Dual-Oscillator CMOS Temperature Sensing With Frequency-Digital Readout
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Solution Overview
Problem
Conventional CMOS temperature sensors face issues of high power consumption, large circuit size, and difficulty in integration with other electronic circuits due to their analog characteristics, leading to inefficiencies and noise.
Innovation Solution
A CMOS temperature sensor design utilizing two oscillators, one with high sensitivity to temperature and another with low sensitivity, along with a multiplexer and frequency-to-digital converter, which selectively passes and converts frequency differences into digital codes, allowing for power-saving operation and high-resolution temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional analog temperature sensor circuits are used, then temperature detection capability is achieved, but power consumption is high and circuit size is large
Solution Approach 1:
The patent replaces conventional analog temperature sensor circuits with a digital oscillator-based temperature sensing system. The temperature detector uses oscillators whose oscillation periods vary with temperature, and an ADC converts these period differences into digital temperature readings. This substitution of analog circuits with digital oscillating circuits significantly reduces power consumption while maintaining temperature detection capability.
Solution Approach 2:
The patent changes the operating parameters of the temperature detection system by using oscillators with different oscillation periods that are both sensitive to temperature. By measuring the difference in oscillation periods between two oscillators and converting this difference to a digital value, the system achieves accurate temperature detection with lower power consumption compared to traditional analog circuits.
2Measurement precision
If conventional analog temperature sensor circuits are used, then temperature detection capability is achieved, but circuit size is large
Solution Approach 1:
The patent replaces complex analog temperature sensor circuits with a compact digital oscillator-based system. The temperature detector comprises oscillators, a multiplexer, and an ADC, which together occupy less chip area than conventional analog circuits while providing equivalent or superior temperature detection capability.
Solution Approach 2:
The oscillator-based temperature detection circuit can be integrated with other digital logic circuits and ADCs on the same chip, making it universally applicable in various digital systems. This multi-functionality allows the same circuit block to serve both as a temperature sensor and as part of the broader digital processing system, reducing overall circuit size.
3Duration of action of moving object
If oscillators are continuously operated for temperature detection, then continuous monitoring capability is achieved, but power consumption increases and noise occurs
Solution Approach 1:
The patent implements periodic temperature monitoring by controlling the oscillators to operate only during measurement intervals rather than continuously. The system can activate the oscillators and ADC when temperature measurement is required and deactivate them when not needed, achieving periodic monitoring with significantly reduced power consumption compared to continuous operation.
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 significantly reduces power consumption and sensor size while enhancing resolution, enabling efficient temperature detection with reduced noise and improved integration capabilities.
Implementation Method 1
a first oscillator that generates a first frequency signal
Implementation Method 2
a second oscillator that generates a second frequency signal
Implementation Method 3
a frequency-to-digital converter that converts a frequency difference between the first frequency signal and the second frequency signal into a digital code
Data Source
AI summary
A temperature sensor includes: a first oscillator that generates a first frequency signal; a second oscillator that generates a second frequency signal; a multiplexer that selectively passes the first frequency signal and the second frequency signal; and a frequency-to-digital converter that converts a frequency difference between the first frequency signal and the second frequency signal into a digital code.