Injection-Locked Sensor Interface for High-Temperature Precision

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Solution Overview

Problem

Sensors in hostile environments face operational failures due to parameter variations such as extreme temperatures and radiation, leading to increased current leakage and precision issues in existing sensor interfaces.

Innovation Solution

An interface circuit utilizing injection-locked oscillators, where the free-running oscillation frequency is controlled by sensor signals, generating phase-shifted output signals based on synchronization signals, and a calibration circuit adjusts these frequencies to maintain accuracy, with a digital output generated from phase differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sensors are placed in hostile environments with extreme temperatures, then sensor coverage and monitoring capability are improved, but current leakage increases exponentially leading to circuit failure

Engineering Contradiction:

Improvesensor operation reliabilityVSAvoidcurrent leakage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces traditional voltage-based sensing circuits with a frequency-based injection-locked oscillator system. The sensor signal modulates the oscillation frequency rather than relying on voltage levels, making the system immune to temperature-induced current leakage and allowing reliable operation in hostile environments up to 250°C

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transforms the sensor output parameter from voltage to frequency modulation. The injection-locked oscillator converts the sensor signal into frequency variations that are then demodulated to recover the original sensor data, eliminating the harmful effects of temperature on voltage-based circuits

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If conventional sensor interfaces are used in high temperature environments, then temperature monitoring is enabled, but measurement precision deteriorates due to parameter variations

Engineering Contradiction:

Improvesensor output precisionVSAvoidenvironmental temperature

Core Design Contradiction:

Measurement precisionVSTemperature

Solution Approach 1:

The patent substitutes voltage-based measurement with frequency-based measurement using injection-locked oscillators. Since frequency is less sensitive to temperature variations than voltage, the system maintains high measurement precision even at temperatures up to 250°C where conventional interfaces fail

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a feedback mechanism where the output of one injection-locked oscillator is used to control the frequency of another, creating a self-correcting system that maintains measurement precision by compensating for environmental parameter variations through phase comparison

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If robust sensor interfaces are designed for hostile environments, then environmental tolerance is improved, but device complexity increases

Engineering Contradiction:

Improveenvironmental adaptabilityVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses injection-locked oscillators that serve multiple functions: they act as frequency modulators, frequency dividers, and phase detectors simultaneously. This multi-functionality reduces the need for separate circuit components, maintaining relatively simple device architecture while achieving high environmental adaptability

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 provides robustness against environmental parameter variations, ensuring precise sensor output with low power consumption and reduced sensitivity to temperature changes, enhancing sensor performance in harsh conditions.

Implementation Method 1

a first injection-locked oscillator having: a first input coupled to a sensor, a free-running oscillation frequency of the first injection-locked oscillator being controlled by a signal from the sensor; and a second input coupled to receive a synchronization signal at a reference frequency, the first injection-locked oscillator being adapted to generate an output signal at said reference frequency, the output signal being phase shifted with respect to the synchronization signal as a function of the signal from the sensor

Methodology Applied

Scientific EffectInjection locking:

Data Source

PatentUS10436666B2Sensor interface for hostile environments

Publication Date: 2019.10.08 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

An interface circuit for a sensor including: a first injection-locked oscillator having: a first input coupled to a sensor, a free-running oscillation frequency of the first injection-locked oscillator being controlled by a signal from the sensor; and a second input coupled to receive a synchronization signal at a reference frequency, the first injection-locked oscillator being adapted to generate an output signal at said reference frequency, the output signal being phase shifted with respect to the synchronization signal as a function of the signal from the sensor.