Cathode ray tube filament voltage control with a multifrequency deflection scanner
US6661188B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 24, 2003 |
| Grant date | Dec 9, 2003 |
| Priority date | — |
| Expiry date | Jan 24, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/63
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A power supply for a video display tube includes a deflection transformer with a primary winding powered with a scan voltage which has a first value when displaying signal according to a first video standard and a second voltage when displaying video according to a second standard. A secondary winding of the transformer produces filament voltage for the display tube. A variable coupler couples the filament voltage to the filament of the picture tube in an amount established by a control signal. A memory produces a first control signal in response to the first scan voltage and a second control signal in response to the second scan voltage. The first and second control signals are selected so that the voltage coupled from the transformer to the filament is the same at both scan voltages.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.