Dual-Oscillator Temperature Sensing With Sigma-Delta Bitstream Output
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Solution Overview
Problem
Existing temperature sensors in integrated circuits lack robustness and accuracy, particularly in providing scalable and fully digital temperature information for effective thermal management and calibration of oscillators.
Innovation Solution
A temperature sensor utilizing two oscillators with different temperature dependencies, coupled with a time domain sigma-delta modulator, generates a bitstream indicative of temperature through selective forwarding of oscillation signals and weighted up/down counting, enabling accurate digital temperature representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage domain signals with predetermined temperature dependency are used, then temperature measurement function is achieved, but robustness and accuracy are insufficient
Solution Approach 1:
The patent replaces voltage domain signals with time domain signals generated by oscillators. The oscillators convert temperature-dependent voltage signals into frequency-domain clock signals, which are then processed by digital circuits. This substitution of signal domain (from voltage to time/frequency) improves both robustness and measurement accuracy while enabling full digital integration.
2Ease of manufacture
If fully digital circuit components are used for integration, then scalability and monolithic integration are improved, but temperature measurement accuracy may be compromised
Solution Approach 1:
The patent introduces oscillators as intermediary devices that bridge the analog temperature-dependent voltage signals and the digital processing circuits. The oscillators convert analog voltage signals into digital-compatible clock signals with temperature-dependent frequencies, enabling accurate temperature measurement while maintaining full digital circuit integration and scalability.
3Measurement precision
If a single oscillator is used, then circuit complexity is reduced, but temperature measurement accuracy and robustness are insufficient
Solution Approach 1:
The patent employs two oscillators with opposite temperature dependencies (one with positive temperature coefficient and one with negative temperature coefficient). These oscillators act as counterweights to each other, and their combined output through the digital circuit provides temperature measurement that compensates for individual oscillator variations, improving accuracy while maintaining manageable circuit complexity.
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 robust and accurate digital temperature measurement, facilitating scalable integration and precise thermal management within integrated circuits, while allowing for temperature calibration of oscillators.
Implementation Method 1
Both, voltage and time domain temperature sensors may exploit the temperature dependency of a bipolar pn-junction of silicon.
Implementation Method 2
Both, voltage and time domain temperature sensors may exploit the temperature dependency of a bipolar pn-junction of silicon.
Data Source
AI summary
A temperature sensor comprises a first oscillator to provide a first oscillation signal having a frequency that increases with increasing temperature and a second oscillator to provide a second oscillation signal having a frequency that decreases with increasing temperature. A time domain sigma-delta modulator is coupled to the first and the second oscillator to receive one of the first oscillation signal and the second oscillation signal to generate an output signal including a bitstream.