A High-Sensitivity and Large-Dynamic Range Readout Circuit for Polysilicon-Based Microbolometer

In this paper, a high-sensitivity and large-dynamic range readout integrated circuit (ROIC) is designed for polysilicon microbolometer based on CMOS process. The ROIC employs a calibration-circuit which contains a correlated double sampling (CDS) circuit to suppress the pixel fixed pattern noise (FPN) and the offset voltage of the capacitive trans-impedance amplifier (CTIA) circuit. In addition, an automatic gain control (AGC) circuit is designed to further extend the dynamic range of the microbolometer. Results show that the ROIC can suppress 99.98% of the pixel FPN when the non-uniformity of the microbolometer is 0.2% and at least 99.45% of the offset voltage of the CTIA, while increasing the dynamic range by 20 dB due to the addition of the AGC.