Browse Prior Art Database

Small Signal NPN Impulse Driver

IP.com Disclosure Number: IPCOM000103225D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 35K

Publishing Venue

IBM

Related People

Banker, DC: AUTHOR [+4]

Abstract

A technique is described that enables the speed up of both rising and falling transitions of a small signal pulse used in driving a lossy transmission line. Complementary inputs at A and B are supplied by any suitable pre-driver.

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Small Signal NPN Impulse Driver

      A technique is described that enables the speed up of both
rising and falling transitions of a small signal pulse used in
driving a lossy transmission line.  Complementary inputs at A and B
are supplied by any suitable pre-driver.

      With input A at a quiescent up level, input B is at a down
level turning off T2 and allowing D2 to conduct and charge up its
depletion capacitance.  The voltage at the transmission line is held
at an up level by a suitable terminator at the end of the
transmission line.  When input signal at A is a down going
transition, the input at B goes positive, thus turning on T2 and also
discharging D2.  This requires increased current from the
transmission line resulting in a transient under shoot in the
negative transition.  At this time, D1 is conducting and charging up
its depletion capacitance.  When the input at A again has a rising
transition, D1 discharges and demands additional current from T1
resulting in a transition over shoot at the transmission line.

      The described technique results in improved performance in off
chip communicating circuits.

      Disclosed anonymously.