Electrosurgical Switch Detection via H-Bridge Measurement Current
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Solution Overview
Problem
Existing electrosurgical instrument monitoring systems require complex circuitry to detect activation of instrument switching means, particularly due to the need for negative voltages and currents, which increases circuit complexity and requires precise calibration of analog optocouplers.
Innovation Solution
A device with a power converter and control device generates a measurement current using controllable switching means, allowing detection of instrument switching means activation without negative voltages by using a H-bridge topology and different conducting directions for switches, simplifying circuitry and eliminating the need for negative voltage components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a common connection line is used to connect instrument switching means to the generator, then the number of connection lines is reduced, but circuit complexity increases due to the need for negative voltages and currents for detection
Solution Approach 1:
The patent changes the electrical parameters by using unipolar alternating voltage instead of bipolar voltage, and uses duty cycle modulation (ratio of active phase to total period) to encode different switching means activations, eliminating the need for negative voltages while maintaining detection capability
Solution Approach 2:
The patent introduces an intermediary evaluation device that processes the current flows through the common connection line during different active phases, using the timing and characteristics of current flow to distinguish which switching means was activated without requiring separate lines or negative voltages
2Measurement precision
If negative voltages are used for detecting switching means activation, then detection accuracy is improved, but manufacturing precision requirements increase due to calibration needs
Solution Approach 1:
The patent eliminates negative voltages entirely by using unipolar alternating voltage with duty cycle modulation, removing the source of calibration complexity while maintaining detection accuracy through temporal encoding of switching states
Solution Approach 2:
The patent replaces the mechanical/electrical calibration system (analog optocouplers requiring precise adjustment) with a digital evaluation system that determines switching states based on timing and duty cycle analysis, eliminating the need for manual calibration
3Ease of operation
If analog optocouplers are used for evaluation, then detection capability is achieved, but device complexity increases due to precise adjustment requirements
Solution Approach 1:
The patent replaces analog optocoupler-based evaluation with a digital evaluation device that analyzes current flow timing and duty cycle, eliminating the need for analog component adjustment and calibration while maintaining detection functionality
Solution Approach 2:
The evaluation device automatically determines which switching means was activated by analyzing the timing characteristics of current flow during different active phases, without requiring manual calibration or adjustment, making the system self-configuring
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
This solution reduces circuit complexity, avoids the use of negative voltages, and enables accurate detection of instrument switching means activation with less circuitry, improving the reliability and efficiency of electrosurgical instrument monitoring.
Implementation Method 1
a first measurement current establishes along a first current path through the first controllable switching means and through the first instrument switching means when the first controllable switching means and the first instrument switching means are electrically conductive
Data Source
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AI summary
The present invention relates to a device (100) for detecting activation of an instrument switching means (SW1, SW2) of an electrosurgical instrument (20), comprising: a power converter (110) for generating an electrical measurement current (IM), wherein the power converter (110) being configured with at least a first and a second controllable switching means (M1, M2, M3, M4);a control device (120) for actuating the controllable switching means (M1, M2, M3, M4) of the power converter (110), at least first and second instrument switching means (SW1, SW2), wherein the first and second instrument switching means (SW1, SW2) being electrically connected to the power converter (110), and an evaluation device (130) for evaluating the generated measurement current, characterized in that the power converter (110) and the instrument switching means (SW1, SW2) are connected in the way that a first measurement current (IM1) establishes along a first current path (140) through the first controllable switching means (M1) and through the first instrument switching means (SW1) when the first controllable switching means (M1) and the first instrument switching means (SW1) are electrically conductive, and no measurement current (IM) establishes when the first controllable switching means (M1) and the second instrument switching means (SW2) are electrically conductive, and a second measurement current (IM2 ) establishes along a second current path (150) through the second controllable switching means (M2) and through the second instrument switching means (SW2) when the second controllable switching means (M2) and the second instrument switching means (SW2) are electrically conductive, and no measurement current (IM ) establishes when the second controllable switching means (M2) and the first instrument switching means (SW1) are electrically conductive, and wherein the evaluation device (130) is adapted to detect whether the generated measurement current (IM , IM1 , IM2 ) is established along the first current path (140) or along the second current path (150).