Column amplifier for high fixed pattern noise reduction
US6128039A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1999 |
| Grant date | Oct 3, 2000 |
| Priority date | — |
| Expiry date | Jan 11, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/78
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A column amplifier for high fixed pattern noise reduction. The column amplifier includes a switching capacitor amplifier, a sample and hold stage, and an output buffer. The switching capacitor amplifier receives signals from a bit line that is coupled to a column of active pixel sensors. The switching capacitor amplifier is capacitively coupled to the bit line from a column of active pixel sensors and is able to cancel the common mode offset in the bit line. The common mode can also be adjusted in the switching capacitor amplifier, such that the last stage of the column amplifier (e.g., the buffer stage) is not limited by the common mode level of the active pixel sensors. The switching capacitor amplifier includes an input capacitor and a feedback capacitor. The gain of the switching capacitor amplifier amplifies the pixel signals so that the fixed pattern noise introduced by stages after the switching capacitor amplifier will comprise a lower proportion of the total signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.