High resolution column-based analog-to-digital converter with wide input voltage range for dental X-ray CMOS image sensor
US7479916B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 3, 2007 |
| Grant date | Jan 20, 2009 |
| Priority date | — |
| Expiry date | Aug 3, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/56
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An imaging system including column-parallel ADCs that operate in response to a single slope global ramp signal and a matched global ramp line signal that has a voltage representative of a dark pixel value. The signal paths of the global ramp signal and the matched global ramp line signal are matched to minimize noise effects. Prior to performing a pixel read operation, the global ramp signal is increased through a first voltage range (below the dark pixel value) to ensure that the column-parallel ADCs are operating in a linear range. The first voltage range can be adjusted to cancel offset error associated with the column parallel ADCs. The column-parallel ADCs provide output signals having a full voltage swing between VDD and ground.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.