Universal Temperature Sensor Circuit for Thermistor and Diode Identification
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Solution Overview
Problem
Existing temperature sensors require specific design for different measurement devices, leading to inaccurate readings due to varying temperature characteristics, and there is a need for an apparatus that can automatically determine the type of temperature sensing load to obtain accurate measurements.
Innovation Solution
A temperature sensing apparatus comprising a current source circuit and a processing circuit that provides a test current to the temperature sensing load, determines its type based on the test voltage, and adjusts the current or reference voltage accordingly to generate a temperature sensing voltage, enabling accurate temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are designed according to specific temperature measurement devices with different characteristics, then measurement accuracy for that specific device is improved, but device complexity and design difficulty increase due to needing multiple specialized designs
Solution Approach 1:
The temperature sensing apparatus is designed to universally support multiple types of temperature sensing loads (thermistors with positive or negative temperature coefficients, diodes) through a single integrated circuit. The processing circuit automatically identifies the load type and adjusts measurement parameters accordingly, eliminating the need for multiple specialized sensor designs while maintaining high measurement accuracy for each device type.
Solution Approach 2:
The apparatus dynamically changes measurement parameters based on the identified temperature sensing load type. The processing circuit adjusts the test current magnitude and measurement methodology according to whether the load is a PTC thermistor, NTC thermistor, or diode, thereby optimizing measurement accuracy for each specific device characteristics without requiring separate hardware designs.
2Measurement precision
If temperature sensors use fixed measurement methods for specific device types, then measurement accuracy is improved, but adaptability to different temperature sensing loads deteriorates
Solution Approach 1:
The temperature sensing apparatus employs dynamic measurement methodology where the processing circuit first applies a test current to identify the temperature sensing load type by measuring the resulting test voltage, then dynamically switches to the appropriate measurement method and parameter settings based on the identification result. This dynamic adaptation enables high measurement accuracy across multiple device types including PTC thermistors, NTC thermistors, and diodes.
Solution Approach 2:
The apparatus implements a feedback-based identification process where the processing circuit measures the test voltage generated by the temperature sensing load in response to a test current, compares this measurement against expected characteristics, and uses this feedback to determine the load type. This feedback mechanism enables automatic adaptation to different device types while maintaining optimal measurement accuracy for each.
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 apparatus effectively interprets temperature sensing voltages from different loads, ensuring accurate temperature measurements by distinguishing between thermistors and diodes, and providing appropriate currents or reference voltages to achieve precise results.
Implementation Method 1
a semiconductor type temperature sensor measures an environmental temperature by use of a thermistor having a negative temperature coefficient
Implementation Method 2
a semiconductor type temperature sensor measures an environmental temperature by use of a thermistor having a negative temperature coefficient or a positive temperature coefficient
Implementation Method 3
temperature information is obtained by utilizing a characteristic of a diode device that a conduction voltage of the diode device changes with temperature
Data Source
AI summary
A temperature sensing apparatus and a temperature sensing method thereof are provided. A current source circuit provides a test current to a temperature sensing load, and the temperature sensing load generates a test voltage in response to the test current. A processing circuit determines a type of the temperature sensing load according to the test voltage, and determines a temperature according to the type of the temperature sensing load and a temperature sensing voltage generated by the temperature sensing load.