A 4-Channel 20-to 300 Mpixel/s Analog Front-End with Sampled Thermal Noise Below kT/C for Digital SLR Cameras

摘要

We present a 4-channel analog front-end (AFE) designed specifically for multichannel sensors used in digital single-lens reflex (DSLR) cameras. Multichannel sensors have been adopted as a solution to the increasing requirements for higher throughput in imaging systems. Single-channel AFEs have been published [1-4]; however, there are drawbacks to using multiple discrete single-channel AFEs in a multichannel system. For example, column readout patterns are particularly sensitive to mismatch between AFE channels. Also, DSLR cameras support many different frame capture modes and readout patterns, requiring clock rates from below 10MS/s to over 70MS/s, and previous AFEs have not been designed to operate over such a wide range. This paper describes several design techniques developed for the DSLR application, including adaptive power scaling, an integrated reference buffer, and a low-noise sampling technique with sampled thermal noise below kT/C.