Large-area imager with direct digital pixel output
US7139024B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 2002 |
| Grant date | Nov 21, 2006 |
| Priority date | — |
| Expiry date | Apr 2, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/78
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An imager circuit includes an array of pixels, each pixel including a sensor (photodiode) connected to an input terminal of a comparator. The comparators of each pixel row have output terminals connected to a latch. A counter generates a sequence of digital values that are transmitted to a digital-to-analog converter (DAC) and to the latch of each row. The DAC generates a ramp voltage that is transmitted to a second input terminal of each pixel's comparator. The comparators of a selected pixel column are enabled to generate output signals when the ramp voltage equals each pixel's voltage, causing the associated latches to capture the current digital values. The comparators are formed such that each pixel row shares a cascode mirror circuit that detects differential currents in data line pairs connected to each pixel in that row.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.