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Automatic Power Control for Integral Computer/Monitor System

IP.com Disclosure Number: IPCOM000115026D
Original Publication Date: 1995-Mar-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 85K

Publishing Venue

IBM

Related People

Jackson, FS: AUTHOR

Abstract

Integrated Computer/Monitor systems may utilise a low voltage power switch control mechanism such as that of the personal computer planar. The power supply of such a planar has no mains switch. Instead, it is controlled by its load - the computer system. The computer monitors a low voltage user-operated switch which indicates that the user wishes to power down the computer system. On receipt of the Power-Down signal, the computer proceeds to "clean-up" its currently running applications to prepare for an orderly shut down, and follows by sending a signal to its power supply to shut down into sleep mode. In this mode, the power supply delivers only sufficient power to facilitate a recovery power-up procedure, on detection of the next operation of the user's switch.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Automatic Power Control for Integral Computer/Monitor System

      Integrated Computer/Monitor systems may utilise a low voltage
power switch control mechanism such as that of the personal computer
planar.  The power supply of such a planar has no mains switch.
Instead, it is controlled by its load - the computer system.  The
computer monitors a low voltage user-operated switch which indicates
that the user wishes to power down the computer system.  On receipt
of the Power-Down signal, the computer proceeds to "clean-up" its
currently running applications to prepare for an orderly shut down,
and follows by sending a signal to its power supply to shut down into
sleep mode.  In this mode, the power supply delivers only sufficient
power to facilitate a recovery power-up procedure, on detection of
the next operation of the user's switch.

      With such a computer power control system employed in an
integrated computer/monitor system, the computer section, or pod,
requires a control signal from the monitor.  This signal may be
derived from one of the monitor's DC power supply lines and delivered
to the pod via either a flying lead/plug/socket arrangement, or a
mating plug and socket pair, mechanically attached to the monitor and
pod respectively.

This is undesirable for the following reasons:
  1.  The cost of cable, plug and socket or mechanically fixed plug
       and socket is relatively high.
  2.  Plug and socket arrangements usually significantly degrade
       reliability.
  3.  Export of signals or power lines from the monitor involves
       meeting SELV (Safety Extremely Low Voltage) regulations.
These
       include stringent voltage isolation and current limit
       requirements and may adversely impact the monitor's artwork
and
       circuit designs.
  4.  Introduction of additional hard-wired links between monitor and
       computer systems may adversely impact system EMC performance.
       Such wiring may pick up radiation from many possible sources
       within the monitor and/or computer and radiate this directly,
       and/or conduct it into the other system, from which it is then
       radiated.  Typically, common-mode ferrite beads are required
to
       isolate connected systems at radio frequencies.  These are
       generally expensive it...