Browse Prior Art Database

Power Source Control Method for Expansion Box

IP.com Disclosure Number: IPCOM000104660D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Kamijoh, K: AUTHOR [+3]

Abstract

Disclosed is a power source and an ON/OFF control method for an expansion box of a notebook PC. For this control, three signals are added onto the external bus of the notebook PC.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 99% of the total text.

Power Source Control Method for Expansion Box

      Disclosed is a power source and an ON/OFF control method for an
expansion box of a notebook PC.  For this control, three signals are
added onto the external bus of the notebook PC.

      Fig. 1 shows a circuit of the notebook PC.  Three signals, 1
through 3, are on the external bus.  Signal 1 is the output disable
signal to power supply unit in the notebook PC.  Signal 2 is the
power-on signal from the notebook PC to the expansion box.  Signal 3
is the power-on signal from the expansion box to the notebook PC.  A
switch 4 is a main switch on the notebook PC and a switch 5 is a
sub-switch to support the expansion box.  The switch 5 is normally
ON.  However, when the expansion box is attached to the notebook PC,
the switch 5 should be OFF.

      Fig. 2 through Fig. 4 show a connection between the notebook PC
and three types of the expansion box, respectively.  In these
figures, the double lines show the power supply pass to logics.  In
Fig. 2, the notebook PC supplies power to the whole system include
the expansion box.  In Fig. 3, the power output from the notebook PC
is disabled and the expansion box supplies power.  In Fig. 4, the
notebook PC and the expansion box supply power to themselves.

      In these figures, the switch 4 is a mechanical switch and
controls power on/off of the whole system.  However, the power-on
signals can be controlled by a software or another switch in the
expansi...