Pixel ramp generator for image sensor
US11303293B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 2021 |
| Grant date | Apr 12, 2022 |
| Priority date | — |
| Expiry date | Feb 28, 2041 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/78
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Techniques are described for implementing reduced-noise pixel ramp voltage generators for image sensors. The described pixel ramp voltage generators include circuit blocks to address various conventional causes of ramp generator noise. For example, a reference current is generated. Current steering can be used to toggle between a ramp-run mode for generation of a ramp voltage, and a ramp-stop mode for stopping the generation, thereby mitigating changes in low-frequency noise components between pixel conversion cycles, or phases or such cycles. Buffer multiplier techniques can be used to isolate kickback noise of the pixel conversion comparators from components generating the ramp voltage, such as to mitigate image smearing. Some implementations include additional features, such as sample-and-hold techniques used to isolate ramp generation components from current generation component noise, slope calibration techniques to dynamically tune voltage ramp slope, reset techniques, etc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.