Replica Communication Path for High-Bandwidth CMTI Matching

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

High-bandwidth common-mode transient immunity is challenging to achieve across high-voltage isolation barriers, particularly due to device mismatch causing common-mode to differential-mode conversion, which results in signal distortion and attenuation.

Innovation Solution

A system comprising a primary communication path, a replica communication path, and a monitor circuit that cancels common-mode transients by generating adjustment signals to oppose high-bandwidth common-mode transients, with a gain modifier circuit to trim parameters and match signals across paths, ensuring minimal common-mode impedance and maximal differential-mode impedance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a low CM impedance input is used at the receiver interface to counter loading during CMTI events, then common mode transient immunity is improved, but differential-mode signal attenuation increases

Engineering Contradiction:

Improvecommon mode transient immunityVSAvoiddifferential-mode signal attenuation

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The receiver interface is segmented into separate CM and DM impedance control paths. A switch selectively connects either a low CM impedance path or a high DM impedance path based on whether a CMTI event is detected, allowing optimal impedance matching for each operating condition without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The impedance characteristics of the receiver interface are made dynamic through a switch that changes configuration based on CMTI event detection. The system transitions between low CM impedance mode (during transients) and high DM impedance mode (during normal operation), adapting to real-time conditions.

Inventive Principle:

Principle #15Dynamics

2Reliability

If device mismatch is present in the isolation barrier, then common-mode to differential-mode conversion occurs, but achieving high bandwidth CMTI becomes more difficult

Engineering Contradiction:

Improvehigh bandwidth CMTIVSAvoiddevice mismatch

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The system performs preliminary detection of CMTI events and applies counteracting signals before the transient can cause significant distortion. The monitor circuit detects incoming transients and the switch pre-configures the impedance path to counteract the harmful effects of device mismatch during high-bandwidth events.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

A monitor circuit acts as an intermediary between the isolation barrier and the receiver, detecting CMTI events and controlling a switch that mediates the impedance configuration. This intermediary layer compensates for device mismatch effects by dynamically adjusting the interface characteristics.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9548710B2Methods and circuitry to provide common mode transient immunity

Publication Date: 2017.01.17 INFINEON TECHNOLOGIES AMERICAS CORP

AI summary

Embodiments herein include a replica communication path and monitor circuit to provide increased common mode transient immunity. As its name suggests, the monitor circuit monitors the replica communication path and produces an adjustment signal (common mode transient adjustment signal) to cancel presence of a common mode transient signal in one or more other communication paths conveying data signals.