Motorola Corporation

Zenith Radio Corporation

James J Parker

James P McShane

Gregory J Beaumont

Michael P Bafaro

Theodore J Godawski

A power supply for use in a computer terminal capable of providing a plurality of direct voltage signals to the computer terminal logic system while isolating this logic circuitry from the line voltage is disclosed. A high frequency power supply transformer and associated circuitry provides the various direct voltage signals to the computer terminal logic system and provides isolation between the line input and logic circuitry. Parallel isolation is provided by a horizontal sync coupling circuit which is driven by the logic system and which, in turn, synchronizes the horizontal deflection system. The direct voltage signals provided to the logic supply system are both scan- and pulse-derived from the horizontal sweep signal permitting various computer terminal systems to be operated by display-derived power output signals.

High frequency computer terminal power supply with isolation

Dynamic focus voltages for a CRT are obtained by utilizing the combined parabolic conversion wave shapes for control of the focusing electrode to provide sharp focus at all points in the raster. A current source is coupled to the focus divider chain and the conversion wave shape controls the current in the divider chain by controlling the resistance in a transistor. No high voltage capacitors are required since the dynamic voltages are coupled into the chain near the low voltage end.

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Elmhurst, IL, United States of America

James J Parker