Calibration Techniques for Temperature Sensors
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Solution Overview
Problem
Conventional calibration techniques for temperature sensors in modern circuit architectures require multiple temperature measurements, leading to area deficiencies and increased costs due to the need for multiple temperature sensors and lengthy stabilization times.
Innovation Solution
The proposed solution employs a pseudo two-point calibration method, which exploits the correlation between the frequency of a ring oscillator and its temperature slope, allowing for a precise temperature measurement with a single point calibration, thereby reducing costs and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration techniques are used with multiple temperature sensors and multiple temperature measurements, then measurement precision is improved, but area consumption increases and device complexity increases
Solution Approach 1:
The patent combines multiple temperature measurement functions into a single temperature sensor by using multiple ring oscillators that share the same sensor. The first ring oscillator provides a frequency output for temperature measurement, while the second ring oscillator provides a slope measurement that correlates to temperature. This merging approach achieves multi-point calibration precision without requiring multiple separate temperature sensors, thereby reducing circuit area consumption.
Solution Approach 2:
The single temperature sensor serves multiple functions by being used with different ring oscillators that have different characteristics. The sensor measures both the frequency of the first ring oscillator (which correlates to temperature) and the slope of the second ring oscillator (which also correlates to temperature). This multi-functionality allows one sensor to replace what would traditionally require multiple sensors, reducing both area and complexity.
2Measurement precision
If conventional calibration techniques are used with multiple temperature sensors, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple measurement functions into a unified system where a single temperature sensor works with multiple ring oscillators. The processing unit receives both frequency and slope measurements from the different oscillators and combines them to achieve accurate temperature determination. This integration reduces device complexity compared to managing multiple independent temperature sensors and their separate calibration pathways.
Solution Approach 2:
The ring oscillators act as intermediaries that translate temperature sensor outputs into measurable frequency and slope signals. By using the oscillators as mediators, the system can extract multiple temperature-related parameters from a single sensor without requiring direct complex processing of multiple sensor inputs, thereby simplifying the overall device architecture.
3Measurement precision
If multiple temperature measurements are performed at different temperatures, then measurement precision is improved, but time consumption increases
Solution Approach 1:
The patent performs preliminary characterization of the ring oscillators to establish the correlation between slope and temperature. Once this correlation is established, the system can use slope measurements from subsequent single-point measurements to accurately determine temperature without requiring lengthy stabilization periods at multiple temperature points. This preliminary action enables faster, single-point calibration while maintaining precision.
Solution Approach 2:
The patent changes the measurement parameter from requiring multiple temperature points to using frequency and slope measurements at a single temperature point. By measuring the slope of the ring oscillator frequency with respect to temperature and using the established correlation, the system achieves accurate temperature measurement without the time-consuming process of stabilizing at multiple different temperatures.
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
This approach enables efficient and precise temperature measurement in circuit applications, reducing the need for multiple temperature sensors and minimizing stabilization time, thus improving calibration efficiency and reducing costs.
Implementation Method 1
The frequency of this RO is proportional to temperature
Implementation Method 2
the frequency of a RO is correlated with its slope with respect to temperature
Data Source
AI summary
Various implementations described herein are directed to a method that acquires operating frequencies for a first set of ring oscillators disposed in a first integrated circuit, determines one or more first coefficients and a first constant for each ring oscillator in the first set, and determines a correlation between each of the first coefficients and the first constant. Also, the method may acquire a single operating frequency for each of a second set of ring oscillators in a second integrated circuit at a single pre-determined temperature so as to determine a second constant, predict one or more second coefficients for each ring oscillator in the second set based on the second constant and the correlation, and derive a temperature dependence based on the single operating frequency using the one or more second coefficients and the second constant for each of the second set of ring oscillators.