Readout integrated circuit with multi-mode background suppression for long wavelength infrared focal plane arrays
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Readout integrated circuit with multi‑mode background suppression for long wavelength infrared focal plane arrays Wukang Zhang1,2 · Honglei Chen1 · Ruijun Ding1 Received: 24 July 2020 / Accepted: 20 November 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Due to the large background current and the large dark current of non-uniformity, the readout integrated circuit (ROIC) will have the small dynamic range and the large spatial noise. For currently-used background and dark current suppression (BDS) techniques, reduction of spatial noise and provision of fast frame rates by a single circuit is impractical. In this paper, we propose a novel BDS circuit for use in different situations. With this circuit, three readout modes can be selected based on the magnitudes of the dark current and the background current, dynamic range, heterogeneity, and frame rate, while a double-threshold comparator is used to ensure the accuracy of BDS. To design the BDS module, we measured the dark current of a collection of long wavelength infrared mercury cadmium telluride photovoltaic detectors, to ensure that suppression could be provided for a statistically significant proportion of devices. Noise in the BDS module was analyzed based on BDS accuracy. Finally, the outputs obtained in the three readout modes were compared in simulation, to verify the operation of the BDS module. The BDS circuit can be used as reference for the large scale of an infrared focal plane array. Keywords Background suppression · ROIC · Long wavelength infrared MCT photovoltaic detector
1 Introduction The purpose of the MCT photovoltaic detector is to detect the target optical radiation. In order to improve the sensitivity of target detection, the carriers generated by the target radiation should be kept for a long time as much as possible, while reducing the proportion * Honglei Chen [email protected] * Ruijun Ding [email protected] Wukang Zhang [email protected] 1
Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
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University of Chinese Academy of Sciences, Beijing 100049, China
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of thermal excitation and background radiation excitation as much as possible (Hsieh et al. 1998; Kim and Lee 2002; Yazici et al. 2017). At high background environment, the background currents obtained by long wavelength infrared (LWIR) and very long wavelength infrared (VLWIR) detectors are comparable to the signal currents they produce and may occasionally be even greater than these signal currents (Woo et al. 2005a; Woo et al. 2005b). For these detectors, their dark current are also large (Yang et al. 1998). The dark current level is the key factor to determine the performance of the detector, which directly affects the target recognition distance and false alarm rate of the infrared system. The dark current of the HgCdTe infrared detector consists of diffus
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