Design of infrared signal detection circuit in a temperature calibration system

In order to improve the accuracy of infrared detectors to detect the infrared weak signal, a preamplifier circuit was built with a constant current bias circuit and a low-noise high-speed operational amplifier. The equivalent noisy model was deduced based on the circuit theory. The output voltage noise of the 1st amplification circuit was calculated with the superposition method. In temperature blackbody furnace experiment, the circuit performance was tested, the voltage waveform at 500℃~700℃ was obtained, and signal-to-noise ratio of 7.25×103 was obtained. The results show that the preamplifier circuit of infrared detection achieves the application goal of high signal-to-noise ratio, response speed and strong anti-jamming performance, it can be used to amplify the weak infrared signal.