Browse Prior Art Database

Shutdownless Charge/Discharge Circuit in a Notebook PC

IP.com Disclosure Number: IPCOM000115218D
Original Publication Date: 1995-Apr-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Narita, I: AUTHOR [+2]

Abstract

Disclosed is a discharge/charge circuit in a notebook PC which never shuts down even when detaching the battery during the discharge mode. In general, the discharge mode is used to cancel the memory effect of the main battery. During this mode, the power is supplied from the main battery instead of the AC/DC adapter to discharge the battery even though the AC/DC adapter is attached. In any other mode, the power is supplied from the AC/DC adapter if the AC/DC adapter is attached. So, the user is likely to think that the PC is powered by the AC/DC adapter, and therefore he/she maybe detaches the main battery during the discharge mode. With the conventional circuit of the notebook PC, the system shuts down in response to detaching the battery because of no power supply.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 65% of the total text.

Shutdownless Charge/Discharge Circuit in a Notebook PC

      Disclosed is a discharge/charge circuit in a notebook PC which
never shuts down even when detaching the battery during the discharge
mode.  In general, the discharge mode is used to cancel the memory
effect of the main battery.  During this mode, the power is supplied
from the main battery instead of the AC/DC adapter to discharge the
battery even though the AC/DC adapter is attached.  In any other
mode, the power is supplied from the AC/DC adapter if the AC/DC
adapter is attached.  So, the user is likely to think that the PC is
powered by the AC/DC adapter,  and therefore he/she maybe detaches
the main battery during the discharge mode.  With the conventional
circuit of the notebook PC, the system shuts down in response to
detaching the battery because of no power supply.  To prevent from
the shutdown, some protection mechanism and/or method is desired.

      According to this invention, the power is backed up by the
AC/DC adapter when the user detaches the main battery during the
discharge mode and there is no concern of the system shutdown.

       Fig. 1 is the conventional charge/discharge circuit.  The
operation during the discharge mode is as follows:
  1.  SW1 is set to OFF and SW2 is set to ON by the each control
       circuit.
  2.  Main battery supplies the power to the DC/DC converter until
the
       voltage of the battery becomes to the certain voltage which
can...