Сенсор різницевої температури на основі інтегруючого сигнального перетворювача
Date
2018-02-26
Journal Title
Journal ISSN
Volume Title
Publisher
Видавництво Львівської політехніки
Abstract
Здійснено розроблення сигнальних перетворювачів високочутливих сенсорів різницевої температури.
Первинними перетворювачами таких сенсорів є схемні каскади на біполярних транзисторах. З метою розширення
функціональних можливостей та підвищення роздільної здатності вимірювання різниці температур у сигнальному
перетворювачі використано схему інтегратора. Проведені експериментальні дослідження підтверджують високу
ефективність використання аналогового інтегратора в сенсорах різницевої температури, сигнальні перетворювачі яких
поєднують високу точність та часову роздільну здатність вимірювання.
The work is devoted to the problem of signal transducers of high-sensitivity differential temperature sensors. The conducted studies have shown that the scheme of the signal converter with the stabilization of the total emitter currents of a transistors pair is characterized by a combination of high sensitivity and stability of the steepness of a transformation function. In particular, as compared to the circuit with the stabilization of the collector current of a reference transistor, the instability of steepness is reduced 20-fold. The research of the developed signal converters and their parametric analysis was carried out on the basis of transistors SPICE models. For the number of modern sensors problems, in particular in micro and nanocalorimetry, a combination of high resolution of measurement of differential temperature and the speed of such measurement is necessary. Obviously, these requirements are inherent in the contradiction, i.e. increasing the speed leads to an inevitable loss of measurement accuracy. To eliminate this contradiction, the scheme of the signal converter on the basis of an integrator, which allows increase the resolution of the temperature difference measurement, is proposed. In the schemes of the signal converter of differential temperature and the integrator, the high-precision operational amplifier of series AD8551 / AD8552 / AD8554 have been used. They operate on principle of the signal modulationdemodulation, which allows reach the minimum values of the bias voltage and its instability of 0.005 mV/°C. The characteristic relationship between accuracy and measurement time on the basis of the high-precision micro converter ADuC834 based on 24-bit sigma-delta (S-D) ADC used in the developed sensor of differential temperature is considered. Experimental results of the developed sensor investigation have underlined the significant exactness: depending on the ADC range, the non-reproducibility of the voltage measurement is within ± 1 (10) μV, which corresponds to the resolution of the temperature measurement ±(10–4…10–3)°C.
The work is devoted to the problem of signal transducers of high-sensitivity differential temperature sensors. The conducted studies have shown that the scheme of the signal converter with the stabilization of the total emitter currents of a transistors pair is characterized by a combination of high sensitivity and stability of the steepness of a transformation function. In particular, as compared to the circuit with the stabilization of the collector current of a reference transistor, the instability of steepness is reduced 20-fold. The research of the developed signal converters and their parametric analysis was carried out on the basis of transistors SPICE models. For the number of modern sensors problems, in particular in micro and nanocalorimetry, a combination of high resolution of measurement of differential temperature and the speed of such measurement is necessary. Obviously, these requirements are inherent in the contradiction, i.e. increasing the speed leads to an inevitable loss of measurement accuracy. To eliminate this contradiction, the scheme of the signal converter on the basis of an integrator, which allows increase the resolution of the temperature difference measurement, is proposed. In the schemes of the signal converter of differential temperature and the integrator, the high-precision operational amplifier of series AD8551 / AD8552 / AD8554 have been used. They operate on principle of the signal modulationdemodulation, which allows reach the minimum values of the bias voltage and its instability of 0.005 mV/°C. The characteristic relationship between accuracy and measurement time on the basis of the high-precision micro converter ADuC834 based on 24-bit sigma-delta (S-D) ADC used in the developed sensor of differential temperature is considered. Experimental results of the developed sensor investigation have underlined the significant exactness: depending on the ADC range, the non-reproducibility of the voltage measurement is within ± 1 (10) μV, which corresponds to the resolution of the temperature measurement ±(10–4…10–3)°C.
Description
Keywords
сенсор температури, інтегратор, транзисторні структури, конвертер, Temperature Sensor, Integrator, Transistor Structure, Converter
Citation
Бойко О. В. Сенсор різницевої температури на основі інтегруючого сигнального перетворювача / О. В. Бойко, Р. Л. Голяка, З. Ю. Готра // Вимірювальна техніка та метрологія : міжвідомчий науково-технічний збірник. — Львів : Видавництво Львівської політехніки, 2018. — Том 79. — № 3. — С. 25–36.