HIGH VOLTAGE SUPPLY FOR A PICTURE TUBE

摘要

The high voltage supply for a picture tube (T) comprises a high voltage transformer (DST), which generates the anode voltage of the picture tube, and a high voltage module (M) with a switched mode power supply for providing a grid voltage, which is higher than the anode voltage. The output of the high voltage transformer (DST) is coupled to the transformer (TR) of the switched mode power supply, for adding the output voltage of the switched mode power supply to the high voltage of the high voltage transformer. Preferably, the transformer (TR) of the switched mode power supply provides the high voltage isolation, and at least the high voltage part of the module (M) including the transformer is potted with a resin. The high voltage module provides advantageously also an output (3) for a connection to the anode of the picture tube, so that the module can be used with present high voltage transformers, without requiring any modification. The primary side of the switched mode power supply comprises a control stage (9) with adjustable means for setting a specific output voltage of the power supply. In a preferred embodiment, this output voltage is adjustable between 300 and 500 Volts, with respect to the high voltage of the high voltage transformer.