# US 7,412,614 B2 · Power management using a pre-determined thermal characteristic of a memory module

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- Number: US 7,412,614 B2
- Document ID: US7412614B2
- Status: Granted
- Kind: B2
- Application number: 10/836,018
- Filed: 2004-04-29
- Published: 2005-11-03
- Granted: 2008-08-12
- Earliest claimed: 2004-04-29
- Assignees: Hewlett-Packard Development Company, L.P.
- Inventors: Joesph W. Ku
- Web page: https://patentgrep.com/patent/US7412614B2

## CPC

- G06F 1/206: {comprising thermal management}
- Y02D 10/00: Energy efficient computing, e.g. low power processors, power management or thermal management
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

A computer system includes a memory module. Power management in the computer system is performed with at least one temperature rise parameter (ΔTx) of the memory module.

## Claims

### Claim 1

A method of estimating power dissipation in a computer system, the computer system including a memory module, the method comprising:
determining at least one temperature rise parameter of the memory module for a mode of operation;
estimating current drawn by the memory module during a mode of operation based at least on the temperature rise parameter for the mode of operation;
estimating the power dissipation of the memory module during the mode of operation based at least on the current drawn by the memory module during the mode of operation; and
accessing an absolute temperature limit for the memory module, the temperature rise parameter being used by accessing a value for the temperature rise parameter, summing the value with a value indicating ambient temperature, and comparing the sum to the temperature limit.

### Claim 2 (depends on 1)

The method of claim 1, wherein the memory module has multiple modes of operation; and wherein a plurality of different temperature rise parameters are used for different modes.

### Claim 3 (depends on 1)

The method of claim 1, wherein a value for each parameter is estimated from current drawn during a specific mode, memory supply voltage, and case thermal resistance.

### Claim 4 (depends on 1)

The method of claim 1, wherein the memory module includes at least one serial presence device, and wherein the determining includes accessing at least one temperature rise parameter from the at least one serial presence device.

### Claim 5 (depends on 1)

The method of claim 1, wherein one mode of operation is system bootup.

### Claim 6 (depends on 1)

The method of claim 1, further comprising taking steps to reduce power dissipation in the memory module, the steps taken in response to the comparison.

### Claim 7 (depends on 1)

The method of claim 1, wherein different temperature rise parameter values are determined for different modes of operation of the memory module; and wherein each parameter value is used in a comparison to an absolute temperature limit of the memory module.

### Claim 8 (depends on 1)

The method of claim 1, wherein estimating the power dissipation further comprises applying estimated current to the memory module based on an application that uses the memory module.

### Claim 9 (depends on 8)

The method of claim 8, wherein the current draw is derived by calculating statistics of current draw while certain software applications are running.

### Claim 10 (depends on 8)

The method of claim 8, wherein the current draw is learned during startup of the application.

### Claim 11 (depends on 8)

The method of claim 8, wherein estimating the current draw includes sampling and calculating statistic of the current draw while the application is running.

### Claim 12 (depends on 11)

The method of claim 11, further comprising measuring system temperatures during normal operation of the computer, and comparing the measured system temperatures to an absolute temperature limit.

### Claim 13 (depends on 1)

The method of claim 1, wherein the temperature rise parameter is determined during normal operation of the computer system.

### Claim 14

A method of performing power management in a computer system with respect to an application, the computer system including a memory module, the method comprising:
computing the current draw of the memory module for a mode of operation based on at least one pre-determined value for temperature rise of the memory module for the mode of operation;
using the current draw of the memory module for the mode of operation to estimate power dissipation of the memory module when the application is running; and
accessing an absolute temperature limit for the memory module, summing the value for temperature rise with a value indicating ambient temperature, and comparing the sum to the temperature limit.

### Claim 15 (depends on 14)

The method of claim 14, wherein at least one value for temperature rise is estimated from current draw of the memory module for a mode of operation, memory supply voltage, and case thermal resistance.

### Claim 16 (depends on 14)

The method of claim 14, further comprising reducing power dissipation in the memory module in response to the comparison.

### Claim 17 (depends on 14)

The method of claim 14, wherein different temperature rise parameter values are accessed for different modes of operation of the memory module; and wherein each parameter value is used in a comparison to an absolute temperature limit of the memory module.

### Claim 18

A computer comprising:
a memory module;
computer-readable memory encoded with power management software for:
determining a value for at least one temperature rise parameter of the memory module;
computing the current draw of the memory module for a mode of operation based on the value for temperature rise of the memory module for the mode of operation;
using the current draw of the memory module for the mode of operation to estimate power dissipation of the memory module when the application is running; and
accessing an absolute temperature limit for the memory module, calculating the temperature rise based on a value for the temperature rise parameter, summing the temperature rise with a value indicating ambient temperature, and comparing the sum to the temperature limit.

### Claim 19 (depends on 18)

The computer of claim 18, wherein a value for each temperature rise parameter is estimated based on at least one of memory supply voltage and case thermal resistance.

### Claim 20 (depends on 18)

The computer of claim 18, wherein different temperature rise parameter values are accessed for different modes of operation of the memory module; and wherein each parameter value is used in a comparison to an absolute temperature limit of the memory module.