Apparatus and method for determining whether a photodiode saturates and outputting a digital value representing a charge from that photodiode based on that determination
US10812742B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 11, 2019 |
| Grant date | Oct 20, 2020 |
| Priority date | — |
| Expiry date | Apr 11, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B2027/0118
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In one example, an apparatus comprises: a photodiode, a charge storage unit, and an analog-to-digital converter (ADC) circuit. In a first mode, the ADC circuit can compare a first voltage representing a quantity of the overflow charge stored at the charge storage unit against a first ramping voltage to generate a first decision; and obtain, based on the first decision output, a first digital value. In a second mode, the ADC circuit can compare a second voltage representing a quantity of residual charge stored in the photodiode against a second ramping voltage to generate a second decision, and obtain, based on the second decision, a second digital value. The ADC circuit can determine, based on one of the first decision output or the second decision output, whether the photodiode saturates, and output one of the first digital value or the second digital value to represent an intensity of incident light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.