Light-detection system with programmable offset current
US5936866A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1997 |
| Grant date | Aug 10, 1999 |
| Priority date | — |
| Expiry date | Oct 23, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F39/18
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A photoelectric semiconductor light-detection system with programmable dynamic performance includes a semiconductor photocell, preferably a photodiode, by which the impinging light intensity can be converted into a proportional photoelectric current. The drain of a first MOS FET of corresponding channel-type operated to saturation is coupled to the semiconductor photocell, e.g., the cathode or anode of the photodiode, and its source is maintained at a constant potential. A second MOS FET applies a predetermined variable charge amount to the gate of the first MOS FET. A capacitor is provided at the gate of the first MOS FET. The difference between the offset current and the photoelectric current can be integrated by an integration device. A third MOS FET can be operated as a switch to read the integration device and to reset it at a given value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.