US 5,349,688 AGranted

Method for reducing power consumption includes comparing variance in number of times microprocessor tried to read input in predefined period to predefined variance

AssigneeChips and Technologies, Inc.

InventorAu H. Nguyen

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Abstract

Two methods and apparatus for reducing power consumption in battery powered computers are disclosed. The first places the computer in a sleep mode whenever a certain data input function is called. The second applies statistical analysis to calls to another data input function. By measuring the number of times the computer has tried to read data from the keyboard over the past predefined period, the variance between the high and low number of calls over the present and preceding time periods, and whether the number of times the computer has tried to read data has both exceeded the present limit and remained within the preset variance limit for a predefined minimum time, the desirability of activating a sleep mode for the computer can be determined.

Claims19

Dependent claims

A method for placing a microprocessor, having a clock generating a clock frequency, into a sleep state while the microprocessor waits for data input from a keyboard, the method being performed in a system controller coupled to said microprocessor and comprising the steps of:

(a) counting a number of times the microprocessor has tried to read data from the keyboard in a predefined amount of time;
(b) comparing said number of times the microprocessor tried to read data in the predefined amount of time with a predefined minimum number;
(c) comparing the variance in said number of times the microprocessor tried to read data in a predefined amount of time to a predefined variance amount, if a number of tries exceeded said predefined minimum number;
(d) comparing a length of time that both said number of times the microprocessor tried to read data exceeded said predefined minimum number and the result was less than the predefined variance to a predefined minimum time if the variance was less than the predefined variance;
and
(e) placing the computer into a sleep state if the length of time exceeded the minimum time, wherein in said sleep state, the clock stops generating the clock frequency.

3 more elements

(a) determining whether said microprocessor is presently in said sleep state;
(b) determining whether said sleep state can be invoked if said microprocessor is not presently in said sleep state;
(c) counting a number of time the microprocessor has tried to read data from the keyboard in a predefined amount of time if said sleep state can be invoked;
(d) comparing said number of times the microprocessor tried to read data in the predefined amount of time with a predefined minimum number;
(e) comparing said number of times the microprocessor tried to read data in the predefined amount of time with a predefined maximum number;
(f) comparing the variance in said number of times the microprocessor tried to read data in a predefined amount of time to a predefined variance amount, if a number of tries exceeded said predefined minimum number and was less than said predefined maximum number;
(g) comparing a content of an idle interval counter to a predefined idle interval number if said variance was less than the predefined variance;
and
(h) placing the computer into a sleep state wherein said clock frequency is stopped or reduced if said content exceeds said predefined idle number.

6 more elements

Dependencies are inferred from the claim text.