This invention relates to a pixel circuit comprising a photo-sensor stage (10) comprising a photodiode (1) delivering a photoreceptor current (Iph), a comparison stage (30) configured for detecting a change in a signal voltage (Vph) derived from said photoreceptor current, a sample-and-hold circuit (50) connected to the converting stage (20) and to the comparison stage (30), said comparison stage (30) configured to output an input signal for the sample-and-hold circuit (50), and for emitting a sampling signal to a control terminal of the sample-and-hold circuit (50) when a change is detected in the signal voltage (Vph).