Network Interface Transient Protection for Multiple Ground Planes
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Solution Overview
Problem
Electronic systems are vulnerable to damage from transient energy events like lightning, and existing solutions such as isolating transformers and surge suppressors may not be suitable for all applications, leading to issues with common-mode noise and regulatory compliance.
Innovation Solution
A network interface apparatus with a transient event suppression module that provides a low impedance path to earth ground during transient events, using a power transformer to separate ground levels and a common mode suppression circuit to absorb noise, allowing for the removal of traditional isolators and surge suppressors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isolating transformers and surge suppressors are used to protect against transient events, then device reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines the transient protection function and ground reference function into a single integrated circuit element, eliminating the need for separate isolating transformers and surge suppressors. The integrated circuit provides both protection against transient events and establishes ground references, thereby reducing overall device complexity while maintaining reliability.
Solution Approach 2:
The integrated circuit performs multiple functions simultaneously: it protects against transient events, establishes ground references between different domains, and suppresses common-mode noise. This multi-functionality replaces what previously required multiple separate components, reducing device complexity while maintaining comprehensive protection.
2Reliability
If ground levels are separated to protect against transients, then reliability is improved, but common-mode noise increases
Solution Approach 1:
The integrated circuit acts as an intermediary between different ground domains, providing controlled coupling that establishes stable ground references while blocking the propagation of common-mode noise. This mediator function allows transient protection through ground separation while simultaneously suppressing noise, resolving the contradiction between reliability and noise generation.
3Device complexity
If traditional isolators and surge suppressors are removed to reduce complexity, then device complexity is reduced, but protection capability is worsened
Solution Approach 1:
The patent extracts the essential protection and ground reference functions from complex external components and integrates them into a single circuit element. This extraction eliminates the need for bulky isolating transformers and separate surge suppressors, reducing device complexity while maintaining comprehensive transient protection capability through the integrated solution.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively protects sensitive Physical Layer devices from transient energy events while reducing common-mode noise, ensuring compliance with regulatory standards by directing destructive energy to earth ground and maintaining normal operation impedance.
Implementation Method 1
During a transient event the transient event suppression module provides a low impedance path to the earth ground to protect the PHY device from the transient event
Implementation Method 2
A power circuit that delivers power from a second ground level to the PHY device that is coupled to first ground level. The first ground level and the second ground level are coupled to provide a low impedance path during normal operation
Implementation Method 3
In response to various conditions, electrical current may flow between different ground domains so that the ground levels can move with respect to one another, which may be a source of common-mode noise
Data Source
AI summary
A network interface apparatus is disclosed that includes a connector coupled to a plurality of communication lines. A Physical Layer (PHY) device coupled to the communication lines and to a first ground level. A transient event suppression module coupled between the communication lines and a low impedance path to earth ground. During a transient event the transient event suppression module provides a low impedance path to the earth ground to protect the PHY device from the transient event. A power circuit that delivers power from a second ground level to the PHY device is coupled to the first ground level. The first ground level and the second ground level are coupled to provide a low impedance path during normal operation and high impedance during transient events.