Shared-Wire Remote Sensor Circuit for High-Voltage Isolation
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Solution Overview
Problem
Integrating high voltage and low voltage sensors in minimally invasive medical devices like guidewires and catheters is challenging due to the limited space and the need to protect low voltage sensors from high voltage signals without requiring additional control wires.
Innovation Solution
A sensor device with a shorting circuit and frequency-dependent filter that automatically selects and protects the low voltage sensor by shorting it when high voltage signals are present, using a shared pair of electrical wires by distinguishing between signal frequencies and voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high voltage and low voltage sensors are integrated in 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 signals are applied to protect the low voltage sensor. The control circuit detects the presence of high voltage signals and preemptively closes the shorting switch to create a protective short circuit path, preventing the high voltage from reaching and damaging the low voltage sensor.
Solution Approach 2:
The shorting switch acts as an intermediary protective element between the high voltage sensor signals and the low voltage sensor. When activated, it provides an alternative low-impedance path that mediates and redirects the high voltage signals away from the vulnerable low voltage sensor, thereby protecting it from breakdown.
2Reliability
If separate control wires are added for each sensor, then sensor control and protection is improved, but the wire count and device complexity increases
Solution Approach 1:
The shared pair of wires serves multiple functions: they provide power and signal transmission for both the high voltage sensor and the low voltage sensor, and they enable the control circuit to detect high voltage signal presence for activating the shorting switch. This multi-functionality eliminates the need for separate dedicated control wires for each sensor.
Solution Approach 2:
The control functions for both sensors are merged into a single control circuit that operates using the shared wire pair. The circuit integrates signal detection, switch control, and sensor operation into one unified system that manages both high voltage and low voltage sensors without requiring additional separate wiring.
3Reliability
If a shorting switch is added to protect the low voltage sensor, then sensor protection is improved, but the device complexity increases
Solution Approach 1:
The control circuit automatically detects the presence of high voltage signals and self-activates the shorting switch without requiring external control inputs. The system monitors the shared wire pair for high voltage conditions and autonomously implements protection by closing the shorting switch, thereby simplifying the overall control architecture.
Solution Approach 2:
The shorting switch serves as a simple intermediary protective component that adds minimal complexity to the circuit. It provides a straightforward binary state (open or closed) controlled by the existing circuit, offering effective protection without requiring complex control logic or additional circuitry.
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 sequential operation of high voltage and low voltage sensors using a shared pair of wires, ensuring the low voltage sensor is protected from high voltage signals, simplifying the integration and operation in minimally invasive medical devices.
Implementation Method 1
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 frequency by closing the shorting switch
Data Source
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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.