Digital Temperature Sensor Circuit Without High-Gain Amplifiers
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Solution Overview
Problem
Conventional temperature sensors for integrated circuits face challenges in providing accurate digital signals with high resolution and low power consumption while occupying minimal surface area, due to the need for high amplification and accurate analog-to-digital conversion within limited voltage ranges.
Innovation Solution
A temperature sensor design featuring a current-switching digital-to-analog converter with a ladder network and a unique biasing system, where the output terminals are maintained at a constant voltage distinct from the sensor ground, allowing for efficient conversion and reduced component count, thereby minimizing errors and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an amplifier with high and accurate amplification factor is used to amplify the temperature signal, then the signal accuracy is improved, but the device complexity and surface area increase
Solution Approach 1:
The patent extracts and eliminates the amplifier component from the temperature sensor circuit. Instead of using a separate amplifier to boost the temperature signal, the design directly feeds the analog temperature signal into the analog-to-digital converter, simplifying the overall device structure while maintaining measurement accuracy through direct conversion.
Solution Approach 2:
The patent introduces a reference signal as an intermediary element that is subtracted from the amplified temperature signal before digital conversion. This reference signal serves as a mediator to compensate for offset errors and improve measurement accuracy without requiring a high-gain amplifier, thus reducing device complexity.
2Measurement precision
If an amplifier with high and accurate amplification factor is used to amplify the temperature signal, then the signal accuracy is improved, but the power consumption increases
Solution Approach 1:
The amplifier is extracted and removed from the circuit, eliminating its power consumption. The design achieves signal conditioning through direct connection to the ADC and uses a reference signal for offset compensation, thereby reducing overall power consumption while maintaining signal accuracy.
3Measurement precision
If the analog-to-digital converter is designed to translate small voltage variations with high resolution, then the measurement precision is improved, but the device complexity and power consumption increase
Solution Approach 1:
The patent applies preliminary action by pre-subtracting a reference signal from the temperature signal before digital conversion. This preprocessing step compensates for offset errors in advance, allowing the ADC to operate with standard resolution requirements while maintaining high measurement precision, thus reducing device complexity.
4Measurement precision
If the analog-to-digital converter is designed to translate small voltage variations with high resolution, then the measurement precision is improved, but the power consumption increases
Solution Approach 1:
The reference signal subtraction is performed as a preliminary action before the ADC conversion process. This pre-processing step reduces the burden on the ADC by compensating for offset errors in advance, allowing the use of lower-power ADC designs while maintaining high measurement precision.
Data Source
AI summary
An embodiment of a temperature sensor providing a digital signal representative of temperature comprises a measurement unit providing a first measurement current equal to the sum of at least a first current proportional to temperature and of a second current; a comparator capable of providing a comparison signal which depends on the comparison between the first current and the difference between a third current and the second current; a coding unit receiving the comparison signal and providing said digital signal; a digital-to-analog converter capable of providing the second current and the third current, said difference corresponding to the conversion of said digital signal; and a unit for providing a reference voltage.