Ring Oscillator Thermal Sensor With PTAT-CTAT Linearity Control
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Solution Overview
Problem
Existing thermal sensors face challenges in providing reliable temperature measurements across extreme climates due to overstress issues and non-linear responses, which affect their accuracy and sensitivity.
Innovation Solution
A thermal sensor utilizing a ring oscillator with a temperature-sensitive resistance circuit that switches between two modes, employing proportional-to-absolute-temperature and complementary-to-absolute-temperature resistors to enhance the temperature coefficient and improve linearity, while suppressing leakage through voltage control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional thermal sensor is used to measure temperature in extreme climates, then the device can operate in various environments, but the measurement accuracy deteriorates due to overstress issues and non-linear responses
Solution Approach 1:
The patent employs a ring oscillator whose oscillation frequency dynamically changes with temperature variations. The oscillator uses temperature-sensitive resistors (PTAT and CTAT) that exhibit dynamic resistance changes with temperature, allowing the system to adaptively track temperature across extreme ranges while maintaining measurement linearity and accuracy
Solution Approach 2:
The patent changes the operating parameters by using two different resistor configurations (PTAT and CTAT) with opposite temperature coefficients. By switching between these different parameter states and combining their effects, the system achieves enhanced temperature coefficient and improved linearity, resolving the contradiction between reliability and precision in extreme climates
2Measurement precision
If the ring oscillator oscillation amplitude is increased to improve signal detection, then the sensitivity improves, but the overstress problem worsens causing unreliable operation
Solution Approach 1:
The patent introduces capacitors as intermediary energy storage elements in the ring oscillator circuit. These capacitors buffer and smooth the oscillation signals, allowing the oscillator to maintain reliable operation at reduced amplitudes while still providing sufficient signal strength for accurate temperature detection, thus resolving the contradiction between sensitivity and reliability
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 a high-linearity thermal sensor with enhanced temperature coefficient, ensuring accurate temperature measurement by eliminating non-ideal factors and maintaining oscillation within a controlled range, thereby improving sensitivity and reliability.
Implementation Method 1
The ring oscillator oscillates based on a resistance-and-capacitance (RC) coefficient
Implementation Method 2
the proportional-to-absolute-temperature resistor, which corresponds to a positive temperature coefficient
Implementation Method 3
the complementary-to-absolute-temperature resistor which corresponds to a negative temperature coefficient, and is operative to remove higher-order non-ideal factors from the evaluated result of the temperature information, T
Data Source
AI summary
A thermal sensor using a ring oscillator is shown. The ring oscillator oscillates based on a resistance-and-capacitance (RC) coefficient. The ring oscillator includes a temperature-sensitive resistance circuit. The resistance factor of the resistance-and-capacitance coefficient depends on the temperature-sensitive resistance circuit. The thermal sensor evaluates temperature information, T, based on the oscillation of the ring oscillator.