Protection circuit for a cathode ray tube
US5089754A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 30, 1990 |
| Grant date | Feb 18, 1992 |
| Priority date | — |
| Expiry date | Apr 30, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N3/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A circuit for protecting a cathode ray tube screen from damage by an electron beam includes a semiconductor switch device having an input coupled to a signal related to a deflection signal for the electron beam. The switch device is coupled to a voltage supply and the circuit further includes a charge storage device coupled to the switch device and further coupled to a control grid of the cathode ray tube. The charge storage device is charged through the switch device by the voltage supply when the deflection signal is present at a control input of the switch device. The switch device decouples the supply voltage from the charge storage device when the deflection signal is not present and places a negative blanking voltage developed on the charge storage device across the control grid when the deflection signal is not present to cut-off beam current in the cathode ray tube.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.