Patent ID: 7907257

Claim:
A method of operating a time-of-flight imager pixel, said pixel having a light-sensitive region, a first and a second integration gate associated with said light-sensitive region, a first and a second sense node, a first output gate arranged between said first integration gate and said first sense node and a second output gate arranged between said second integration gate and said second sense node, said method comprising: a) exposing said light-sensitive region to light so as to optically generate charge carriers; b) collecting said charge carriers alternatively under said first and second integration gates; c) adjusting voltages on said first and second output gates and said first and second integration gates in such a way as to transfer a first portion of said charge carriers from said first integration gate into said first sense node and a second portion from said second integration gate onto said second sense node; d) calculating time-of-flight information based on said first and second portions of charge carriers; e) adjusting at least one voltage of the voltage on said first output gate and the voltage on said first integration gate so as to transfer, if said first integration gate is close to or in saturation, an amount of charge carriers form said first integration gate onto said first sense node; and f) testing whether a voltage change exceeding a given threshold was provoked on said first sense node by adjusting said at least one voltage in step e).