A Compact TOF Measurement Circuit with Photon Counting and Timing

This paper presents a compact photon flight time measurement circuit which collects photon information in two modes: the direct time-of-flight (D-TOF) and the indirect time-of-flight (I-TOF). In order to reduce the circuit dimension, only 16 MOSFETs and a small integral capacitor of 100fF are adopted. This circuit design is characterized by low static power dissipation of 20.4μW and good linearity. The differential non-linearity (DNL) of 0.45LSB in the D-TOF mode with the measurement range of 100ns is achieved. Moreover, the DNL of 0.4LSB in the 8-bit count range in the I-TOF mode is observed. The proposed TOF measurement circuit is good for high-density imaging array integration due to the small dimension and good performance.