Temperature Sensing Circuit with Pulse Width Expansion
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Solution Overview
Problem
Conventional temperature sensing circuits face challenges in accurately measuring temperature changes due to variations in delay unit values during fabrication, leading to increased circuit area requirements for enhanced sensitivity.
Innovation Solution
A temperature sensing circuit design that includes a signal generation unit with a delay line, a pulse width expansion unit using T flip-flops to expand the pulse width of the source signal, and a control unit to adjust the number of activated delay units, allowing for reduced circuit area while maintaining sensitivity by compensating for fabrication process variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of delay units is increased to enhance temperature sensing sensitivity, then the measurement precision is improved, but the circuit area increases
Solution Approach 1:
The patent implements a dynamic calibration mechanism where the control unit adjusts the number of activated delay units based on feedback from pulse width comparisons. This dynamic adjustment allows the system to optimize sensitivity for different temperature ranges without requiring a fixed large number of delay units, thereby reducing the overall circuit area while maintaining measurement precision.
Solution Approach 2:
The patent changes the operational parameters of the delay units through calibration codes that adjust the number of activated units. By dynamically changing the delay parameter based on temperature conditions, the system achieves high sensitivity without needing a large static number of delay units, thus resolving the contradiction between measurement precision and circuit area.
2Measurement precision
If the number of delay units is increased to accurately measure temperature changes, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent segments the delay units into multiple groups that can be independently activated or deactivated through calibration codes. This segmentation allows the control unit to selectively activate only the necessary number of delay units for accurate measurement, reducing the overall device complexity while maintaining measurement precision through selective activation rather than requiring all units to be permanently configured.
3Measurement precision
If calibration operation is performed to compensate for fabrication process variations, then the measurement precision is improved, but the loss of time increases
Solution Approach 1:
The patent performs calibration operations preliminarily to establish optimal delay unit activation patterns before actual temperature sensing begins. By pre-calibrating the system and storing calibration codes, the patent eliminates the need for repeated calibration during operation, thus improving measurement precision while minimizing time loss through one-time preliminary calibration rather than continuous calibration.
Data Source
AI summary
A temperature sensing circuit includes a signal generation unit including a delay line and generating a source signal with a pulse width corresponding to a delay value of the delay line, a pulse width expansion unit configured to generate a comparison signal by expanding a pulse width of the source signal, and a change detection unit configured to sense a temperature change using a difference between the pulse widths of the comparison signal and a reference signal.