Browse Prior Art Database

Printer Buffer Driver Control Circuit

IP.com Disclosure Number: IPCOM000090948D
Original Publication Date: 1969-Aug-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Duspiva, WS: AUTHOR [+2]

Abstract

This driver control circuit, for use with a Driver Gate circuit of a printer buffer, comprises similar Read and Write circuits. When the inputs to Read Input and 1 are Positive, transistor T1 turns on. The Read Gate Control point A goes negative, causing an associated Read Gate, which is addressed, to provide current through an array drive line of the buffer. When T1 conducts, transistor T2 turns off, allowing transistor T10 to conduct more heavily. This action turns on transistor T11 and pulls the Read Driver Control point C negative, thus turning on an associated driver, which is also addressed, and completing a current path through the array and controlling the magnitude of the current pulse.

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Printer Buffer Driver Control Circuit

This driver control circuit, for use with a Driver Gate circuit of a printer buffer, comprises similar Read and Write circuits. When the inputs to Read Input and 1 are Positive, transistor T1 turns on. The Read Gate Control point A goes negative, causing an associated Read Gate, which is addressed, to provide current through an array drive line of the buffer. When T1 conducts, transistor T2 turns off, allowing transistor T10 to conduct more heavily. This action turns on transistor T11 and pulls the Read Driver Control point C negative, thus turning on an associated driver, which is also addressed, and completing a current path through the array and controlling the magnitude of the current pulse.

The main current path is provided by a driver transistor in the Driver Gate circuit not shown. The current through the base of the driver transistor in the Driver Gate circuit is regulated at the Read Driver Control point C. This regulation involves two feedback loops. The major loop sets a voltage across resistor R26 equal to a reference voltage V. Such loop comprises a differential amplifier consisting of transistors T5, T6, and T7 which control the base current of transistor T10, thus setting the voltages on the base and emitter of transistor T11. Resistor R19 completes the negative feedback loop and sets a voltage across resistor R26, approximately equal to the reference voltage, with respect to the -3V supply. Networks of R16, C1...