Correlation double sampling circuit for image sensor
US8125550B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 2008 |
| Grant date | Feb 28, 2012 |
| Priority date | — |
| Expiry date | Jul 28, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/76
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A correlation double sampling (CDS) circuit for sampling a reset signal and a light-sensing signal outputted from a pixel column of an image sensor includes two sampling capacitors and four transistor switches. The operation of the CDS circuit needs not change polarities of the two sampling capacitors, such that MOS capacitors that have higher capacitance per unit area can be utilized for realizing the two sampling capacitors for reducing thermal noises induced when performing sampling. Additionally, fewer transistors are used in the CDS circuit, and thus charge injection noises caused by switching the transistor switches can also be reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.