H-Bridge Biphasic Defibrillator Circuit Using Series Thyristors
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Solution Overview
Problem
Defibrillators require high-voltage components that increase product costs, making it challenging to manufacture and distribute automated external defibrillators (AEDs) widely due to the complexity and cost of high-voltage withstanding switches.
Innovation Solution
A defibrillator design using a biphasic pulse generation circuit with an H-bridge type configuration, where switches are connected in series with thyristors or IGBTs, and resistors are connected in parallel to divide voltage, along with a common gate signal line to synchronize IGBTs and a series inductor to manage voltage sharing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-voltage components are used in the discharge section to withstand the maximum defibrillation voltage of about 2000V, then the reliability and safety of the defibrillator are improved, but the device complexity and product cost increase significantly
Solution Approach 1:
The discharge section is divided into multiple switching sections (first switching section with first and second switches, second switching section with third and fourth switches) that can operate independently. Each switching section uses lower-voltage components that are connected in series to achieve the required high-voltage withstanding capability, thereby reducing individual component complexity while maintaining overall reliability
Solution Approach 2:
The patent transitions from using single high-voltage switches to a multi-dimensional switching architecture where multiple lower-voltage switches are arranged in series combinations. This dimensional expansion allows the system to achieve high-voltage capability through component arrangement rather than requiring inherently high-voltage components
2Reliability
If high-voltage components are used in the discharge section to withstand the maximum defibrillation voltage of about 2000V, then the safety and performance of the defibrillator are improved, but the product cost increases
Solution Approach 1:
The discharge section is divided into multiple switching sections (first switching section with first and second switches, second switching section with third and fourth switches) that can operate independently. Each switching section uses lower-voltage components that are connected in series to achieve the required high-voltage withstanding capability, thereby reducing individual component complexity while maintaining overall reliability
Solution Approach 2:
The patent employs lower-voltage switching components that are cheaper and more readily available than high-voltage alternatives. By using multiple inexpensive lower-voltage switches in series combinations, the system achieves the required high-voltage performance at reduced component cost
3Adaptability or versatility
If multiple switching sections are used to output a biphasic pulse, then the therapeutic effectiveness of the defibrillator is improved, but the device complexity and product cost increase
Solution Approach 1:
The switching sections are designed with multi-functionality where the same basic switching structure (two switches per section) can produce both monophasic and biphasic pulse waveforms by different control sequences. The first and second switches work together to generate the first phase, while the third and fourth switches generate the second phase, allowing a single circuit architecture to handle multiple defibrillation requirements
Solution Approach 2:
The discharge section is divided into multiple switching sections (first switching section with first and second switches, second switching section with third and fourth switches) that can operate independently. Each switching section uses lower-voltage components that are connected in series to achieve the required high-voltage withstanding capability, thereby reducing individual component complexity while maintaining overall reliability
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 design reduces the cost of defibrillators by using lower-voltage components while maintaining functionality, preventing component damage and ensuring reliable operation.
Implementation Method 1
a plurality of thyristors are connected in series and a resistor is connected in parallel to each of the plurality of thyristors
Implementation Method 2
a series inductor to manage voltage sharing
Data Source
AI summary
A defibrillator of the present disclosure includes a H-bridge type biphasic pulse generation circuit connected to the rear stage side of a high-voltage capacitor. The biphasic pulse generation circuit includes a first switch, a second switch connected in parallel to the first switch, a third switch connected in series and to the rear stage side of the first switch, and a fourth switch connected in series and to the rear stage side of the second switch. The biphasic pulse generation circuit outputs a biphasic pulse from a first output line connected to a connection intermediate point between the first and third switches and from a second output line connected to a connection intermediate point between the second and fourth switches. In at least one of the first switch to the fourth switch, a plurality of thyristors are connected in series, and a resistor is connected in parallel to each thyristor.