(12) United States Patent
`Peters et al.
`
`USOO6470289B1
`(10) Patent No.:
`US 6,470,289 B1
`(45) Date of Patent:
`Oct. 22, 2002
`
`(54) INDEPENDENTLY CONTROLLING PASSIVE
`AND ACTIVE COOLING IN A COMPUTER
`SYSTEM
`
`(75) Inventors: Mark W. Peters, Houston; Richard H.
`Hodge, The Woodlands, both of TX
`(US)
`(73) Assignee: Compaq Information Technologies
`Group, L.P., Houston, TX (US)
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`y
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/368,950
`(22) Filed:
`Aug. 5, 1999
`(51) Int. Cl. .................................................. G01K 3/08
`(52) U.S. Cl. .......................................... 702/132; 374/10
`(58) Field of Search ................................. 702/130, 131,
`702/132, 133,99; 374/10, 11, 100, 103,
`112, 113, 114, 120, 145, 163; 361/158;
`713/300
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`5,566,377 A * 10/1996 Lee ........................... 165/80.3
`5,731,954. A * 3/1998 Cheon ...
`... 165/104.33
`5,805,403 A
`9/1998 Chelma ...................... 337/302
`6,134,667 A * 10/2000 Suzuki et al......
`... 318/302
`6,172,611 B1 * 1/2001 Hussain et al. ...
`... 340/584
`6,204,623 B1 * 3/2001 Levy et al. ....
`... 318/641
`6.243,656 B1 * 6/2001 Arai et al. .
`... 702/132
`6,321,175 B1 * 11/2001 Nagaraj...................... 257/467
`
`OTHER PUBLICATIONS
`
`Intel(R) Corporation, AP-825, Application Note, Apr. 1998,
`Order Number 243724-001.
`
`(List continued on next page.)
`
`Primary Examiner Marc S. Hoff
`Assistant Examiner Edward Raymond
`(74) Attorney, Agent, or Firm-Conley, Rose & Tayon,
`P.C.; Michael F. Heim; Jonathan M. Harris
`(57)
`ABSTRACT
`
`A computer System having thermal control logic that effi
`ciently cools the computer System. In accordance with one
`embodiment of the invention, the thermal control logic
`couples to a CPU module and a fan. The CPU module
`includes a pair of temperature response elements. One
`temperature response element located near or on the CPU
`core logic or die on which the CPU is fabricated. The other
`temperature response element is located near or on an
`exterior Surface of the CPU module. The thermal control
`logic monitors the temperature of recorded by each tem
`perature response element and controls the Speed of the fan
`and the frequency of the CPU core clock independently.
`Preferably, the thermal control logic adjusts the fan Speed as
`a function of the temperature recorded by the temperature
`element adjacent an exterior surface of the CPU module.
`The thermal control logic also adjusts the frequency of the
`CPU clock signal as a function of the temperature recorded
`by the temperature response element adjacent the CPU core.
`By disasSociating control of the fan Speed from the tem
`perature of the CPU core, the annoyance in conventional
`computer Systems caused fans that rapidly turn on and off or
`change Speed rapidly is reduced.
`
`Mobile Pentium(E) II Processor and Pentium II Processor
`Mobile Module Thermal Sensor Interface Specifications,
`
`39 Claims, 4 Drawing Sheets
`
`170
`
`O2
`
`105
`
`E.
`
`g
`S
`s
`
`MAN MEMORY -124
`s
`s
`-128
`|
`420
`
`ev
`R
`BRIDGE
`
`121
`
`AGP
`
`/ OO
`
`23
`
`125
`
`GRAPHICS
`CONTROLER
`126
`
`FAN
`CONTROLLER
`
`180
`
`161
`
`AC
`CONDITIONER
`
`162
`
`PC BUS Die
`F-132
`SOUTH
`31
`BRIDGE
`CLK REG.
`
`130
`
`140
`
`ISA BUS
`
`KBC
`
`BOS
`ROM
`
`
`
`172
`
`POWER SUPPLY 64
`
`LENNOX EXHIBIT 1007
`Lennox Industries Inc. v. Rosen Technologies LLC, IPR2023-00715, Page 1
`
`

