Browse Prior Art Database

Six Bus Panel Driving System

IP.com Disclosure Number: IPCOM000087572D
Original Publication Date: 1977-Feb-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Lamoureux, WR: AUTHOR [+2]

Abstract

In certain types of gaseous discharge display devices, it is desirable to use phased select and deselect signals rather than the conventional amplitude select and deselect signals. Since the gaseous discharge display devices are driven by rectangular signals applied to selected horizontal and vertical axes, the intersection of such axes identifying the cell locations, varying the phase requires switching an output between two voltage levels, for example, +20 volts and ground.

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Six Bus Panel Driving System

In certain types of gaseous discharge display devices, it is desirable to use phased select and deselect signals rather than the conventional amplitude select and deselect signals. Since the gaseous discharge display devices are driven by rectangular signals applied to selected horizontal and vertical axes, the intersection of such axes identifying the cell locations, varying the phase requires switching an output between two voltage levels, for example, +20 volts and ground.

Such applications require driver transistors with a V(CEO) (collector/ emitter, open base) breakdown rating of 20 volts due to the switching action which temporarily eliminates current flow in the base circuit. Typically, transistors have much higher V(CBO) (collector base open) ratings than V(CEO) ratings, such that transistors having a V(CEO) rating of 20 volts may have a V(CBO) rating of 40 volts. Since a significant number of drivers are used in the gas panel and the choice and cost of the integrated-circuit technology varies with the component ratings, it is desirable to utilize a technology having as low a V(CBO) rating as possible.

One method of accomplishing this objective is illustrated in the circuit schematic of the figure, which illustrates the drive system for one axis of the gas panel display. To apply a Phi 1 signal to the output, the lower bus 12 is held at a reference voltage such as ground, transistor switch 1 is turned off and resistor 2 pulls up base 3 of transistor 4, thereby tu...