	US 12,081,888 B2
	Reading circuit for a pixel array
Alexandre Mas, Montbonnot St Martin (FR); Abdessamed Mekki, Grenoble (FR); and Cedric Tubert, Saint-Egreve (FR)
Assigned to STMicroelectronics (Grenoble 2) SAS, Grenoble (FR)
Filed by STMicroelectronics (Grenoble 2) SAS, Grenoble (FR)
Filed on Apr. 21, 2022, as Appl. No. 17/660,084.
Claims priority of application No. 2105114 (FR), filed on May 17, 2021.
Prior Publication US 2022/0368847 A1, Nov. 17, 2022
Int. Cl. H04N 25/75 (2023.01); H03M 1/12 (2006.01); H03M 1/46 (2006.01); H04N 25/625 (2023.01); H04N 25/677 (2023.01)

CPC H04N 25/75 (2023.01) [H03M 1/1245 (2013.01); H03M 1/46 (2013.01); H04N 25/625 (2023.01); H04N 25/677 (2023.01)]

21 Claims

1. A read-out circuit comprising:

N inputs configured to be connected to N respective outputs of a pixel array of an image sensor, with N being an integer strictly greater than 1;

N analog-to-digital converters organized in K groups, with K being an integer strictly greater than 1 and strictly less than N, and each having a first input coupled to a respective one of the N inputs and a second input, each analog-to-digital converter being a correlated double sampling-type converter,

wherein, in each group, the second inputs of the analog-to-digital converters of the group are:

connected to each other,

electrically decoupled from the second inputs of the analog-to-digital converters of the other groups, and

configured to receive an identical first reference signal for all the analog-to-digital converters of the group;

a first circuit configured to provide a second reference signal; and

for each group, a first buffer circuit configured to receive the second reference signal and to provide the first reference signal of the group to the second inputs of the analog-to-digital converters of the group, wherein the second reference signal is a voltage ramp, and the first circuit comprises a digital-to-analog converter configured to provide the second reference signal.