Readout integrated circuit with multi-mode background suppression for long wavelength infrared focal plane arrays

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.