Delay-Line Temperature Sensing by Clock Pulse Stretch Detection
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Solution Overview
Problem
Existing temperature sensors, particularly voltage domain and some time domain sensors, are complex and require additional circuitry for temperature measurement, which can complicate industrial and health monitoring applications.
Innovation Solution
A method and apparatus that utilize a temperature-dependent measurement inverter to stretch a clock pulse through a delay line, allowing for temperature determination without relying on frequency or period measurement circuits, and internally generate a clock signal, simplifying the process by counting cycles until the pulse equals or exceeds its period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage domain temperature sensors are used to convert temperature to voltage, then temperature measurement is achieved, but device complexity increases due to additional circuitry requirements
Solution Approach 1:
The patent replaces voltage domain temperature sensing with a time domain approach. Instead of measuring temperature-dependent voltage changes that require complex circuitry, the invention uses a ring oscillator whose oscillation period changes with temperature, converting the measurement to the time domain where simpler detection methods can be applied.
Solution Approach 2:
The patent uses a delay line that creates a time-delayed copy of the clock signal. This delayed version is compared with the original clock signal to generate a measurement output, effectively copying the timing information and using it for temperature determination without requiring complex voltage measurement circuits.
2Measurement precision
If time domain temperature sensors with frequency measurement circuits are used, then temperature measurement is achieved, but device complexity increases due to frequency and period measurement circuits
Solution Approach 1:
The patent extracts only the essential timing information needed for temperature measurement by using a delay line to create a simplified time difference measurement. Instead of implementing full frequency or period measurement circuits, the invention extracts the temperature-dependent time difference between the clock signal and its delayed version, eliminating the need for complex measurement circuits.
Solution Approach 2:
The patent introduces a delay line as an intermediary element between the ring oscillator and the measurement output. This delay line mediates the temperature measurement by creating a time-delayed copy of the clock signal, which when compared with the original, produces a measurement signal that directly reflects temperature without requiring complex frequency or period analysis circuits.
3Measurement precision
If additional clock generation circuitry is added for temperature-to-digital conversion, then temperature measurement is achieved, but device complexity increases
Solution Approach 1:
The patent makes the ring oscillator serve multiple functions: it generates the system clock signal for normal operation and simultaneously serves as the temperature sensing element. The same oscillating circuit provides both timing functionality and temperature measurement, eliminating the need for separate clock generation circuitry dedicated to temperature conversion.
Solution Approach 2:
The ring oscillator is self-sufficient, providing both the clock signal needed for system operation and the temperature-dependent timing information needed for measurement. The system uses its own internal clock signal and the inherent temperature dependence of the oscillator period without requiring external or additional clock generation circuits.
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 results in a less complex temperature measurement system that is applicable across various applications, including industrial and health monitoring, without the need for additional clock generation circuitry, providing reliable temperature determination in the time domain.
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
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.