Pulsed Field Ablation Circuit Parasitic Capacitance
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Solution Overview
Problem
Pulsed field ablation systems face challenges with semiconductor switches due to parasitic capacitance, leading to potential short circuits and reduced efficiency, especially in multi-electrode systems, which can result in unsafe and inefficient treatment of tissue.
Innovation Solution
The system incorporates a high voltage pulse generation circuit and an output pulse generation circuit with capacitors and a controller system to manage high voltage pulses, controlling rise times and voltages to minimize parasitic capacitance effects, using Class-Y capacitors and switch configurations to prevent direct current flow and enhance safety and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If semiconductor switches are used to generate high voltage pulses for pulsed field ablation, then the system can deliver high voltage pulses in rapid succession, but parasitic capacitance causes current leakage and potential short circuits reducing safety and efficiency
Solution Approach 1:
The patent extracts and removes the problematic semiconductor switches from the high voltage pulse generation circuit. Instead of using semiconductor switches, the invention employs a capacitor-based circuit that generates high voltage pulses through capacitive coupling and resonant oscillation, completely eliminating the parasitic capacitance issue inherent in semiconductor switches.
Solution Approach 2:
The patent introduces an intermediary LC resonant circuit between the high voltage power source and the tissue target. This intermediary circuit uses inductors and capacitors to generate and shape the high voltage pulses, acting as a mediator that avoids direct semiconductor switch contact with the high voltage output, thereby eliminating parasitic capacitance effects.
2Measurement precision
If multiple electrodes are used to increase treatment precision and area, then more semiconductor switches are required, but parasitic capacitance effects are exacerbated leading to greater current leakage and efficiency loss
Solution Approach 1:
The patent segments the multi-electrode system into independent capacitive pulse generation channels. Each electrode or electrode group has its own dedicated capacitor that can be independently charged and discharged, allowing precise control of pulses to multiple electrodes simultaneously without the cumulative parasitic capacitance problems of semiconductor switches.
Solution Approach 2:
The patent creates a universal capacitive pulse generation platform that can serve multiple electrodes through a shared high voltage power source and capacitor bank. The system can selectively activate any combination of electrodes by switching individual capacitive channels, providing multi-functionality without proportionally increasing parasitic capacitance losses.
3Productivity
If high voltage pulses with sub-second duration are applied to target tissue, then cell membranes are ruptured achieving ablation, but semiconductor switch failure could create dangerous direct connection between patient and high voltage power source
Solution Approach 1:
The patent implements beforehand cushioning by using inherently safe capacitor-based circuitry that cannot fail in a short-circuit manner. The capacitive coupling and resonant circuit design provide natural current limiting and isolation, cushioning against the potential harmful effects of component failure and preventing dangerous direct connections between the patient and high voltage power source.
Solution Approach 2:
The patent employs simple, fail-safe capacitive components that are inherently more reliable than complex semiconductor switches. The circuit uses basic passive components (capacitors, inductors, resistors) that cannot create dangerous short circuits, providing a inherently safer architecture for high voltage pulse delivery to tissue.
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
This configuration reduces the risk of short circuits, limits parasitic capacitance effects, and improves the safety and efficiency of pulsed field ablation treatments by controlling voltage and current flow, allowing for more precise and effective tissue ablation.
Implementation Method 1
an output pulse generation circuit with capacitors and a controller system to manage high voltage pulses
Implementation Method 2
In PFA, high voltage pulses with sub-second pulse durations are applied to target tissue. In some cases, the high voltage pulses rupture cell membranes by forming pores which allow leakage of cell contents, eventually resulting in cell death.
Data Source
AI summary
Pulsed field ablation systems are disclosed, some of which may include an output pulse generation circuit and a high voltage pulse generation circuit electrically connected to the output pulse generation circuit. The high voltage pulse generation circuit may be configured to deliver a high voltage pulse set to the output pulse generation circuit. The output pulse generation circuit may be configured to generate an output pulse set at least in response to the high voltage pulse set. The output pulse set may be deliverable to a set of selectable electrodes and may be configured to cause pulsed field ablation of tissue. Each pulse in the output pulse set may have a rise time that is shorter than a rise time of at least one high voltage pulse in the high voltage pulse set.