A 120 °C Operating Range TEC-Less Uncooled IRFPA With On-Chip Real-Time Ultralow Temperature Drift Compensation

This article presents a novel readout circuit architecture for uncooled infrared focal plane arrays (IRFPAs) that incorporates on-chip real-time compensation for ultralow dc voltage drift across a wide operating temperature range, without substrate temperature stabilization. A temperature drift model is developed to characterize the drift behavior caused by substrate temperature variations, forming the basis for a real-time compensation method. The proposed approach leverages a Wheatstone bridge-based readout architecture, incorporating a temperature-dependent nonuniformity correction (NUC) module to enable adaptive temperature drift correction. The proposed circuit is implemented using 180-nm CMOS technology, enabling the IRFPA to achieve a voltage drift of less than 2500 LSB over a wide temperature range of 120 °C. This corresponds to a ${77.3}\%$ reduction compared to traditional circuits. Furthermore, the IRFPA demonstrates robust shutter-less operation, achieving a peak signal-to-noise ratio (PSNR) of 26.93 dB during image stabilization. In addition, the design achieves a noise equivalent temperature difference (NETD) of less than 50 mK over the entire temperature range. This approach provides a new framework for on-chip temperature drift compensation, eliminating reliance on thermoelectric coolers (TECs) and mechanical shutters. It is particularly suited for compact, low-cost, low-power, and lightweight thermal imaging applications.