Temperature Sensor Using Voltage Divider for Precision Measurement
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Solution Overview
Problem
Conventional temperature sensors face challenges in accurately measuring minute temperature changes due to errors caused by variations in diode saturation current, requiring high-performance voltmeters and complex measurement circuits, which increase costs and complexity.
Innovation Solution
A temperature sensor design incorporating a PN junction element, a variable current source supplying different forward currents, a constant voltage source with the same temperature properties as the PN junction element, and an amplifier to amplify the difference between the forward voltage and the constant voltage, allowing for accurate measurement of minute temperature changes with reduced complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional temperature sensor uses a diode with amplification factor A of 100 or more to measure minute temperature changes, then the measurement precision is improved, but the output voltage becomes 60V or more which requires high-performance voltmeters and increases device complexity
Solution Approach 1:
The patent extracts the temperature sensing function from the forward voltage measurement and implements it through a voltage divider circuit. The voltage divider converts the diode's forward voltage into a proportional output voltage that can be measured directly without high amplification, thereby simplifying the measurement circuit while maintaining temperature measurement capability
Solution Approach 2:
The patent creates a simplified copy of the temperature sensing mechanism by using a voltage divider circuit that replicates the temperature dependence of the diode's forward voltage. This copy produces an output voltage that directly reflects temperature changes without requiring complex amplification circuits
2Measurement precision
If a conventional temperature sensor uses high amplification factor to measure minute temperature changes, then the measurement precision is improved, but the cost increases due to requirement of high-performance voltmeters
Solution Approach 1:
The patent replaces expensive high-performance voltmeters with a simple voltage divider circuit using inexpensive resistors. This substitution achieves the same measurement function at a fraction of the cost, making the temperature sensor economically viable for mass production and widespread application
3Measurement precision
If a conventional temperature sensor removes factors causing errors from diode saturation current variations, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent merges the temperature sensing function with a simple voltage divider circuit, combining the diode's temperature-dependent forward voltage characteristic with resistive voltage division. This integration achieves error compensation for diode saturation current variations without adding complex circuitry, maintaining simplicity while improving accuracy
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
Enables accurate measurement of minute temperature changes with a low-cost, easy-to-use setup, eliminating the need for high-performance voltmeters and simplifying the measurement circuit, while maintaining accurate temperature coefficient measurements.
Implementation Method 1
a PN junction element which is a temperature sensing element
Implementation Method 2
an amplifier which amplifies a difference between the forward voltage of the PN junction element and the constant voltage
Data Source
AI summary
A low-cost and easy-to-use temperature sensor is capable of measuring minute temperature changes. A temperature sensor 1 includes a diode 15 which is a temperature sensing element (PN junction element), a variable current source 10 which supplies at least two different forward currents I1 and I2 to the diode 15, a constant voltage source 16 which outputs a constant voltage Vb having the same temperature properties as a forward voltage Vf of the diode 15 and an amplifier 17 which amplifies a difference between the forward voltage Vf of the diode 15 and the constant voltage Vb.