CMOS Design for a Smart Focal Plane Array

A smart focal plane array has been designed that incorporates the functions of edge extraction, brightness adaptation, and moving-object detection. The design is based on a concept first presented by Mead and Mahowald, who built a silicon retina that was modeled on the distal portion of the vertebrate retina. Their chip generated, in real time, outputs that correspond directly to signals observed in the corresponding levels of biological retinas the design employed a resistive network to perform signal aggregation between cells. The design presented in this report is compatible with complementary metal oxide semiconductor CMOS technology and can be readily fabricated through MOSIS MOS implementation system. The layout of a prototype array was created with the MOSIS scalable CMOS n-well analog 2.0-micron process. Although the array presented here uses Si phototransistors, the architecture is applicable to any semiconductor system in which pnp transistors and MOSFETs MOS field-effect transistors can be produced. Therefore it could be adapted for use with GaAs quantum-well infrared photodetectors QWlPs to produce smart focal plane arrays in the infrared. In addition, the design is appropriate for HgCdTe detectors if selected area growth on Si is possible. A preliminary design in which each pixel is connected to a light-emitting diode LED is also discussed.