Miniature resistance temperature detector signal processing circuit with dual redundant design

Abstract

The Resistance Temperature Detector (RTD) signal processing circuit is an important part of the RTD temperature measurement module. In this paper, the RTD processing signal circuit with a dual redundant design is developed, which realizes the high-precision by the symmetrical design of the circuit layout and the precision control of components to ensure the consistency of the two outputs, and the error of the two output voltages is less than 0.36%. Meanwhile, the circuit adopts high-density thick film hybrid integration technology to realize circuit miniaturization. It is verified that the output voltages accuracy of the circuits for mass production is less than 0.19% at room temperature of 25°C, less than 0.39% at high temperature of 125°C, and less than 0.27% at low temperature of -55°C. The size of the circuit is only 14.40mm×14.40mm×3.55mm. This circuit can be widely used in the field of miniaturized and high-precision temperature measurement as a key device of high-reliability and general-purpose RTD temperature measurement module.