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A power saving method in suspend mode for controllers which have multiple operating points

IP.com Disclosure Number: IPCOM000016426D
Original Publication Date: 2003-Jan-10
Included in the Prior Art Database: 2003-Jun-21
Document File: 2 page(s) / 129K

Publishing Venue

IBM

Abstract

Disclosed is a power saving method for the controllers which has multiple operating points and can not be powered off during suspend mode (i.e. stand-by mode or ACPI S3 state) by setting the voltage of the controllers at minimum in the suspend mode

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  A power saving method in suspend mode for controllers which have multiple operating points

  Some of the controllers used in the notebook computers have multiple operating frequencies which correspond to each operating voltage.

When higher performance is required, the controllers operate at higher frequency and at higher voltage and when longer battery life is required, they operate at lower frequency and at lower voltage. Some of these controllers have to be powered on during the suspend mode and even though the frequency is 0MHz, the power consumption is not 0W because of its leakage current. To minimize this leakage current, the supply voltage should be reduced. By setting the voltage of the controllers at minimum guaranteed voltage in the suspend mode, the leakage current can be reduced and can maximize the battery life in the suspend mode without connecting to AC power.

C ontroller is in the operating m ode

VCC(V0,V1,V2.....Vn-1)

Controller

Fn-1>.....>F2>F1>F0

Vn-1>.....>V2>V1>V0

Mode0(F0,V0) Mode1(F1,V1) Mode2(F2,V2)

Mode n-1(Fn-1,Vn-1)

........

More Performance More Power

VCC

(V0)

Controller is in the suspend m ode

Clock Frequency = 0 MHz

Controller

Suspend Mode(0MHz,V0)

Fn-1>.....>F2>F1>F0>0
V
n-1>.....>V2>V1>V0>0

Fig. 1

1

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Fig. 2

The controllers mentioned here are defined as follows:
(a) The controllers have more than two operating points and change operating frequencies and voltages for the...