Column readout circuitry for amorphous silicon pixel amplifiers in digital imaging applications

Amorphous silicon (a-Si:H) technology provides an opportunity to develop large area X-ray imagers with enhanced benefits over existing imaging technology. An important application of a-Si:H X-ray imagers, and the motivation of this research, is the development of diagnostic digital X-ray imagers to aid in the diagnosis of patients by medical professionals. Moreover, a diagnostic X-ray imager is desired that can provide real-time digital fluoroscopic and high exposure chest radiographic imaging applications on the same X-ray medical equipment. This research presents an architecture for a lownoise custom designed medical imaging solution designed to extend the dynamic range of pixel amplification with a current-mediated a-Si:H active pixel sensor (APS), for diagnostic X-ray imaging. The proposed circuit design permits the ability to perform both real-time fluoroscopy, and higher contrast chest radiography. The medical imaging solution was implemented and simulated in CMOS 0.18 pm technology.