Rca Licensing Corporation

Peter D Osman

James H Wharton

A switching-type power supply for a video apparatus includes regulating circuits that respond to both voltage and current information in order to generate pulse width modulated signals for the power supply switching device. The regulating circuits are electrically nonisolated from the output load circuits to provide direct feedback from one of the load circuit voltage supplies in order to effect accurate regulation of the supply voltage. Primary current flow information is provided via an electrically isolated winding such that all regulation circuitry is electrically nonisolated from the load circuit supplies.

Regulator for isolated chassis power supply

A video apparatus capable of operating at different line deflection frequencies incorporates a CRT electron gun assembly heater supply voltage circuit that maintains a constant rms voltage level independent of the line deflection frequency. The heater supply includes a transformer winding located on the line deflection driver transformer. The duty cycle of the developed AC voltage waveform remains substantially constant independent of the line deflection frequency, so that the AC voltage may be applied to the heater circuit.

CRT filament supply for multiple frequency video apparatus

Size control circuitry allows the selection of a number of different combinations of raster heights and widths for a video display apparatus. A raster size selection signal is decoded to determine one of a number of possible height and width combinations. The height is determined by varying the vertical size feedback signal to the vertical deflection circuits. The raster width is determined by varying the operation of a side pincushion correcting diode modulator circuit.

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Indianapolis, IN, United States of America

Peter D Osman