Power supply unit for data viewing devices
US4079418A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 10, 1976 |
| Grant date | Mar 14, 1978 |
| Priority date | — |
| Expiry date | Jun 10, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M3/33553
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention relates to a power supply unit for data viewing devices, which, from a main alternating voltage produces at least one d.c. voltage for the operation of the data viewing device, where the power supply unit is in the form of a switching power supply unit and contains an oscillator which produces signals which determine the switching frequency of the switching power supply unit and where the data viewing device contains a pulse generator which, in order to produce an image on a screen, produces timing pulses of a given repetition frequency and a given duration. More particularly, the control stage for a switching power supply unit of a data viewing device having a display screen includes a free-running oscillator whose frequency is synchronized by timing pulses from a pulse generator. These pulses are of a predetermined repetition frequency and a given duration. The oscillator is preferably an astable multivibrator. The output signal of the oscillator is pulse modulated and fed to the base of a switching transistor in the power supply circuit. A separator stage such as an optical coupling element or transformer, is provided in the circuit between the pulse generator and …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.