Circuit for reading a sensor having a pixel matrix with analog-to-digital conversion having a high acquisition rate, and image sensor including such a circuit

Abstract

A circuit for reading a pixel matrix array comprises, for each column of pixels of the matrix array: voltage-to-delay converting circuits receiving, on an input, a voltage value representative of the voltage of a read conductor of a respective column of pixels of the matrix array and delivering as output a binary signal called a comparative signal, this signal switched at a time dependent on the input voltage value; frequency-multiplying circuits, one for each of the voltage-to-delay converting circuits, receiving as input a primary clock signal and delivering as output secondary clock signals of multiplied frequency; and binary counters, receiving, on a first input, a the secondary clock signal, and, on a second input, a the binary comparative signal and counting at a rate dictated by the secondary clock signal until the binary comparative signal switches. An image sensor comprising a matrix array of pixels, in particular active pixels, and a read circuit is also provided.