Dual-line distance sensor with on-chip phase generator and suppression of ambient light

A distance sensor is presented as a system-on-chip (SOC) solution embedding 2×32 pixels together with an on-chip ring oscillator providing phase-shifted modulation signals for the time-of-flight measurement principle. The low-power pixels consume only 2μA each, manage 150klx of ambient light directly in the circuit domain without using any optical filters, and show characteristic standard deviations of 1cm and 10cm at distances of 0.2m and 3.4m, respectively, while the linearity error is within ±5cm. The results are compared to the performance with externally-generated modulation signals and to a previous SOC design, which is outperformed by a factor of more than 25 in accuracy. Finally, measurement results of all 64 pixels are shown.