Light detecting circuit
US4626678A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 1984 |
| Grant date | Dec 2, 1986 |
| Priority date | — |
| Expiry date | Apr 4, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/6911
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A light detecting circuit in which noise superposed on a bias voltage of a photodiode is substantially canceled without the aid of a filter circuit employing an inductor. The photodiode is connected between a bias voltage terminal and an inverting terminal of a main amplifier, the latter being implemented with a differential amplifier or a comparator. A capacitance device is connected between the same bias voltage terminal and the other (noninverting) input terminal of the main amplifier. The capacitance device may be either a physical capacitor or a second photodiode which, in either case, should have a capacitance equal to the parasitic capacitance of the first photodiode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.