Pulse-width-modulated converter for television system

摘要

This invention is applicable to a television system, for example a television camera system, which includes a source of timing signals that are synchronized in time with blanking intervals which occur between active portions of the video signals generated by said television system. The invention is directed to an improved pulse-width-modulated converter which converts a source of direct voltage to a regulated supply of direct voltage having a minimum of perturbations occurring during active portions of the video. In accordance with the invention there is provided a transformer having primary and secondary windings. Means responsive to the timing signals are provided for generating an alternating voltage. Switching means coupled to the primary winding are responsive to the alternating voltage for alternately applying the unregulated source of direct voltage in opposite relative polarities across the primary winding. A rectifier is coupled to the secondary winding and filter means receive the output of the rectifier. Further provided is a pulse generating means responsive to the voltage output level of the filter and the timing signals for generating a series of pulses which are in synchronism with the timing signals and which have widths that vary as a function of the voltage output level. Finally, inhibit means are provided which are responsive to the pulses for inhibiting the application of the unregulated voltage across the primary winding during the pulses.