Beam current limiting arrangement having a peak amplitude, responsive threshold
US5313294A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 14, 1992 |
| Grant date | May 17, 1994 |
| Priority date | — |
| Expiry date | Jan 14, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/645
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An automatic beam current limiting arrangement of a television receiver or display monitor comprises an average beam current limiter coupled to the low side of the high voltage transformer for reducing the contrast of a reproduced image when the average beam current exceeds a threshold and a peak current limiter coupled to the cathodes of the picture tube for controlling a current source which determines the threshold of the average beam current limiter in response to the sum of the cathode currents of the picture tube. In one embodiment, the cathode current sensing circuits comprise the same cathode current sensing circuits utilized in an automatic black level setting arrangement. This beam limiting arrangement allows operation at high contrast levels while inhibiting excessive peak white areas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.