Temperature Detection Circuit with Transistor Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional temperature detection devices experience reduced accuracy due to aging deterioration and temperature variations in the transistor's on-state, affecting the accuracy of temperature detection and making it difficult to detect sensor failures.
Innovation Solution
A temperature detection device comprising plural resistors and a transistor, where the transistor's on-state and off-state are switched to alter the temperature-voltage characteristic of the sensor voltage, allowing for improved accuracy by detecting both sensor voltage and transistor output voltage, and enabling detection of sensor failures across various temperature ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the transistor is in the on-state to improve temperature detection range, then the temperature-voltage characteristic varies with aging deterioration and temperature, but temperature detection accuracy deteriorates
Solution Approach 1:
The detection section detects the transistor output voltage and feeds back this information to correct the temperature calculation. By using the detected transistor output voltage as a reference, the system compensates for aging deterioration and temperature variations, maintaining accurate temperature detection even when the transistor is in the on-state
Solution Approach 2:
The system changes the operational parameters by detecting both sensor voltage and transistor output voltage, then calculating temperature based on both parameters. This dual-parameter approach allows the system to adapt to varying transistor characteristics while maintaining detection accuracy across different temperature ranges
2Device complexity
If a single pull-up resistor configuration is used to simplify the circuit, then device complexity is reduced, but temperature detection accuracy deteriorates due to inability to detect sensor failures
Solution Approach 1:
The transistor serves multiple functions: it acts as a switch to change the pull-up resistor configuration, provides an additional voltage detection point, and enables failure detection capability. This multi-functionality allows the circuit to maintain simplicity while achieving improved detection accuracy and reliability
3Reliability
If the transistor is switched on and off to vary pull-up resistor value to improve failure detection, then reliability is improved, but temperature detection accuracy deteriorates due to voltage variation with aging
Solution Approach 1:
The system continuously monitors the transistor output voltage and uses this feedback to correct temperature calculations. This feedback mechanism compensates for voltage variations caused by aging deterioration, maintaining accurate temperature detection while preserving the reliability benefits of transistor switching
Solution Approach 2:
The temperature detection system combines multiple voltage detection points (sensor voltage and transistor output voltage) to create a composite measurement approach. This composite methodology integrates information from both voltage points to achieve both failure detection and accurate temperature measurement simultaneously
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 solution enhances temperature detection accuracy by switching between different temperature-voltage characteristics, allowing for precise temperature calculation and failure detection, even when the transistor is in the on-state, thereby improving the overall reliability of temperature measurements.
Implementation Method 1
a temperature sensor, which varies its resistance value in accordance with temperature
Implementation Method 2
the transistor is switched over to turn on and off to vary the resistance value of the pull-up resistor
Implementation Method 3
The temperature detection device detects the sensor voltage and calculates the temperature of the detection object based on a detection value of the sensor voltage
Data Source
AI summary
A temperature detection device is connected to a temperature sensor, and includes two resistors, a transistor and a microcomputer. The temperature sensor is connected to ground. The resistors are connected in series between the temperature sensor and a power supply line. The transistor is connected to the resistor, which is at the power supply line side. The microcomputer switches over a characteristic of a sensor voltage, which is developed at a junction between the resistor and the temperature sensor, to a first characteristic and a second characteristic by switching over the transistor to an on-state and an off-state. The microcomputer calculates a temperature based on the sensor voltage. When the transistor is in the on-state, the microcomputer detects a voltage developed at a low-potential side output terminal of the transistor and calculates the temperature based on the transistor output voltage and the sensor voltage.