Waveform Shaping Circuit Fault Detection in Tissue Signal Generators
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Solution Overview
Problem
Signal generators used in pulsed electric field therapy face reliability concerns due to the failure of solid state switches under high voltage and current conditions, leading to inconsistent treatment signals.
Innovation Solution
A signal generator design incorporating capacitors, a waveform shaping circuit, and a controller that performs fault tests to ensure proper operation of switches, including a voltage sense circuit and a current sense circuit to detect stuck switches, thereby preventing failures and ensuring reliable treatment signal generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If solid state switches are used in the signal generator to generate pulsed electric field signals, then the device can deliver high voltage and high current pulses for tissue treatment, but the solid state switches may fail under these extreme conditions leading to reliability concerns
Solution Approach 1:
The system performs preliminary fault tests on the switching network before delivering treatment signals to patients. The controller activates switches in the waveform shaping circuit and monitors their operation to detect potential failures before they occur during actual treatment, preventing unreliable switches from compromising patient safety
Solution Approach 2:
The system continuously monitors the operation of solid state switches through voltage sense circuits and current sense circuits that provide feedback to the controller. This real-time feedback enables the system to detect switch anomalies and prevent further operation of faulty switches, maintaining reliability under high voltage and current conditions
2Reliability
If fault tests are performed on the signal generator to detect switch failures, then the reliability of treatment signal generation is improved, but the complexity of the device increases due to additional sensing circuits and control logic
Solution Approach 1:
The voltage sense circuit and current sense circuit serve multiple functions: they monitor switch operation during fault tests, detect anomalies during treatment signal delivery, and provide data for determining switch health status. This multi-functionality reduces the need for separate dedicated monitoring components, mitigating the increase in device complexity
Solution Approach 2:
The waveform shaping circuit's own switching network is used to perform self-diagnosis through fault tests. The controller activates switches and monitors their behavior using the existing voltage and current sensing capabilities of the circuit, allowing the system to self-test without requiring entirely separate diagnostic equipment
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 enhances the reliability of signal generators by identifying and addressing switch faults, ensuring consistent and effective treatment signals for tissue modification systems, reducing the risk of equipment failure and improving treatment efficacy.
Implementation Method 1
one or more capacitors coupled between a high voltage rail and a low voltage rail and configured to store energy
Implementation Method 2
The voltage sense circuit is configured to sense a voltage stored on the one or more capacitors
Implementation Method 3
The current sense circuit is configured to sense current having a magnitude that is indicative of a magnitude of current flowing through a pair of the switches
Data Source
AI summary
Embodiments described herein relate to signal generators, systems including signal generators, and related methods. A signal generator includes capacitor(s) to store energy used to generate a treatment signal. The signal generator also includes a waveform shaping circuit, a controller, a voltage sense circuit, and a current sense circuit. The waveform shaping circuit is coupled to the capacitor(s) and includes first, second, third, and fourth switches, each of which is configured to be selectively turned ON and OFF, to allow current to pass through the switch when turned ON, and to prevent current from passing through the switch when turned OFF. The controller selectively controls the switches in order to generate the treatment signal. The controller also selectively controls the switches in order to perform certain fault tests, which rely on voltages sensed by the voltage sense circuit and currents sensed by the current sense circuit.