Abstract: In the control system of ultra-low temperature freezers, achieving precise temperature control is a key technology. To address this issue, it is proposed to use platinum resistance PT100 sensors as temperature measurement tools, ensuring high precision and reliability of temperature measurement. A PT100 temperature measurement circuit based on 1 mA constant current source control is designed to achieve precise temperature control. Based on the calibration table of the PT100 sensor, the temperature measurement circuit was simulated and analyzed using Cadence simulation software. The results verified the accuracy of the circuit and solved the problem of precise temperature control in ultra-low temperature freezers. Meanwhile, through simulation analysis, circuit performance can be evaluated in advance and circuit design can be optimized, which greatly reduces development costs and time.

Key words: Ultra-low temperature freezer, PT100 sensor, Constant current source, Temperature measurement circuit, Simulation analysis