The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 06, 2012
Filed:
Nov. 19, 2009
Matthew Purcell, Edinburgh, GB;
Graeme Storm, Forres, GB;
Derek Tolmie, Edinburgh, GB;
Mhamed El Hachimi, Edinburgh, GB;
Laurent Simony, Grenoble, FR;
Min Qu, Shanghai, CN;
Matthew Purcell, Edinburgh, GB;
Graeme Storm, Forres, GB;
Derek Tolmie, Edinburgh, GB;
Mhamed El Hachimi, Edinburgh, GB;
Laurent Simony, Grenoble, FR;
Min Qu, Shanghai, CN;
STMicroelectronics (R&D) Ltd., Marlow, Buckinghamshire, GB;
STMicroelectronics SA (Morocco), Bouskoura, MA;
STMicroelectronics (Grenoble 2) SAS, Grenoble, FR;
Abstract
An image sensor has a per-column ADC arrangement including first and second capacitors allowing a comparator circuit to perform correlated double sampling. The capacitors are continuously connected to, respectively, the analog pixel signal and a ramp signal without use of a hold operation. The comparator circuit comprises a differential input being connected to the junction of the two capacitors and being biased by a reference signal. The reference signal is preferably sampled and held from a reference voltage. The use of a differential input as first stage of the comparator addresses problems arising from ground voltage bounce when a large pixel array images a scene with low contrast. Connectivity of the differential input stage allows the ramp signal to see a constant capacitive load thus reduce image artifacts referred to as smear.