A 40 m Range 90 frames/s CMOS Time of Flight Sensor Using SPAD and In Pixel Time Gated Pulse Counter
This letter presents a CMOS indirect time of flight (i ToF) image sensor, which is based on a single photon avalanche diode (SPAD) and a compact in pixel time gated pulse counter. The proposed SPAD based i ToF sensor makes it possible to achieve a time gated photon counting method at the pixel level and to enlarge a depth range up to 40 m while maintaining the pixel demodulation frequency up to 25 MHz. A prototype sensor is implemented in a 110 nm CMOS process and has a pixel array of <inline formula> <tex math notation="LaTeX"$64\times64$ /tex math>/inline formula> with a pixel pitch of <inline formula> <tex math notation="LaTeX"$32~\mu \text{m} /tex math>/inline formula> With a 3 D frame rate of 90 frames/s, the sensor achieves high 3 D image quality with a nonlinearity error below 2.25% and a relative precision error of 0.51% at a maximum distance of 40 m.
IEEE Solid State Circuits Letters