Analog-to-digital conversion in pixel arrays
US8446309B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 2, 2011 |
| Grant date | May 21, 2013 |
| Priority date | — |
| Expiry date | Jul 23, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/56
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An analog-to-digital converter (ADC) generates an output digital value equivalent to the difference between two analog signal values. The ADC 30 receives a first analog signal level, a second analog signal level and a ramp signal. A counter 32 is operable to count in a single direction. A control stage is arranged to enable the counter 32 based on a comparison 19 of the ramp signal with the first analog signal and the second analog signal. A digital value accumulated by the counter during a period when it is enabled forms the output. The ADC can perform the conversion during a single cycle of the ramp signal. The counter 32 can be loaded with a starting digital value representing an exposure level accumulated during a previous exposure period. Techniques are described for reducing the conversion time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.