Shared-Wire Sensor Circuit for High- and Low-Voltage Guidewires
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Solution Overview
Problem
Integrating high voltage and low voltage sensors into a minimally invasive medical device like a guidewire or catheter is challenging due to limited space, and existing solutions require additional control wires or fail to protect low voltage sensors from high voltage signals, especially when using bi-polar pulses.
Innovation Solution
A sensor device with a shorting circuit that uses frequency and voltage amplitude characteristics to automatically select and protect a first sensor from signals associated with a second sensor, allowing both to be driven by a shared pair of wires, using a shorting switch and frequency-dependent filter circuit to prevent exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high voltage and low voltage sensors are integrated into a single guidewire, then sensing functionality is improved, but the risk of low voltage sensor breakdown from high voltage signals increases
Solution Approach 1:
The shorting switch is activated in advance before high voltage bipolar pulses are applied to the ultrasound transducer. This preliminary action ensures the low voltage sensor is protected from high voltage breakdown before the harmful voltage can affect it, while still allowing the high voltage sensor to function.
Solution Approach 2:
The shorting switch acts as an intermediary protective element between the high voltage ultrasound transducer and the low voltage sensor. It provides a controlled path for high voltage signals while isolating the low voltage sensor, enabling both sensors to coexist on the same guidewire without interference or damage.
2Reliability
If a shorting switch is added to protect the low voltage sensor, then sensor protection is improved, but device complexity increases
Solution Approach 1:
The shorting switch is controlled automatically by a control circuit that detects the presence of bipolar pulses. The system monitors its own operating conditions and activates protection only when needed, without requiring external control or adding complex manual switching mechanisms.
Solution Approach 2:
The control circuit detects changes in voltage parameters (bipolar pulse characteristics) to trigger the shorting switch. By monitoring voltage polarity and magnitude changes, the system automatically activates protection only during high voltage ultrasound operation, avoiding unnecessary switching and reducing overall system complexity.
3Adaptability or versatility
If additional control wires are added for sensor switching, then sensor selection capability is improved, but wire count increases
Solution Approach 1:
The existing two wires used for ultrasound transducer operation serve dual purposes: they carry both the high voltage bipolar pulses for the ultrasound sensor and the control signals for the shorting switch. This multi-functionality eliminates the need for separate control wires while maintaining full sensor selection and protection capability.
Solution Approach 2:
The control function for the shorting switch is merged with the existing ultrasound drive circuitry. The same wires that deliver high voltage to the transducer also provide the control signals needed to activate protection, combining multiple functions into a single wire system and minimizing wire count.
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
Enables simultaneous or quasi-simultaneous operation of high voltage and low voltage sensors without additional control wires, ensuring protection and efficient signal processing through automatic sensor selection based on frequency and voltage differences.
Implementation Method 1
a shorting circuit comprising a shorting switch and a frequency-dependent filter circuit for controlling the switching of the shorting switch
Implementation Method 2
the shorting circuit is adapted to short the first sensor based on at least frequency by closing the shorting switch when signals in the second frequency range are present
Data Source
AI summary
A sensor device comprises at least two sensors at the end of a shaft (such as a guidewire or catheter). One sensor uses signals in a first frequency range and a first voltage range and the other sensor uses signals in a second frequency range different to the first frequency range and a second voltage range different to the first voltage range. The first sensor is shorted based on frequency analysis, thereby to prevent the first sensor being exposed to signals associated with the second sensor. This enables the two sensors to be driven by the same shared pair of wires along the shaft, with automatic selection of the suitable sensor.