High voltage regulation by switching retrace capacitors

Abstract

A circuit for regulating an anode voltage in an information display apparatus. A horizontal deflection circuit has trace and retrace modes of operation. The horizontal deflection circuit further has a fixed retrace capacitance; and a series combination of a switched retrace capacitance and a switch element, which combination is coupled in parallel with the fixed retrace capacitance. The switch element is in a closed position as the horizontal deflection circuit enters the retrace mode of operation. A voltage divider network samples the anode voltage. A control circuit is responsive to the sample voltage for controlling the switch element, such that the control circuit effects regulation of the anode voltage by selecting a time during the retrace period at which to place the switch element in an open position. The control circuit may also provide a raster width compensation voltage for an east-west pincushion correction circuit.

Dependencies are inferred from the claim text.