Horizontal banding reduction with ramp generator isolation in an image sensor
US9848140B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 2016 |
| Grant date | Dec 19, 2017 |
| Priority date | — |
| Expiry date | Apr 30, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/778
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A readout circuit for use in an image sensor includes a system ramp generator coupled to generate a system ramp signal. A plurality of analog-to-digital converters is coupled to a plurality of column bitlines from a pixel array to receive corresponding analog column image signals. An isolation ramp buffer is coupled between the system ramp generator and the analog-to-digital converters. The isolation ramp buffer includes a single input to receive the system ramp signal, and a plurality of isolated outputs. Each of the isolated outputs is coupled to provide an isolated column ramp signal to a corresponding analog-to-digital converter. Each of the of analog-to-digital converters is coupled to generate a corresponding digital column image signal in response to the corresponding analog column image signal and corresponding isolated column ramp signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.