PN Junction Temperature Sensing With Reference Voltage Comparison
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Solution Overview
Problem
Conventional temperature sensors require high-performance IC testers and voltmeters to measure minute temperature changes, leading to increased manufacturing costs due to the need for high resolution and high voltage accuracy.
Innovation Solution
A temperature sensor device utilizing a PN junction element, variable current sources, and a constant voltage source to measure minute temperature changes without requiring high-performance IC testers, by digitally processing the output voltage and using a general IC tester.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional temperature sensor uses a diode to measure temperature from forward voltage difference, then temperature detection accuracy is improved, but manufacturing cost increases due to requiring high-performance IC testers and voltmers
Solution Approach 1:
The patent introduces a constant voltage source as an intermediary component that generates a reference voltage with the same temperature characteristics as the diode's forward voltage. This reference voltage serves as a mediator that allows the system to measure temperature using a general IC tester instead of requiring a high-performance IC tester, thereby reducing manufacturing costs while maintaining measurement accuracy
Solution Approach 2:
The patent changes the measurement parameter from directly measuring the diode's forward voltage (which requires high-performance equipment) to measuring the voltage difference between the diode's forward voltage and a constant reference voltage. This parameter transformation allows the use of general-purpose measurement equipment while maintaining temperature detection accuracy
2Measurement precision
If the amplification factor A is set to 100 or more to measure minute temperature changes of 0.1K, then temperature measurement resolution is improved, but the output voltage becomes 60V or more requiring high-voltage measurement capability
Solution Approach 1:
The constant voltage source acts as a mediator that enables the measurement of small voltage differences without requiring high amplification factors. By comparing the diode's forward voltage against this stable reference, the system can achieve high temperature resolution (0.1K) while keeping output voltages within manageable ranges that general voltmeters can handle
3Measurement precision
If a large resistor is used to store temperature data for digitization in conventional temperature sensors, then temperature measurement accuracy is improved, but product cost increases
Solution Approach 1:
The constant voltage source serves as an intermediary reference that enables accurate temperature measurement through voltage comparison rather than requiring large precision resistors for data storage and digitization. This approach maintains measurement accuracy while reducing the need for expensive large-value precision resistors in the circuit
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 device accurately measures minute temperature changes while reducing manufacturing costs by using a general IC tester and voltmeter, without the need for high-performance equipment.
Implementation Method 1
a temperature sensor which obtains a temperature from a difference in forward voltages when forward currents of at least two different current values are passed through a PN junction element
Data Source
AI summary
A temperature sensor device is capable of measuring minute temperature changes while being manufactured at low cost without needing a high performance IC tester. A temperature sensor device includes a temperature sensor circuit 2 and a temperature sensor 1. The temperature sensor 1 includes a PN junction element 15 which is a temperature sensing element, a variable current source which supplies different forward currents of at least two values to the PN junction element 15 and a constant voltage source 16 which outputs a constant voltage having the same temperature properties as a forward voltage of the PN junction element 15.