Defibrillator Bias Rectification Circuit for Compact AED Waveforms
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Solution Overview
Problem
Conventional public access automated external defibrillators (AEDs) are bulky, costly, and complex, limiting their availability and effectiveness in addressing sudden cardiac arrest (SCA) outside public places, as they require frequent maintenance and are not conveniently portable, leading to high failure rates and unavailability during emergencies.
Innovation Solution
AEDs with a bias generation circuit utilizing diode power rectification and isolated sub-circuits for generating high voltage therapeutic waveforms, reducing size, cost, and complexity by eliminating the need for bulky transformers and enabling a pocket-sized, disposable design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional public access AEDs are designed with reusability, elimination of failure modes, and telemetry functionality, then reliability is improved, but device complexity and size increase
Solution Approach 1:
The AED is divided into two separate components: a disposable defibrillator unit containing the capacitor and shock delivery circuitry, and a reusable charger unit containing the power supply and control electronics. This segmentation allows the disposable unit to be simple and reliable for shock delivery, while the reusable unit handles complex functions like battery management and telemetry, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The defibrillator capacitor and associated high-voltage circuitry are packaged in a disposable unit that is discarded after a single use or when the capacitor degrades. This eliminates the need to design these critical components for long-term reusability and constant self-testing, reducing complexity and size while maintaining reliability for the critical shock delivery function.
2Reliability
If conventional public access AEDs are designed for constant self-testing and reusability, then reliability is improved, but weight and portability worsen
Solution Approach 1:
By separating the disposable defibrillator from the reusable charger, the weight of heavy battery and power management components is concentrated in the charger unit. The disposable unit becomes lightweight, containing only the capacitor and minimal electronics, making it portable and suitable for public access deployment while the charger handles all heavy-duty components.
Solution Approach 2:
The disposable nature of the defibrillator unit eliminates the need for heavy-duty rechargeable batteries and complex power management systems in the portable unit. Only the essential capacitor and shock delivery circuitry are included in the lightweight disposable package, while the charger unit contains all heavy power components.
3Reliability
If conventional public access AEDs are designed with constant self-testing functionality, then reliability is improved, but battery energy consumption increases
Solution Approach 1:
The self-testing and battery management functions are relocated to the reusable charger unit, which has its own power supply. The disposable defibrillator unit requires minimal energy and no self-testing capability, as it is replaced rather than maintained. This eliminates continuous battery drain in the portable unit while maintaining system reliability through charger-based monitoring.
Solution Approach 2:
The disposable defibrillator unit is designed without complex self-testing circuitry or rechargeable batteries. Its simplicity minimizes energy consumption, and its disposable nature means it never needs to be recharged or maintained, eliminating the trade-off between self-testing and energy consumption in the portable unit.
4Power
If conventional public access AEDs are designed with transformer-based bias generation, then high voltage generation is achieved, but device size and cost increase
Solution Approach 1:
The patent replaces the mechanical transformer-based bias generation system with a solid-state voltage multiplier circuit using diodes and capacitors. This electronic substitution eliminates bulky magnetic components, reduces device size and cost, while maintaining the ability to generate the required high voltages for defibrillation shock delivery.
Solution Approach 2:
The disposable defibrillator unit incorporates the simplified solid-state voltage multiplication circuitry rather than transformers, reducing the size and cost of the disposable package. The complex high-voltage generation is achieved through compact electronic means in the disposable unit, while the reusable charger handles power management.
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 new design allows for a compact, affordable, and reliable AED that can be ubiquitously available, increasing survival chances from SCA by ensuring immediate access and reducing the risk of malfunction.
Implementation Method 1
AEDs with a bias generation circuit utilizing diode power rectification
Data Source
AI summary
In one embodiment, a defibrillator is provided. The defibrillator includes a bias generation circuit that includes: a switching regulator, wherein the switched output of the regulator is connected to an input of a primary winding of a transformer and wherein an output of the primary winding of the transformer is rectified to create a regulated DC voltage which powers a microcontroller that is in control of a solid-state therapeutic defibrillation waveform generator; one or more secondary windings of the transformer whose energy is rectified by a diode, wherein the rectified energy is used to supply one or more bias voltages to the solid-state therapeutic defibrillation waveform generator that is used to create one or more therapeutic defibrillation waveforms; and the diode.