`

`US 6,470,289 B1
`Page 2
`
`OTHER PUBLICATIONS
`System Management Bus Specification, Smart Battery Sys
`tem. Specifications, Revision 1.1, Dec. 11, 1998, CopyrightC)
`1996, 1997, 1998, Benchmarq Microelectronics Inc., Dura
`cell Inc., Energizer Power Systems, Intel Corporation, Lin
`ear Technology Corporation, Maxim Integrated Products,
`Mitsubishi Electric Corporation, National Semiconductor
`Corporation, Toshiba Battery Co., Varta Batterie AG.
`Mobile Pentium(E) II Processor In Mini-Cartridge Package
`At 366 MHZ, 300 PE MHZ, and 266 PE MHZ, Intel(R)
`Corporation, Order Number: 245108-001.
`
`Computer Fan Speed System. To Reduce Audible Percepti
`bility Of Fan Speed Changes, Charles J. Stancil et al., U.S.
`Patent Application Ser. No. 09/443,575, filed Nov. 19, 1999
`(23 p.).
`Adaptive Fan Controller For A Computer System, Gregory
`P. Ziarnik, U.S. Patent Application Ser. No. 10/036,273, filed
`Dec. 26, 2001 (24 p.).
`Low Cost PC Temperature Monitor And Fan Control ASIC,
`Analog Devices, Preliminary Technical Data, ADM 1022,
`Rev. PrJ Mar. 1999 (20 pp.).
`* cited by examiner
`
`LENNOX EXHIBIT 1007
`Lennox Industries Inc. v. Rosen Technologies LLC, IPR2023-00715, Page 2
`
`

`

`U.S. Patent
`
`Oct. 22, 2002
`
`Sheet 1 of 4
`
`US 6,470,289 B1
`
`
`
`CE|EldS NW/-|Ol9O7
`
`XOOTO
`
`TOÀNINOO
`
`|
`
`AJOSNES
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`LENNOX EXHIBIT 1007
`Lennox Industries Inc. v. Rosen Technologies LLC, IPR2023-00715, Page 3
`
`

`

`U.S. Patent
`
`US 6,470,289 B1
`
`AðJOWE W NIWW
`
`EM, BU
`~
`
`
`
`
`
`
`
`CPU CLOCK
`
`LENNOX EXHIBIT 1007
`Lennox Industries Inc. v. Rosen Technologies LLC, IPR2023-00715, Page 4
`
`

`

`U.S. Patent
`
`Oct. 22, 2002
`
`Sheet 3 of 4
`
`US 6,470,289 B1
`
`LOW
`TEMP.
`
`HIGH
`TEMP.
`
`FAN
`209
`SPEED -1
`
`FIG.4
`
`FIG.5
`
`201
`
`2O1
`
`201
`
`201
`
`211
`
`211
`
`211
`
`211
`
`FIG.6
`
`
`
`
`
`
`
`
`
`TEMP.
`
`HIGH
`TEMP.
`
`CPU
`SPEED
`
`213
`u?
`216
`
`95
`
`99
`
`110
`
`LOW
`TEMP.
`
`HIGH
`TEMP.
`
`CPU
`SPEED
`
`u?? 17
`
`LENNOX EXHIBIT 1007
`Lennox Industries Inc. v. Rosen Technologies LLC, IPR2023-00715, Page 5
`
`

`

`U.S. Patent
`
`Oct. 22, 2002
`
`Sheet 4 of 4
`
`US 6,470,289 B1
`
`300
`
`302
`
`
`
`
`
`
`
`
`
`
`
`
`
`KBC POLLS CPU FOR
`TEMPERATURE
`READINGS
`
`KBC COMPARES CURRENT
`TEMPERATURES TO
`RANGE
`
`RANGE
`EXCEEDED?
`
`KBC ASSERTS SM
`
`
`
`
`
`CPU DETERMINES WHICH SENSOR
`TRIGGERED SM AND DETERMINES
`NEW CPU SPEED AND/OR FAN SPEED
`
`
`
`
`
`
`
`CPU INITATES APPLICABLE CHANGE
`IN CPU SPEED (THROTTLING) OR
`FAN SPEED
`
`KBC LOADED WITH HIGH AND LOW
`TEMPERATURE VALUES OF
`NEW RANGE
`
`FIG.7
`
`LENNOX EXHIBIT 1007
`Lennox Industries Inc. v. Rosen Technologies LLC, IPR2023-00715, Page 6
`
`

