Temperature Sensor Circuit With Adjustable Voltage Source
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing temperature sensor circuits face challenges in achieving high measurement accuracy and protection from overloading, particularly due to sudden changes in resistance values when switching between different measurement ranges, and inadequate protection against short circuits.
Innovation Solution
A temperature sensor circuit utilizing a controllable voltage or current source connected to a measurement resistor, which allows for continuous adjustment of input voltage or current to maintain optimal operating conditions, incorporating a voltage divider resistor and current sensor to limit short-circuit current and reduce self-heating, while enabling precise differential voltage measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed resistor is used in the voltage divider to simplify the circuit, then the device complexity is reduced, but the measurement precision deteriorates due to inability to adjust for different temperature ranges
Solution Approach 1:
The patent applies dynamics by making the voltage divider resistor adjustable rather than fixed. The resistor value can be dynamically changed to match different temperature measurement ranges, allowing the circuit to maintain optimal precision across varying conditions while keeping the overall circuit structure relatively simple.
Solution Approach 2:
The patent changes the resistance parameter of the voltage divider resistor to optimize measurements for different temperature ranges. By adjusting this parameter, the circuit adapts to various measurement requirements, improving precision without requiring a completely different circuit design for each range.
2Adaptability or versatility
If the measurement range is widened by changing resistor values, then the adaptability is improved, but the device complexity increases due to need for multiple resistors and switching mechanisms
Solution Approach 1:
The patent makes a single voltage divider resistor serve multiple functions by making it adjustable. This single component can operate at different resistance values to cover various temperature measurement ranges, eliminating the need for multiple separate resistors and switching mechanisms, thus maintaining simplicity while achieving versatility.
3Measurement precision
If a controllable voltage source is added to continuously adjust input voltage, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent changes the voltage parameter by introducing a controllable voltage source that can adjust its output. This allows optimization of the measurement signal for different temperature ranges and conditions, improving precision. The complexity increase is managed by integrating this function into the existing circuit architecture.
4Reliability
If additional protective circuits are added to protect from overloading, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent implements protective circuits in advance to prevent overloading damage. These circuits are designed to activate before critical damage occurs, providing cushioning protection. The protection is integrated into the circuit design rather than added as separate external components, helping to manage complexity.
5Measurement precision
If the NTC thermistor is connected in a low-impedance manner to improve signal strength, then the measurement precision is improved, but the reliability deteriorates due to increased short-circuit risk
Solution Approach 1:
The patent changes the impedance parameter of the NTC thermistor connection from low to high. This reduces the short-circuit current and improves reliability by preventing overload damage. While this may reduce signal strength somewhat, the overall measurement system is optimized to maintain adequate precision while prioritizing protection.
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
This solution enhances measurement accuracy and protects the sensor from overloading by maintaining optimal operating conditions, reducing sudden changes and self-heating, and allowing for continuous adjustment of measurement ranges, thereby improving the reliability and precision of temperature measurements.
Implementation Method 1
The temperature of an electrical machine is currently usually measured with the aid of an NTC thermistor [NTC=negative temperature coefficient]
Implementation Method 2
the NTC thermistor usually forms, with a fixed resistor, a voltage divider. The divided voltage value across the NTC thermistor is converted into a digital signal
Implementation Method 3
the controllable voltage source can be used to deliberately vary the current flowing through the sensor in such a manner that the self-heating of the sensor is reduced
Data Source
AI summary
A temperature sensor circuit (1) for measuring a temperature, comprising a measuring resistor (2) and a controllable voltage source (3) or current source (3) which is connected to the measuring resistor (2) and by means of which an input voltage can be applied to the measuring resistor (2). The input voltage can be adjusted continuously by the controllable voltage source (3).