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Flip-Flop Line Direction Switchers

IP.com Disclosure Number: IPCOM000039325D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01

Publishing Venue

IBM

Related People

Authors:
Edwards, DJ [+details]

Abstract

A redrive circuit for a two-way open-collector-driven signal line requires constant monitoring to determine the direction of redrive. If a microcontroller is used for this, it will have very limited time if any for other tasks. It may also be too slow in changing the direction of redrive. These disadvantages can be overcome by using a dedicated line-switcher circuit. The line-switcher circuit described here, consisting of a J-K flip-flop and two inverters, has fast direction detection and switch times and also has inputs to allow a microcontroller to over-ride the line-switcher and also to switch the redrive off altogether. (Image Omitted) The line switcher monitors both sides of the line-driver, and if they are different, it switches the direction of the driver.