Image pickup apparatus with gain controlled output amplifier
US4466018A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 19, 1982 |
| Grant date | Aug 14, 1984 |
| Priority date | — |
| Expiry date | May 19, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/00
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Solid-state image pickup apparatus, such as an MOS imager, has a two-dimensional array of picture element units each formed of a photo sensitive element and a gating element. The picture unit elements discharge a signal charge onto vertical and horizontal transmitting lines in response to vertical and horizontal scanning pulses. Then, a resulting signal current is used to develop an output video signal. In order to give the output video signal a good S/N ratio, a gain-controlled current amplifier is employed. In several embodiments, the gain-controlled amplifier includes first through fourth transistors with the base-emitter junctions of the first and second transistors and of the third and fourth transistors connected in series, with a constant current source coupled to the first transistor, controlled current sources connected to the second and third transistors, and a load device coupled to the fourth transistor. In other embodiments, the gain controlled amplifier is formed of first, second, and third current mirror circuits connected in a balanced-current arrangement. Electrically variable resistances, e.g., MOS transistors, are coupled to the output transistors of the first an…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.