A 0.18-μm CMOS SoC for a 100-m-Range 10-Frame/s 200 x 96-Pixel Time-of-Flight Depth Sensor

With the emerging need for high-resolution light detection and ranging (LIDAR) technologies in advanced driver assistance systems (ADAS), we introduce a system-on-a-chip (SoC) that performs time-correlated single-photon counting and complete digital signal processing for a time-of-flight (TOF) sensor. At the core of the 0.18-mu m CMOS SoC, we utilize linear arrays of 16 TOF and 32 intensity-only macro-pixels based on single-photon avalanche diodes in an original look-ahead concept, thus acquiring active TOF and passive intensity images simultaneously. The SoC also comprises an array of circuits capable of generating precise triggers upon spatiotemporal correlation events, an array of 64 12-b time-to-digital converters, and 768 kb of SRAM memory. The SoC provides the system-level electronics with a serial and low-bit-rate digital interface for: 1) multi-echo distance; 2) distance reliability; 3) intensity; and 4) passive-only intensity, thus mitigating system-level complexity and cost. A proof-of-concept prototype that achieves depth imaging up to 100 m with a resolution of 202 x 96 pixels at 10 frames/s has been implemented. Quantitative evaluation of the TOF sensor under strong solar background illuminance, i.e., 70 klux, revealed a repeatability error of 14.2 cm throughout the distance range of 100 m, thus leading to a relative precision of 0.14%. Under the same conditions, the relative nonlinearity error was 0.11%. In order to show the suitability of our approach for ADAS-related applications, experimental results in which the depth sensor was operated in typical traffic situations have also been reported.