Electrohydraulic Shockwave Circuit for Critically Damped Pulses
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Solution Overview
Problem
Conventional electrohydraulic shock wave generators suffer from slow rise times, broad pulse widths, and underdamped discharge characteristics, leading to patient discomfort and reduced therapeutic efficacy due to activation of pain receptors and inconsistent shock wave generation.
Innovation Solution
An electrohydraulic shock wave generator with a high-voltage, low-capacitance discharge system, low-resistance wiring, and diode suppression network to produce rapid, narrow pulses with critically-damped waveforms, minimizing pain perception and enhancing cellular mechanotransduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional electrohydraulic generators use standard discharge circuits, then the system is simple to operate, but the rise time is slow and pulse width is broad causing patient discomfort
Solution Approach 1:
The patent introduces a damping resistor as an intermediary element in the discharge circuit. This resistor is connected in series with the capacitor and discharge electrode, acting as a mediator that controls the discharge current waveform. By selecting an appropriate resistance value, the circuit achieves critically damped discharge characteristics, producing rapid rise time and narrow pulse width without requiring complex active control circuits.
Solution Approach 2:
The patent changes the electrical parameters of the discharge circuit by introducing a specific damping resistor value. This parameter modification transforms the discharge characteristics from underdamped (oscillatory) to critically damped (non-oscillatory with rapid rise), achieving fast pulse generation while maintaining circuit simplicity. The resistor value is selected to optimize the time constant of the RC circuit.
2Object-affected harmful factors
If conventional generators produce broad pulses, then the discharge energy is distributed over time, but pain receptors are activated and therapeutic efficacy is reduced
Solution Approach 1:
The damping resistor serves as a waveform-shaping intermediary that converts the capacitor's natural exponential discharge into a critically damped pulse. This intermediary element limits the pulse width by controlling the discharge current decay rate, ensuring the mechanical stimulus duration is too brief to activate pain receptors while delivering sufficient peak power for therapeutic effect.
Solution Approach 2:
The circuit design incorporates preliminary damping resistance to prevent oscillatory discharge before it occurs. By pre-configuring the RC time constant to achieve critical damping, the system avoids the harmful oscillatory current flow and prolonged pulse width that would activate nociceptors, thereby preventing patient discomfort before it can occur.
3Reliability
If generators use underdamped discharge characteristics, then the circuit is simple, but oscillatory current flow causes pulse broadening and electrode erosion
Solution Approach 1:
The damping resistor acts as a stabilizing intermediary that converts underdamped oscillatory discharge into critically damped non-oscillatory discharge. This simple passive component eliminates current oscillations and associated electrode erosion while maintaining circuit simplicity, providing reliable and consistent shock wave generation without complex active control mechanisms.
Solution Approach 2:
The damping resistor provides beforehand cushioning against oscillatory discharge by pre-configuring the circuit's damping ratio. This passive damping element absorbs excess energy that would otherwise cause oscillations, protecting the electrodes from erosion and ensuring consistent shock wave output from the first discharge without requiring complex protection circuits.
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 improved generator achieves rapid rise times and narrow pulse widths, effectively bypassing pain receptors and optimizing therapeutic outcomes by reducing patient discomfort while maintaining clinical efficacy through enhanced strain rates in biological tissues.
Implementation Method 1
These devices generate shock waves by creating high-voltage electrical discharges between electrodes positioned in a liquid medium
Implementation Method 2
a diode suppression network prevents reverse voltage transients and suppresses discharge oscillations
Data Source
AI summary
An electrohydraulic shock wave generator includes a capacitor configured to store electrical energy and a discharge circuit configured to discharge the capacitor through an electrode assembly positioned in an electrically conductive medium to generate shock waves. A diode suppression network is positioned within the discharge circuit and configured to prevent reverse voltage transients and suppress discharge oscillations. The diode suppression network converts underdamped oscillatory discharge into critically damped discharge waveform to produce shock waves having narrow pulse widths. The generator may include low-resistance discharge circuits with conductors having greater cross-sectional areas and total circuit resistance of less than 0.025 ohms. The capacitor may have a capacitance of 25 nanofarads or less and store electrical energy at voltages between 15 kilovolts and 60 kilovolts. The critically-damped discharge waveform produces shock waves having rapid rise times that minimize activation of pain-sensing nerve fibers during therapeutic treatment.