Plasma Switch Fuse for Implantable Medical Device Protection
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Solution Overview
Problem
Implantable medical devices face issues with electrical overstress due to close circuit trace spacing, leading to potential damage from intense local heating and arcing, as traditional fuses do not disconnect quickly enough to protect the remainder of the circuit.
Innovation Solution
Incorporating a plasma switch that connects an overstressed circuit to a ground or negative pole, forming a conductive plasma arc to rapidly divert current away from the affected area, and integrating failure points with lower resistive paths to ground, enhancing the disconnection speed during high voltage, high current, or high power situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional fuse is used to protect the circuit from electrical overstress, then the circuit is protected from damage, but the fuse does not burn out fast enough to fully protect the rest of the circuit during the burning process
Solution Approach 1:
A plasma switch is introduced as an intermediary component between the fuse and the downstream circuit. When the fuse begins to burn out, the plasma switch detects the electrical overstress condition and rapidly opens its contacts, creating a second protective barrier that interrupts current flow to the downstream circuit much faster than the fuse alone could achieve.
Solution Approach 2:
The plasma switch is positioned upstream of the fuse and is configured to detect and respond to electrical overstress conditions before the fuse completes its burning process. By acting preliminarily, the plasma switch interrupts the fault current before it can cause significant damage to the downstream circuit, while the fuse provides backup protection.
2Productivity
If circuit trace spacing is reduced to increase device density, then more components can be integrated, but cross talk and arcing may occur between adjacent circuits
Solution Approach 1:
The harmful electrical overstress and arcing phenomena are extracted and redirected to a dedicated failure point structure. This failure point includes a controlled burnout element and plasma switch that are specifically designed to handle and dissipate excess energy away from the dense circuit traces, allowing close spacing without compromising safety.
Solution Approach 2:
The potential harmful effect of electrical overstress is converted into a beneficial protective mechanism. The failure point structure is designed to intentionally fail in a controlled manner, using the overstress energy to trigger a rapid disconnection through the plasma switch, thereby protecting the main circuit from damage while enabling higher device density.
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 plasma switch effectively reduces current flow to the remainder of the circuit more quickly than traditional fuses, minimizing damage to the device and patient by creating a low resistance path to ground during an overstress event, thus providing improved protection against electrical overstress.
Implementation Method 1
Incorporating a plasma switch that connects an overstressed circuit to a ground or negative pole, forming a conductive plasma arc to rapidly divert current away from the affected area
Implementation Method 2
forming a conductive plasma arc to rapidly divert current away from the affected area
Implementation Method 3
the electrical overstress may cause intense local heating, and circuit burnout
Implementation Method 4
A potential issue with the use of fuse, however, is that the time during which the fuse is burning out may result in significant damage
Data Source
AI summary
An implantable medical device may have a circuit failure mode. The disclosed circuit may have an integrated failure point designed to fail prior to those portions of the circuit. The integrated failure point may include a narrowed portion of a high voltage lead and a grounded lead having a narrow gap separating the grounded lead from the narrowed portion of the high voltage lead. During a high stress fault condition the narrowed portion of the high voltage lead acts as a fuse, forming a vaporized cloud of metal, which shorts current in the high voltage lead across the narrow gap to the grounded lead, thus protecting the remaining portion of the circuit from the high stress condition.