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# Power Management Effect Indicator

IP.com Disclosure Number: IPCOM000106390D
Original Publication Date: 1993-Nov-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 50K

IBM

## Related People

No, M: AUTHOR [+3]

## Abstract

Disclosed is a personal computer system that calculates and displays how much power reduction has been accomplished by use of idle power-down timers commonly in use in battery operated portable personal computers to conserve power consumption of peripheral devices such as the Liquid Crystal Display (LCD) panel and fixed disk.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 76% of the total text.

Power Management Effect Indicator

Disclosed is a personal computer system that calculates and
displays how much power reduction has been accomplished by use of
idle power-down timers commonly in use in battery operated portable
personal computers to conserve power consumption of peripheral
devices such as the Liquid Crystal Display (LCD) panel and fixed
disk.

The power consumption characteristics of the peripheral devices
with a power saving state and an idle power-down timer may be
expressed by the following state transition model shown in Fig.1.

If a program caused such a device to operate with Tj seconds
interval (j=1,2,...), the power consumption P(T) under the timer
value T can be given by the following formula:

P(T) = P - SUM (I0-I1) x (Tj-T-K)     ...(1)
T=<Tj

Where P is a constant term independent of the timer value T, K =
(Iw+Is)xTs/(I0-I1), Iw being the power consumption of the rest of the
system during the transition from standby state to idle state.  Thus
the power reduction effect can be determined by calculating the
second term in the formula (1) from the usage data Tj (j=1,2,..) and
the system's power characteristics (I0, I1, Is, Ts, Iw).

Fig.2 is an example of this system applied to the LCD panel:

The video controller (A) and keyboard controller (C) detect
screen update and user input request, respectively, and inform the
microcontroller (B) through the...