`

`US 6,470,289 B1
`
`1
`INDEPENDENTLY CONTROLLING PASSIVE
`AND ACTIVE COOLING IN A COMPUTER
`SYSTEM
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`2
`Most ICS used in computer Systems include transistors.
`CPUs include thousands or hundreds of thousands of tran
`Sistor in a single package. Each transistor generally acts as
`a Switch and operates in one of two States-conducting and
`not conducting. Most computer-related ICS are made from a
`type of Semiconductor technology called Complementary
`Metal Oxide Semiconductor (“CMOS”). Most of the elec
`trical current flowing through transistors, such as CMOS
`transistors, flows while the transistor changes States from
`conducting to non-conducting or Vice versa. While the
`transistor is in a particular State, Such as conducting or
`non-conducting, little, if any, current flows through the
`device.
`The transistors in a computer IC change State Synchro
`nously with a clock signal. Thus, the transistors in a 400
`MHz CPU (i.e. a CPU operating from a 400 MHz clock
`Signal), change State 800 million times per Second. Of
`course, not every transistor in the CPU changes State on
`every edge of every cycle of the clock signal; Some or many
`transistors may remain in a given State for multiple clock
`Signals. Nevertheless, because current flows through the
`transistors, which may number in the hundreds of thousands
`or millions in a typical CPU, on the edges of the clock signal,
`current flows in spurts 800 millions times per second for a
`400 MHz CPU. As the operating speeds of CPUs have
`increased (i.e., higher frequency clock signals), and likely
`will continue to increase, the current flowing the CPU has
`and will continue to increase, all else being equal.
`Accordingly, heat generated by current flowing in a CPU has
`become a problem. CPU designers strive to reduce the
`operating current requirement of their CPUs, but additional
`measures usually are desirable to reduce the heat generated
`by the CPU.
`The passive cooling technique includes reducing the clock
`frequency of the CPU. Instead of operating at 400 MHz, the
`CPU clock will be reduced to lower frequency, such as 300
`MHz. With fewer transistor state changes occurring per
`second, less current flows through the CPU each second and
`thus, leSS heat it is generated by the device.
`Although the principles of the present invention explained
`below apply to cooling either a desktop or portable (laptop)
`computer, the benefit is more pronounced with regard to
`laptop computers. Laptops operate either from power Sup
`plied from a wall Socket, alternating current (“AC) power,
`or from a battery, direct current (“DC) power. Typically, the
`battery is a rechargeable battery that, with a full charge, can
`power the computer for Several hours depending on oper
`ating conditions. Because a battery's charge only operates
`the computer for a relatively short period of time, it is highly
`desirable to design laptops to consume as little power as
`possible.
`In contrast to desktop computers, the fans in laptops often
`can be controlled by the computer's internal logic thereby
`permitting the lap top computer to turn off the fan during
`periods of time in which the fan is not needed to actively
`cool the computer. Some laptops, in fact, include a tempera
`ture Sensor to permit monitoring the temperature inside the
`computer. Further, a temperature Sensor is incorporated into
`some CPUs, such as the Mobile Pentium(R II CPU by Intel(R)
`to permit monitoring of the internal temperature of the CPU.
`Monitoring the internal temperature of the CPU generally is
`regarded as beneficial because the CPU is a major contribu
`tor to the total heat generated by a computer's electronics.
`Conventional laptop computers typically monitor the
`computer's temperature and turn the fan on or off while
`concurrently adjusting the CPU clock Speed. Many conven
`
`25
`
`Not applicable.
`STATEMENT REGARDING FEDERALLY
`SPONSORED RESEARCH OR DEVELOPMENT
`Not applicable.
`BACKGROUND OF THE INVENTION
`15
`1. Field of the Invention
`The present invention generally relates to cooling a com
`puter System. More particularly, the present invention relates
`to passively and actively cooling a computer System. Still
`more particularly, the invention relates to independently
`controlling passive and active cooling in a portable com
`puter in response to processor temperature.
`2. Background of the Invention
`Computer Systems include numerous electrical compo
`nents that draw electrical current to perform their intended
`functions. A computer's microprocessor or central proceSS
`ing unit (“CPU”) requires electrical current to perform many
`functions Such as controlling the overall operations of the
`computer System and performing various numerical calcu
`lations. Any electrical device through which electrical cur
`rent flows produces heat. The amount of heat any one device
`generates generally is a function of the amount of current
`flowing through the device.
`Typically, each manufacturer designs its products to oper
`ate correctly within a predetermined temperature range. If
`the temperature exceeds the predetermined range (i.e., the
`device becomes too hot or too cold), the device may not
`function correctly thereby potentially degrading the overall
`performance of the computer System. Thus, it is desirable for
`a computer System generally and its components specifically
`to operate within a thermally benign environment.
`Some computers implement two techniques for cooling
`the computers internal electrical components. One
`technique, referred to as “active' cooling, uses a fan to blow
`warm air Surrounding one or more “hot” components
`through a vent and outside the computer. Thus, active
`cooling removes the warm air from a computer.
`The Second cooling technique, called “passive' cooling,
`Slows down the operating Speed of a component So that the
`component will produce leSS heat. This concept is analogous
`to a human that travels by foot a given distance. Running the
`distance at fall Speed causes the person to become hotter
`than merely walking the same distance at a slow pace. To
`filly appreciate active cooling in a computer, consider that
`many electrical components, Such as integrated circuits
`(“ICs”) operate using a "clock” signal. A clock signal is a
`Voltage that changes rapidly between a high Voltage level
`(e.g., 3.3 volts) and a low voltage level (e.g., 0 volts) at a
`predetermined rate. Each transition is called an "edge.” The
`transition of the voltage from low to high and back to low
`again is called a “cycle” and the number of cycles per Second
`is called “frequency' which is measured in units of Hertz
`(“Hz'). For example, a 400 megahertz (MHz) clock signal
`oscillates at a rate of 400 million cycles per Second. Because
`each cycle includes two voltage transitions (one from low to
`high and the other from high back to low), a 400 MHz clock
`Signal changes Voltage State 800 million times per Second.
`
`65
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`LENNOX EXHIBIT 1007
`Lennox Industries Inc. v. Rosen Technologies LLC, IPR2023-00715, Page 7
`
`

