A light sensor (4) in which each of its pixels comprises: first and second MOS transistors (T1, T2) series-connected through their sources (S), a gate of the second transistor (T2) receiving a comparative voltage (Vcmp); a first current source (104) series-connected with said transistors (T1, T2) between a first supply voltage (GND) and a second supply voltage (VDD2); a third MOS transistor (T3) and a second current source (108) series-connected between a third supply voltage (GND) and a fourth supply voltage (VDD1), wherein the third transistor (T3) has a gate connected to a connection node (106) of the first current source (104) to the first and second transistors (T1, T2); a photodiode (PD) coupled to a gate of the first transistor (T1); and a switch (RST) connected to the gate of the first transistor (T1).