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Reduced Power Consumption for Monitors when Operating in Power Save Modes

IP.com Disclosure Number: IPCOM000117434D
Original Publication Date: 1996-Feb-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Duddridge, G: AUTHOR

Abstract

When a monitor with a simple primary power supply is switched from the operating condition to a power save mode, there is a tendency for the secondary voltages to rise causing an unwanted increase in power consumption.

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This is the abbreviated version, containing approximately 65% of the total text.

Reduced Power Consumption for Monitors when Operating in Power Save
Modes

      When a monitor with a simple primary power supply is switched
from the operating condition to a power save mode, there is a
tendency for the secondary voltages to rise causing an unwanted
increase in power consumption.

      A solution to the above problem is to increase the DC voltage
gain of the power supply control system, under start up and some
power save operating conditions.  This is achieved by utilizing a
synchronization signal which controls the operating frequency of the
power supply, as a control signal which electronically switches a
resistive gain determining element out of the PSU voltage control
circuit when the monitor is in full operation.  This has the
beneficial effects of:
  1.  Reducing the operating voltage rating of the PSU secondary side
       electrolytic capacitors.
  2.  Reducing the power supply transient load demand when the
monitor
       is first switched into operation.
  3.  Reducing the power supply transient load demand when the
monitor
       is switched from some power save modes of operation into full
       screen activity.
  4.  Reducing the monitor power consumption when operating in power
       save modes.

      In the Figure, the PSU o/p voltage is controlled by comparing a
fraction of the sense voltage derived from T100, rectified by CR130
and filtered by C130 and divided by R120, RV100, R126 and...