Bridge-Rectified Bias Circuit for Pocket-Sized AED Waveforms
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional public access automated external defibrillators (AEDs) are bulky, expensive, and complex, limiting their availability and effectiveness in addressing sudden cardiac arrest (SCA) outside public locations, particularly in homes and during daily activities, due to design choices that prioritize reusability and failure prevention, leading to high costs and impractical size.
Innovation Solution
AEDs are redesigned with a bias generation circuit utilizing bridge power rectification and isolated sub-circuits to generate high-voltage therapeutic waveforms, reducing size and cost by eliminating bulky transformers and complex components, enabling a pocket-sized, disposable design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional AEDs are designed with reusability and failure prevention features, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The AED is divided into two distinct parts: a disposable defibrillator unit containing the battery, capacitor, and defibrillation circuitry, and a reusable controller unit containing the microcontroller and user interface. This segmentation allows the complex reusable portion to be built once with high reliability components, while the disposable portion can use simpler components that are replaced after each use, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The defibrillator unit is designed as a disposable component that is discarded after a single use or when the battery is depleted. This eliminates the need to design for long-term reusability and repeated charging cycles, allowing the use of simpler, less expensive components while maintaining high reliability for the critical defibrillation function during its service life.
2Reliability
If conventional AEDs are designed for reusability and constant self-testing, then reliability is improved, but battery depletion and component wear increase
Solution Approach 1:
By separating the battery and energy storage components into the disposable defibrillator unit from the reusable controller, the system can perform self-tests on the reusable portion without depleting the battery. The disposable unit is replaced rather than recharged, eliminating the trade-off between testing frequency and battery life.
Solution Approach 2:
The disposable nature of the defibrillator unit means that extensive self-testing and readiness checks are performed on the reusable controller without concern for battery depletion. The disposable unit is simply replaced when needed, eliminating the need to balance testing frequency against battery conservation.
3Power
If conventional AEDs are designed with transformer-based bias generation, then high voltage generation is achieved, but device size and weight increase
Solution Approach 1:
The patent replaces the mechanical transformer-based bias generation system with a solid-state voltage multiplier circuit using capacitors and diodes. This electronic substitution eliminates the need for heavy magnetic components while achieving the same high voltage output, directly resolving the contradiction between power output and device weight.
Solution Approach 2:
The invention changes the operating parameters of the defibrillator by using high-frequency switching in the voltage multiplier circuit rather than low-frequency transformer operation. This parameter change allows for smaller, lighter components while maintaining the required voltage output levels.
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 redesigned AEDs become more accessible and reliable, increasing survival chances from SCA by being easily carried and used anywhere, as they are smaller, cheaper, and less prone to failure, thus addressing the limitations of conventional AEDs.
Implementation Method 1
one or more secondary windings of the transformer whose energy is rectified by a bridge rectifier, wherein the rectified energy is used to supply one or more bias voltages
Data Source
AI summary
AED pulse generation circuits that provide floating, adjustable, bias voltages for driving a solid-state defibrillation waveform therapy generator circuit are provided. The provided bias voltages allow to reverse polarity of provided electric shock to increase chances of successful defibrillation and survival. In one of the provided configurations, energy stored in the pulse capacitor can be discharged by activating the waveform therapy generator in the high-resistance transconductance region. The circuits can be positioned on a self-contained module potted with an insulating material to reduce unintended interactions with other AED components. Through the use of the disclosed circuits, AED size can be reduced to promote pocketability while simultaneously increasing AED reliability.