Zenith Data Systems Corporation

Saifee Fakruddin

Mark J Foster

Robert A Kohtz

Clark L Buxton

Jeff Schindler

A computer bus interface suited to connecting an expansion bus to a computer's internal bus. The interface is capable of selecting and deselecting any devices coupled to the expansion bus by enabling and disabling buffers which intercept signals between the expansion bus and the internal bus.

External expansion bus interface

A method and apparatus for monitoring the voltage discharge of a battery power supply while under load, and to manage the power supply by accurately calculating the time the useful charge is nearly depleted, providing a series of warnings to the user-operator of that fact, and subsequently performing a system shutdown before a complete discharge of the battery. If the invention is applied to a battery power supply for a computer, the series of warnings enable the computer operator to transfer data from a temporary memory to permanent storage in the time interval between a warning signal and computer shutdown; and since computer shutdown is effected before the battery is fully discharged a battery-destructive phenomenon known as a polarity cell reversal is prevented. The battey monitoring and management techniques disclosed comprise generating periodically at a first rate a voltage-discharge value (SS) indicative of the rate of change of battery discharge voltage with respect to the elapse of time while the battery power supply is under load, generating periodically at the first rate a compensation-factor value (CF) which is numerically larger in absolute value than the absolute value of SS during at least the initial portion of the startup voltage depression and which is thereafter periodically decremented at a second rate until CF reaches a predetermined fixed value (FCF) approaching the SS of the stable section of the voltage discharge curve, and generating periodically at the first rate a real-time compensated voltage-discharge value (CSAV) in accordance with the functional expression: ##EQU1## The real-time CSAV(s) determine the particular battery management step taken.

Growing community of inventors

St. Joseph, MI, United States of America

Saifee Fakruddin