Electrosurgical Generator RF Output Stage Phase Control
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Solution Overview
Problem
Current electrosurgical generators fail to deliver sufficiently powerful and efficient radiofrequency (RF) energy for prolonged tissue thermal heating during procedures like ablation and coagulation, leading to inefficiencies and limitations in tissue treatment.
Innovation Solution
An electrosurgical generator with an RF output stage featuring two connections to a transformer, each with a switching component and parallel inductor-capacitor resonant circuit, generating 180° phase-shifted half-sinusoidal waveforms that combine to produce a pure sine wave, utilizing a series inductor-capacitor resonant circuit to enhance power delivery and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If current state of the art electrosurgical generators are used to generate RF energy, then tissue treatment can be performed, but the power delivery is insufficient and efficiency is poor
Solution Approach 1:
The RF output stage is segmented into two separate connections, each with its own parallel LC resonant circuit and switching component. This segmentation allows independent optimization of each channel and enables the combination of two half-sinusoidal waveforms to create a complete sine wave, improving overall power delivery and efficiency.
Solution Approach 2:
The switching components in the two connections are cycled between on and off positions at the same frequency but in a 180 degree out-of-phase relationship. This periodic action with precise phase control generates two half-sinusoidal waveforms that combine to form a complete sine wave, enabling efficient RF energy delivery.
2Power
If higher RF power is delivered for prolonged tissue heating, then larger lesions can be created, but heat loss increases and efficiency decreases
Solution Approach 1:
The patent converts the potential harm of heat loss by using resonant LC circuits that minimize energy dissipation. The resonant circuits are designed to operate at specific frequencies where energy is efficiently stored and transferred, converting what would be heat loss into useful RF energy for tissue heating and lesion creation.
Solution Approach 2:
The system changes key parameters including the phase relationship (180 degrees out-of-phase), frequency (predetermined frequency), and circuit configuration (parallel and series LC combinations) to optimize RF power delivery. These parameter changes enable efficient energy transfer and reduce heat loss while maintaining high power output for prolonged tissue heating.
3Loss of energy
If complex RF generation circuits are used to improve power delivery, then efficiency may improve, but device complexity and form factor increase
Solution Approach 1:
The two connections in the RF output stage serve multiple functions: each connection generates a half-sinusoidal waveform, acts as a resonant circuit for efficient energy storage, and contributes to the complete sine wave output. This multi-functionality reduces the need for additional separate components, maintaining efficiency while controlling complexity.
Solution Approach 2:
The patent merges the two half-sinusoidal waveforms from the separate connections into a single complete sine wave output through the transformer. This combining approach consolidates the output stages and simplifies the overall circuit architecture while maintaining the efficiency benefits of the dual resonant circuit design.
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 solution enables efficient generation and delivery of high RF power, reducing heat loss and allowing for larger lesion creation capabilities, such as forming lesions up to 8 cm in diameter, while maintaining high efficiency and minimizing weight and form factor.
Implementation Method 1
a first parallel inductor-capacitor circuit being driven by a first signal at a first predetermined frequency and a second parallel inductor-capacitor inductor-capacitor circuit driven by a second signal at the first predetermined frequency phase shifted 180°
Implementation Method 2
The first and second parallel inductor-capacitor circuits are operably connected to the transformer, such that the first inductor-capacitor circuit generates a positive half sine wave and the second inductor-capacitor circuit generates a 180° phase-shifted positive half sine wave to generate a full sine wave in a secondary winding of the transformer
Implementation Method 3
a series inductor-capacitor resonant circuit operably connected in series with a primary winding of a transformer
Data Source
AI summary
An electrosurgical generator is disclosed. The electrosurgical generator includes a power supply for generating a DC voltage. The electrosurgical generator also includes a first parallel inductor-capacitor circuit being driven by a first signal at a first predetermined frequency and a second parallel inductor-capacitor inductor-capacitor circuit driven by a second signal at the first predetermined frequency phase shifted 180°. The electrosurgical generator further includes a series inductor-capacitor resonant circuit operably connected in series with a primary winding of a transformer. The first and second parallel inductor-capacitor circuits are operably connected to the transformer, such that the first inductor-capacitor circuit generates a positive half sine wave and the second inductor-capacitor circuit generates a 180° phase-shifted positive half sine wave to generate a full sine wave in a secondary winding of the transformer.