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http://dx.doi.org/10.46670/JSST.2022.31.2.115

Realization of Readout Circuit Through Integrator to Average MCT Photodetector Signals of Noncontact Chemical Agent Detector  

Park, Jae-Hyoun (Nano Convergence Technology Research Center, Korea Electronics Technology Institute)
Publication Information
Journal of Sensor Science and Technology / v.31, no.2, 2022 , pp. 115-119 More about this Journal
Abstract
A readout circuit for a mercury-cadmium-telluride (MCT)-amplified mid-wave infrared (IR) photodetector was realized and applied to noncontact chemical agent detectors based on a quantum cascade laser (QCL). The QCL emitted 250 times for each wavelength in 0.2-㎛ steps from 8 to 12 ㎛ with a frequency of 100 kHz and duty ratio of 10%. Because of the nonconstant QCL emission power during on-duty, averaging the photodetector signals is essential. Averaging can be performed in digital back-end processing through a high-speed analog-to-digital converter (ADC) or in analog front-end processing through an integrator circuit. In addition, it should be considered that the 250 IR data points should be completely transferred to a PC during each wavelength tuning period of the QCL. To average and minimize the IR data, we designed a readout circuit using the analog front-end processing method. The proposed readout circuit consisted of a switched-capacitor integrator, voltage level shifter, relatively low-speed analog-to-digital converter, and micro-control unit. We confirmed that the MCT photodetector signal according to the QCL source can be accurately read and transferred to the PC without omissions.
Keywords
readout circuit; chemical agent detector; switched-capacitor integrator; MCT photodetector; QCL;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
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