Temperature Sensing Circuit Using a Constant Reference Signal
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Solution Overview
Problem
Temperature sensing devices suffer from reduced sensing linearity due to the use of two variable sensing signals, which are subjected to division or subtraction operations, leading to significant errors in voltage variation.
Innovation Solution
A temperature sensing device and method that employs a sensor generating two distinct sensing signals based on different conditions, with a conversion circuit performing subtraction, multiplication, and division operations to generate an output digital code value, where one signal is a constant, thereby maintaining high sensing linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two variable sensing signals are used for temperature sensing, then the device can compensate for voltage variation through division or subtraction operations, but the sensing linearity is significantly reduced
Solution Approach 1:
The patent changes the parameter of the sensing signals by using one constant signal and one variable sensing signal instead of two variable signals. This parameter change allows the division operation to maintain sensing linearity while the constant signal provides a stable reference for voltage variation compensation.
Solution Approach 2:
The patent uses a constant sensing signal as a reference copy that mirrors the voltage variation characteristics without containing temperature information. This constant copy allows the system to compensate for voltage variations by comparing the variable sensing signal against the stable reference, thereby maintaining both reliability and measurement precision.
2Reliability
If division operation is performed on two sensing signals to reduce voltage variation error, then voltage compensation is achieved, but the linearity of temperature sensing is degraded
Solution Approach 1:
The patent changes the parameter of one sensing signal from variable to constant, which fundamentally alters the division operation's behavior. By dividing a variable sensing signal by a constant reference signal, the system achieves voltage compensation while preserving the linear relationship between the sensing signal and temperature, thus resolving the linearity degradation issue.
3Reliability
If subtraction operation is performed on two variable sensing signals, then voltage variation can be compensated, but the sensing accuracy is significantly reduced
Solution Approach 1:
The patent introduces a constant sensing signal as a stable reference copy that captures voltage variation characteristics. By subtracting this constant reference from the variable sensing signal, the system compensates for voltage variations while maintaining sensing accuracy, as the constant signal provides a reliable baseline without introducing the errors associated with using two variable signals.
Data Source
AI summary
A temperature sensing device and a temperature sensing method are provided. The temperature sensing device includes a sensor and a conversion circuit. The sensor generates a first sensing signal and a second sensing signal corresponding to a temperature based on different conditions. The conversion circuit performs a subtraction operation on the first sensing signal and the second sensing signal to obtain a result difference value, calculates a compensation value according to the result difference value and the first sensing signal, multiplies the result difference value and the compensation value to obtain a multiplication value, subtracts the multiplication value from the first sensing signal to generate a first value, adds the multiplication value to the first sensing signal to generate a second value, and divides the first value by the second value to generate an output value. The second value is a constant.