Random telegraph signal transients in active logarithmic continuous-time vision sensors

• Random Telegraph Signal (RTS) has been studied in an event-based vision sensor.
• High levels of RTS noise have been reported in sensors based on a logarithmic cell.
• RTS in closed-loop amplifiers may be amplified by the open-loop gain.
• RTS can explain hot-spots found in AER and SCD event-based vision sensors.

Random Telegraph Signal (RTS) is a well-known source of noise in current submicron circuits. Its static effects have been widely studied and its noise levels are in the order of other noise sources, especially for moderate submicron transistors. Nevertheless, RTS events may produce transients many times larger than the RTS itself, and this problem seems to have not yet been addressed. In this article we present results on the transients produced by RTS events in a smart vision sensor. RTS transients in closed-loop amplifiers can be many times greater than static RTS. The duration of the RTS transient may last for several milliseconds, and can be considered almost stationary for some conditions. The RTS transient effect has been modelled, and its impact on event-based vision sensors has been studied. This analysis may be also useful for many circuits based on closed-loop amplifiers. Some hints on how to reduce RTS transient effects on these sensors are also given, which may help with the design of current and future event-based vision sensors.