Surgical Generator Overcurrent Mitigation via PWM Duty Cycle Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Surgical generators face challenges in mitigating overcurrent conditions during energy-based tissue treatment, which can lead to tissue damage and inefficiencies in procedures like electrosurgery and microwave surgery.
Innovation Solution
A method and system that includes a pulse-width modulation signal control system, overcurrent detection, and an interrupt circuit to disable the radio frequency output stage during overcurrent conditions, incrementally decrease the duty cycle, and maintain a low duty cycle for a predetermined time before re-enabling the output stage, ensuring safe and controlled energy delivery to tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high power radio frequency signal is supplied to tissue during electrosurgery, then surgical effectiveness is improved, but overcurrent conditions occur causing tissue damage
Solution Approach 1:
The patent implements preliminary protective actions by establishing overcurrent detection mechanisms and interrupt circuits before harmful effects occur. The system continuously monitors current levels and prepares interrupt pathways in advance, enabling rapid response when overcurrent conditions are detected, thus preventing tissue damage before it happens.
Solution Approach 2:
The patent employs feedback control through overcurrent detection circuits that continuously monitor the radio frequency signal parameters. When overcurrent conditions are detected, the system provides feedback to the control circuit, which then adjusts or interrupts the power supply to maintain safe operating levels, preventing tissue damage while preserving surgical effectiveness.
2Object-affected harmful factors
If interrupt circuit disables radio frequency output stage during overcurrent, then tissue damage is prevented, but surgical procedure efficiency decreases
Solution Approach 1:
The patent implements periodic monitoring of current levels through the overcurrent detection circuit, allowing the system to operate at full power during normal conditions while periodically checking for overcurrent situations. This periodic detection enables the system to maintain high efficiency during safe operation while providing continuous protection against tissue damage.
Solution Approach 2:
The patent employs dynamic control where the radio frequency output stage can transition between full power operation and interrupted/disabled states based on real-time current conditions. The system dynamically adjusts its operation level, maintaining maximum efficiency when safe and providing immediate protection when needed, rather than operating at reduced power continuously.
3Object-affected harmful factors
If duty cycle is continuously reduced to mitigate overcurrent, then tissue safety is improved, but energy delivery consistency deteriorates
Solution Approach 1:
The patent applies preliminary anti-action by implementing interrupt circuits that prevent overcurrent conditions from developing in the first place. Rather than continuously reducing duty cycle as a reactive measure, the system establishes protective barriers and detection mechanisms that anticipate and prevent harmful current levels, maintaining both tissue safety and energy delivery consistency.
Solution Approach 2:
The patent maintains continuity of useful action by allowing the radio frequency output to operate continuously at optimal power levels during normal conditions. The overcurrent protection mechanisms operate in parallel without interfering with normal operation, ensuring that energy delivery remains consistent and effective while tissue safety is maintained through selective interruption only when necessary.
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
Effectively mitigates overcurrent conditions, preventing tissue damage and ensuring consistent energy delivery, thereby enhancing the safety and efficacy of surgical procedures.
Implementation Method 1
supplying a pulse-width modulation signal to a power supply; generating within the power supply a power signal in response to the pulse-width modulation signal
Implementation Method 2
generating within the radio frequency output stage a radio frequency signal from the power signal
Implementation Method 3
application of high radio frequency electrical current, e.g., electrosurgical energy, to a surgical site to cut, ablate, coagulate, or seal tissue
Implementation Method 4
Heating is caused by high current densities that directly depend on the surface area
Implementation Method 5
In the monopole and dipole antenna probes, microwave energy generally radiates perpendicularly away from the axis of the conductor
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A surgical generator and related method for mitigating overcurrent conditions are provided. The surgical generator includes a power supply, a radio frequency output stage, an overcurrent detection circuit in operative communication with an interrupt circuit, and a processor. The power supply generates a power signal and supplies the power signal to the radio frequency output stage. The radio frequency output stage generates a radio frequency signal from the power signal. The overcurrent detection circuit detects an overcurrent of the power signal and/or an overcurrent of the radio frequency signal. The interrupt circuit provides an interrupt signal in response to a detected overcurrent. The processor receives the interrupt signal and supplies a pulse-width modulation signal to the power supply and incrementally decreases the duty cycle of the pulse-width modulation signal in response to the interrupt signal. The radio frequency output stage may be disabled in response to the detected overcurrent.