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Unidirectional/Bidirectional Drivers for Channel Interface

IP.com Disclosure Number: IPCOM000119913D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 51K

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This driver is used to interface the CPU and the channel control processor. (Image Omitted)

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Unidirectional/Bidirectional Drivers for Channel Interface

      This driver is used to interface the CPU and the channel
control processor.

                            (Image Omitted)

      The driver accepts a differential signal and generates a
voltage compatible with a ground down power supply system.

      The input to the driver is designed to have level shift
transistors T1, T2 as well as clamp circuitry R1, R2, T3 to avoid
input saturation.  In order to achieve the proper output voltage, an
open collector driver type was chosen. Transistors T4, T5 and
resistor R3 are used to shift down a voltage low enough to shut off
the output pull-down transistors (T out 1, 2, 3) while providing an
adequate base current when the output transistors are on.  T6 is a
short-circuit projection current mirror.

      RSLOW and TSLOW are both used to slow down driver transition
for noise reduction.  Redundant resistors are added where necessary
to improve yield.

      A bidirectional driver is a slight modification of the
unidirectional one.  The inhibit circuitry is added to electrically
set the driver to high impedance.  The inhibit circuit is a standard
ECL logic with level shift.

      Both drivers (unidirectional and bidirectional) are equipped
with chip-in-place enable circuitry for switching the driver off.
Thus, a chip can be isolated in a multi-chip package environment for
testing purposes.