Electrosurgical Square-Wave Generator for Tissue Sealing Control
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Solution Overview
Problem
Existing electrosurgical systems using sinusoidal waveforms are inefficient due to power loss in linear components and require complex sensing hardware to accurately calculate tissue impedance, and have higher peak voltages that can negatively impact tissue treatments.
Innovation Solution
A square wave generator for electrosurgical devices that includes a voltage source, comparator, sensors, and a controller to output energy in the form of square waves, allowing for simplified monitoring of peak voltage or current and reducing the need for large resonant components and complex signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sinusoidal waveforms are used to deliver energy for tissue treatment, then excellent tissue sealing performance can be achieved, but power loss occurs due to linear components and complex sensing hardware is required to calculate RMS voltage and current
Solution Approach 1:
The patent changes the waveform parameter from sinusoidal to square wave. This parameter change eliminates the need for linear components (resistors, capacitors, inductors) that cause power loss in sinusoidal waveforms, while maintaining effective tissue sealing performance through the square wave's unique electrical characteristics
2Reliability
If sinusoidal waveforms are used, then tissue sealing can be achieved, but complicated sensing hardware and signal processing are required to accurately calculate RMS voltage and current
Solution Approach 1:
By changing from sinusoidal to square wave, the patent simplifies the measurement parameter. Square waves have constant amplitude throughout their cycle, allowing impedance calculation using simple peak voltage and current measurements rather than complex RMS calculations, thereby eliminating complicated sensing hardware and signal processing requirements
3Power
If sinusoidal waveforms are used, then energy delivery can be achieved, but peak voltage is 1.414 times the RMS voltage which may have negative impact on tissue treatments
Solution Approach 1:
The patent changes the waveform parameter from sinusoidal to square wave, which has a crest factor of 1.0 (peak voltage equals RMS voltage) compared to sinusoidal waveforms' 1.414 crest factor. This parameter change maintains effective energy delivery while eliminating the excessive peak voltage that causes arcing and negative tissue treatment effects
4Shape
If resonant amplifier topologies are used to generate sinusoidal waveforms, then waveform shaping can be achieved, but large resonant components are required
Solution Approach 1:
By changing from sinusoidal to square wave generation, the patent eliminates the need for large resonant components (inductors and capacitors) required for waveform shaping. Square waves can be generated efficiently using switching amplifiers with minimal resonant components, dramatically reducing the volume of stationary components in the system
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 square wave generator achieves efficient energy delivery with reduced component count, smaller size, and lower peak voltages, enhancing electrosurgical performance and reducing the risk of arcing, while enabling accurate impedance monitoring without complex sensing hardware.
Implementation Method 1
a comparator operatively coupled to the voltage source and configured to output energy in the form of a square wave
Implementation Method 2
at least one sensor configured to sense an operational parameter of the energy outputted from the comparator
Implementation Method 3
a controller adapted to receive the at least one sensor signal and in response thereto control the voltage source
Data Source
AI summary
A square wave generator suitable for use with an electrosurgical device is provided. The square wave generator includes a voltage source configured to output a waveform and a comparator operatively coupled to the voltage source and configured to output energy in the form of a square wave. The generator may also include at least one sensor configured to sense an operational parameter of the energy outputted from the comparator and to provide a sensor signal corresponding thereto and a controller adapted to receive the at least one sensor signal and in response thereto control the voltage source.