A low-noise readout circuit in 0.35-μm CMOS for low-cost uncooled FPA infrared network camera

Simulation and Analysis of Uncooled Microbolometer for Serial Readout Architecture

“…Over the last decade, uncooled thermal imagers have gained significant importance due to their low-cost and highperformance solution. These thermal imagers are widely used in many applications including monitoring of thermal volcanic activity, medical equipment, condition monitoring, electrical inspection, heat-loss inspection of buildings, and military surveillance equipment [1][2][3]. As the technology advances, building a low-cost, low-power, compact thermal imager is a key challenge that involves research in many areas.…”

“…The primary function of the ROIC is to perform signal conversion and to send the data to the outputs. An ROIC should compensate for the noise sources and detectors self-heating during the biasing, background radiation, and significant variation in operating temperature [1]. The output of the ROIC is digitized by an analog-to-digital converter (ADC) and passed to the digital signal processing unit, which produces the final thermal image.…”

“…2 Journal of Sensors Microbolometer detector arrays are fabricated using the microelectromechanical systems (MEMS) technology [5,9]. Due to the variability within the material and process, each fabricated microbolometer has a different nominal resistance value corresponding to the same infrared radiation that introduces the FPN in detector arrays [1,2,10].…”

“…One-point NUC is based on the assumption that every detector has identical responsivity and that only the offset of each detector needs to be corrected, whereas the two-point correction algorithm corrects the offset and the responsivity [13]. In [1], individual calibration of current sources for biasing thermal detectors was proposed to reduce the nonuniformity. One of the common techniques is to use a blind microbolometer as a reference device along with a differential readout circuit [2].…”

“…The bias current should not be low enough such that it reduces the responsivity of the microbolometer [17]. A common compensation technique is to use a row of blind microbolometers that serves as a reference microbolometer [1,5,13,18]. A blind microbolometer is identical to a normal microbolometer but is not affected by incoming incident radiation; thus, it is only subjected to self-heating.…”