A 128×128 CMOS image sensor with analog memory for synchronous image capture

A 128×128 CMOS imager that permits synchronous capture is presented. The sensor combines the best of CMOS imagers (low-power, random readout, nondestructive readout, single supply voltage...) and synchronous capture [available in high-end charge coupled device (CCD) imagers]. The key point in obtaining such characteristics is the separation of the photosensor and the storage element. Although some sensors with these characteristics have been reported, in this sensor, the storage capability has been brought a step further, having storage times of the order of tens of seconds, and being able to use the array itself as a random access memory (RAM). This could avoid the use of external RAM, making the system simpler, more compact, and of low-power consumption