Thermistor Temperature Sensor

Abstract

The invention provides a thermistor temperature sensor. A thermistor is adopted as a temperature sensing element and connected with a capacitor in series. Based on the transient process of a one-order resistance-capacitance circuit during charging or discharging, a timer is used for conducing timing once only on the charging process or the discharging process of the resistance-capacitance circuit, according to the timing result at the moment, a memory is searched for stored resistance-temperature characteristic data of the thermistor, the data is compared with the timing result, and then a measured temperature value is determined.

Description

technical field [0001] The invention provides a thermistor-type temperature sensor and relates to the technical field of using a thermistor to detect temperature. Background technique [0002] Thermistor is a commonly used temperature sensitive element. It is cheap and has high temperature sensitivity, such as negative temperature coefficient thermistor NTC, but its resistance temperature characteristic is nonlinear, which causes a lot of trouble for temperature measurement. The usual practice It is to connect the thermistor in series or in parallel with other linear resistors to reduce its non-linearity; or convert the terminal voltage of the thermistor to a corresponding digital signal through A / D, and then according to the digital signal, by searching in the memory Compare the temperature resistance characteristic data of the stored thermistor to determine the measured temperature value. The temperature measurement procedure of this method is simple. Since the A / D convert...

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Problems solved by technology

[0002] Thermistor is a commonly used temperature sensitive element. It is cheap and has high temperature sensitivity, such as negative temperature coefficient thermistor NTC, but its resistance temperature characteristic is nonlinear, which causes a lot of trouble for temperature measurement. The usual practice It is to connect the thermistor in series or in parallel with other linear resistors to reduce its non-linearity; or convert the terminal voltage of the thermistor to a corresponding digital signal through A / D, and then according to the digital signal, by searching in the memory Compare the temperature resistance characteristic data of the stored thermistor to determine the measured temperature value. The temperature measurement procedure of this method is simple. Since the A / D converter is used, the reference voltage used for temperature measurement is very high, that is, It is said that the accuracy of temperature measurement depends heavily on the reference voltage used; there is also a thermistor temperature measurement method based on the transient process of the first-order resistance-capacitance circuit, which respectively charges and discharges the resistance-capacitance circuit. The two timing results are calculated to obtain the code of the corresponding resistance value of the thermistor, and then the measured temperature value is determined by searching and comparing the resistance temperature characteristic data of the thermistor stored in the memory. This method has high temperature measurement accuracy and It has nothing to do with voltage, but the temperature measurement takes a long time, there are many temperature measurement programs, and the temperature measurement circuit is complicated

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