Cathode ray tube display with combined degauss and surge limiting circuit
US4769577A · kind A · utility
3Cited by
7References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 18, 1987 |
| Grant date | Sep 6, 1988 |
| Priority date | — |
| Expiry date | Mar 18, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/63
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A color cathode ray tube display includes a degauss coil and a switched mode power supply. The degauss coil is connected in series with the input rectifier (5) of the SMPS to limit the current surge on power on but is shorted out by a switch, preferably constituted by a triac, after the SMPS switching transistor turns on to give substantially zero residual degauss current. Forward voltage drop across the triac can be compensated for by back-to-back diodes (13) connected in series with the degauss coil. The triac is switched under control of a signal from an auxiliary winding on the SMPS output transformer (a).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.