuitry to identify EFT disturbances and processing circuitry to shift the voltage, ensuring it remains within operational limits, thereby preventing errors and maintaining data integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional I/O communication systems are used, then system simplicity is maintained, but susceptibility to electrical fast transient (EFT) noise increases
Solution Approach 1:
The patent introduces an intermediary device (isolator or transformer) between the noisy industrial environment and the microcontroller to block EFT noise while allowing legitimate communication signals to pass through. This intermediary protects the microcontroller without requiring complete system redesign.
Solution Approach 2:
The patent extracts the noise filtering function from the main communication system by using a separate dedicated component (common mode choke or isolator) that specifically targets EFT noise frequencies. This allows the main system to remain simple while adding targeted protection.
2Reliability
If standard I/O ports are used for communication, then ease of operation is maintained, but signal integrity degrades in noisy environments
Solution Approach 1:
The patent uses an isolator as an intermediary that maintains signal integrity by providing galvanic isolation between the microcontroller and the noisy communication line. The isolator preserves the simplicity of I/O operations while blocking noise transmission.
Solution Approach 2:
The patent implements protective measures (common mode chokes, isolators) before the noise can corrupt the signal. These components are positioned in the signal path to pre-filter EFT noise before it reaches sensitive microcontroller pins.
3Productivity
If direct connection to industrial equipment is made, then communication efficiency is improved, but exposure to electrical interference increases
Solution Approach 1:
The patent introduces communication intermediaries (isolators, common mode chokes) that allow efficient communication with industrial equipment while blocking electrical interference. These intermediaries maintain signal transmission efficiency while providing noise isolation.
Solution Approach 2:
The patent uses common mode chokes that exploit the characteristics of EFT noise (common mode voltage spikes) to filter them out while allowing differential mode communication signals to pass through unaffected. The harmful noise characteristics are converted into filterable signals.
Data Source
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AI summary
Apparatuses, systems and methods associated with electrical fast transient tolerant input/output (I/O) communication (e.g., universal serial bus (USB)) design are disclosed herein. In embodiments, an apparatus may include common mode extraction circuitry to extract a common mode voltage from a USB input signal for a USB device, compare the common mode voltage with a reference voltage range and determine, based on the comparison, that the common mode voltage is outside of the reference voltage range. In the embodiments, the apparatus may further include processing circuitry to adjust the common mode voltage to within the reference voltage range. Other embodiments may be described and/or claimed.