USB Ground Loop Protection via Isolation and Current Limiting
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Solution Overview
Problem
Modern vehicle diagnostic systems face issues with excessive voltage and current, leading to ground loop damage and potential electric shock hazards due to improperly designed or installed equipment, which can cause noise and interference in electrical systems.
Innovation Solution
A system with voltage and current limiting devices integrated into the circuit, including a first power line, a ground line, and a data line, with current limiting devices connected to the ground and data lines to prevent excessive voltage and current from causing damage or injury.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple components are connected together to enable communication and data exchange, then the functionality and versatility of the system is improved, but ground loops may occur causing excessive voltage and current that can damage components and pose safety hazards
Solution Approach 1:
The patent introduces isolation components (optical isolators, transformers, or isolation amplifiers) as intermediary devices between connected components. These intermediaries break the direct electrical connection that causes ground loops while maintaining signal transmission, thus preserving system functionality while eliminating the harmful ground loop effect.
Solution Approach 2:
The patent extracts the ground reference from the signal transmission path by using isolated power supplies and separate ground references for each component. This separation removes the ground loop formation mechanism while allowing components to remain electrically connected for data communication.
2Reliability
If voltage and current are increased to improve signal quality and transmission capability, then the reliability of communication is improved, but the risk of electric shock hazard and component damage increases
Solution Approach 1:
The patent employs isolation techniques that create equipotential zones on each side of the isolation barrier, allowing components to operate at different ground potentials without creating dangerous voltage differences. This maintains safe operating voltages while enabling reliable communication through the isolated interface.
3Measurement precision
If ground points are connected to ensure common reference potential, then measurement accuracy is improved, but ground loops are created causing noise and interference
Solution Approach 1:
The patent uses isolation amplifiers and differential signaling as intermediary mechanisms to maintain precise measurements without requiring direct ground connections. These intermediaries transmit measurement signals while blocking the ground loop path, thus preserving measurement accuracy while eliminating noise and interference.
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
The system effectively protects electrical components and users from ground loop-related damage by ensuring that ground points at different potentials do not cause excessive current flow, thereby reducing the risk of damage and injury.
Implementation Method 1
means for limiting voltage electrically connected to the first power line, the first portion of the ground line, and the first portion of the first data line
Implementation Method 2
a first means for limiting current is electrically connected to the first portion of the ground line and to the second portion of the ground line, and a second means for limiting current is electrically connected to the first portion of the first data line and to the second portion of the first data line
Data Source
AI summary
An apparatus is provided to electrically protect a circuit for USB protection against excessive voltage and/or current such as ground loop damage. A circuit is connected between electrical components where at least one of the connections is a USB connection. There is a possibility for the ground points of the electrical components to be at different voltage potentials and can create a ground loop. The apparatus can include a voltage limiting circuit connected to circuit lines which connect to the USB connection, and circuit breakers or resistors can be connected to the circuit lines between the USB connection and the connection to the other electrical component. In some aspects, the connections at either end of the circuit can all be USB connections. The components of the apparatus protect the connected electrical components from receiving more power than they can tolerate, and protect a user of the electrical components from injury caused by excess power.