Regulated switching power supply device, especially for a visualisation apparatus, and apparatus comprising such a device

Abstract

Abstract 1. Controlled switching power supply whose outputs furnishing supply direct voltages are galvanically separated from the mains which feeds them by way of a first rectifier circuit (1-7) by means of an isolation and supply transformer (12) whose primary winding (11) is connected in series with the collector-emitter path of a switching transistor (13) between the output terminals (6, 8) of the latter, the base of the switching transistor (13) being coupled to the output of a control and pilot circuit (20) which supplies thereto rectangular signals with cyclic ratio variable as a function of a control information supplied by one of the isolated outputs (43, 38) and transmitted via an optocoupler (61) to the control input of the control and pilot circuit (20), to the synchronization input of which is likewise applied in galvanically isolated manner a synchronization information originating from a periodically functioning circuit such as a horizontal deflection circuit fed by one of the isolated outputs of the device, characterized in that the synchronization information is superimposed without dc component on the control information in front of the optocoupler (61) and in that it is separated therebehind from the latter by means of a high-pass filter (69, 70) and a low-pass filter (65, 66, 251, 73, 74) which respectively feed the synchronization input and the control input of the control and pilot circuit (20).

Inventors

• 👤 Patrice Soulard

Bibliographic Details