Browse Prior Art Database

3-Mode Small Computer System Interface Terminator

IP.com Disclosure Number: IPCOM000114137D
Original Publication Date: 1994-Nov-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Isoda, H: AUTHOR [+2]

Abstract

This article relates to Small Computer System Interface (SCSI) which is to be installed into a Notebook PC, particularly to 3-Mode SCSI Terminator which has additional feature when the PC operates in low power mode. In the low power mode, output current to SCSI signal lines are reduced while keeping the SCSI termination effect.

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3-Mode Small Computer System Interface Terminator

      This article relates to Small Computer System Interface (SCSI)
which is to be installed into a Notebook PC, particularly to 3-Mode
SCSI Terminator which has additional feature when the PC operates in
low power mode.  In the low power mode, output current to SCSI signal
lines are reduced while keeping the SCSI termination effect.

      The SCSI termination is electrically controlled in response to
its current mode among low power mode, high power mode and disconnect
(power down) mode.

      The Figure shows the circuit diagram for N-lines SCSI signals.
The input of ON/OFF signal operates for disconnect mode while SCSI
signals lines are completely isolated from the termination circuit.
The disconnect mode is useful when SCSI devices are inactive, in
sleep or in power-down status.

      The input of LOW/HIGH signal makes the PC to low power or high
power mode.  The low power mode is intended to drive short lines of
SCSI signals.  This is effective for battery operating personal
computers which integrates SCSI devices internally.

      The high power mode provides the SCSI maximum current.  This is
applicable when SCSI devices are connected externally, typically in
office environment where AC power is available to personal computers.

      Large power consumption by SCSI terminator has been a demerit
when SCSI sub-system is installed into Laptops/Notebooks where low
voltage battery operatio...