High dynamic range background light suppression for a TOF distance measurement sensor in 180nm CMOS

In this paper an integrated background light (BGL) immune single-pixel range finding sensor based on the time-of-flight (TOF) principle is presented. The sensor is fabricated in a standard 180 nm 1P6M CMOS process, reaching 40 × 40 μm² total pixel area, at a fill factor of ~ 67%. As a key element for the BGL suppression a current-sample-and-hold circuit is introduced. A resulting distance variation as a function of BGL remained in a 1.5 cm range for applied dc light of 180 klx, which is, to our best knowledge, the highest BGL immunity reported so far. Measurement results are carried out at 100 fps, showing a standard deviation of 8 mm at 1 m and ~ 4 cm for distances up to 3.2 m.