PICTURE DISPLAY DEVICE COMPRISING A POWER SUPPLY CIRCUIT AND A LINE DEFLECTION CIRCUIT

摘要

A picture display device comprising a power supply circuit and a line deflection circuit. The power supply circuit comprises an inductance, and a switch switching at line frequency, the inductance forming part of a resonant network during the cut-off period of the switch. The line deflection circuit comprises a switch which also switches at line frequency and a line deflection coil which during the cut-off period, the retrace period, of this switch forms part of a resonant network which also comprises an inductance. A transformer winding is coupled to one of the inductances. Across this transformer winding there are pulses which are rectified for generating a supply voltage for a variable load. To reduce the internal impedance of the source formed, for example the high voltage source, the cut-off period of the supply circuit substantially coincides with the retrace period and the device comprises a connection for connecting at least during the conduction time of the rectifier a point of the transformer winding or of a winding coupled thereto to a point of the inductance not coupled to the transformer winding or of a further winding coupled to the said inductance, the said connection being substantially currentless in the non-loaded state of the source.