Delay-Line Temperature Sensing by Clock Pulse Stretch Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing temperature sensors, particularly voltage domain and some time domain sensors, are complex and require additional circuitry for clock generation and frequency/period measurement, making them less efficient for temperature determination.
Innovation Solution
A method and apparatus that utilize a temperature-dependent measurement inverter to stretch a clock pulse through a delay line, allowing temperature determination based on the number of cycles required to equal or exceed the pulse period, without relying on frequency or period measurement circuits and internal clock generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage domain temperature sensors are used to convert temperature to voltage, then temperature measurement can be achieved, but the circuit complexity increases
Solution Approach 1:
The patent replaces voltage domain measurement with time domain measurement. Instead of measuring temperature-dependent voltage changes, the invention measures temperature-dependent time intervals. A reference signal with a fixed period is compared against a temperature-dependent signal, and the temperature is determined by measuring the time relationship between these signals. This substitution of measurement domain simplifies the circuit by eliminating complex voltage measurement and conversion circuitry.
2Measurement precision
If time domain temperature sensors are used with frequency and period measurement circuits, then temperature can be determined, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for complex frequency and period measurement circuits from the temperature sensing system. Instead of using these complex circuits to measure the frequency or period of a temperature-dependent oscillator, the invention directly compares the phase or time relationship between a reference signal and a temperature-dependent signal. This extraction of unnecessary complex components achieves temperature determination with simpler circuitry.
Solution Approach 2:
The patent uses a reference signal that is a simplified copy or analog of the temperature-dependent signal, with which it can be directly compared. Rather than building complex measurement circuits to analyze the temperature signal's frequency characteristics, the invention creates a reference signal with known characteristics and directly compares the two signals in the time domain, achieving temperature measurement without complex analysis circuits.
3Measurement precision
If additional clock generation circuitry is added for temperature-to-digital conversion, then conversion accuracy improves, but the overall device complexity increases
Solution Approach 1:
The patent makes the temperature-dependent signal serve multiple functions simultaneously. The same signal that carries temperature information is also used as the basis for time-to-digital conversion without requiring a separate clock generation circuit. The reference signal and the temperature-dependent signal are directly compared, and the time relationship between them provides both the temperature measurement and the digital conversion function in a unified manner, eliminating the need for additional dedicated clock generation 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
This approach simplifies temperature sensing by eliminating the need for complex clock generation circuitry and frequency/period measurement, resulting in a more efficient and less complex temperature determination process.
Implementation Method 1
The temperature dependent measurement invertor has a different response time to transition from a high output to a low output then to transition from the low output to the high output
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A method, apparatus and computer program product are provided to reliably determine a temperature, such as in the time domain. In this regard, an apparatus includes a delay line having a temperature dependent measurement invertor configured to stretch a clock pulse that was generated by an oscillating circuit during circulation of the clock pulse through the delay line. The amount by which the clock pulse is stretched during a cycle about the delay line is dependent upon temperature. The apparatus also includes detection circuitry configured to detect an instance in which clock pulse has been stretched so as to equal or exceed a period of the clock pulse. The apparatus further includes processing circuitry configured to determine the temperature based at least in part upon a number of cycles completed to stretch the clock pulse so as to equal or exceed the period of the clock pulse.