POWER SUPPLY PROTECTION CIRCUIT

摘要

A horizontal deflection circuit includes a flyback transformer. A secondary winding of the flyback transformer is coupled in series with a diode switch to produce a trace rectified supply voltage that energizes a vertical deflection amplifier. The diode switch also provides switching operation in an East-West diode modulator. During, for example, service mode operation, when the vertical raster is collapsed, the current in the secondary winding during trace is substantially reduced. The reduced current during trace is sensed for producing a control signal that causes the peak current supplied to the diode switch by the diode modulator to be smaller than the current in the secondary winding. This ensures that the diode switch remains conductive throughout horizontal trace, thereby preventing an undesirable increase in the supply voltage from occuring.