Browse Prior Art Database

Active Pull Up Driver For Low End Interfaces

IP.com Disclosure Number: IPCOM000048614D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Culican, EF: AUTHOR

Abstract

This interface driver provides level conversion during the transition from one voltage level scheme to another.

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Active Pull Up Driver For Low End Interfaces

This interface driver provides level conversion during the transition from one voltage level scheme to another.

With the advent of VLSI, the need to lower the power dissipation per circuit and to increase the signal I/Os of the first level package have become more important. As more I/Os exist, the number of simultaneously switching drivers must also be increased. Both of these problems imply that the voltage supply should be decreased in magnitude and a new interface specification should be developed. During the transition period, communication between the existing technologies with VCC supply voltage and the new technology with a supply voltage of VC less than VCC must be maintained. Existing technologies use, for interface could be accomplished using an open collector drive with a resistor pull- up. This resistor cannot be included on chip because of power dissipation and it is undesirable to put it on the second level package because of density concerns.

The active driver shown in the figure can be used to solve these problems. The circuit basically provides active collector pull down (TB) and emitter follower pull-up (TA) functions. The AND-invert and AND-producing input logic sections are designed to eliminate the potential to have totem-pole current. The inputs produce opposite responses at nodes A and B, which control the "on" and "off" states of TA and TB, respectively.

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