`

`US 6,470,289 B1
`
`15
`
`25
`
`35
`
`3
`tional laptops monitor the CPU internal temperature and Set
`the State of the fan (i.e., on or off) and at the same time adjust
`the clock frequency. While generally Sufficient to maintain
`the computer operating in a benign thermal environment,
`this technique in which the passive and active cooling States
`are controlled together dependent upon a single temperature
`reading Suffers from at least one problem as explained
`below.
`The problem is most pronounced in laptops which, as
`noted above, have a limited battery operating life. To con
`Serve battery life, laptops often keep the fan off as much as
`possible to conserve battery power. That is, whenever not
`needed for cooling, the computer turns off the fan and when
`needed, the computer turns on the fan. Of course, the
`computer also adjusts the CPU clock frequency as it adjusts
`the fan. The internal temperature of a CPU can vary rapidly
`as its clock frequency changes. In computers that monitor
`internal CPU core temperature and that turn the fan on and
`off and simultaneously adjust CPU clock frequency in
`response to CPU core temperature, the fan will be turned on
`and off at an annoying rapid rate because the CPU core
`temperature can vary rapidly. The annoyance is to the user
`who can hear the fan turn on and off. On the other hand, if
`the computer monitors the temperature away from the CPU
`core, Such as on an exterior Surface of the CPU package, to
`avoid the cycling of the fan on and off So rapidly, the
`computer may unnecessarily slow down the CPU clock to
`correct a thermal problem that is unrelated to the CPU core.
`An additional problem with laptops that control the fan
`and CPU clock frequency together in response to CPU
`internal temperature is that air blowing over a CPU gener
`ally does not effectively cool a CPU that becomes exces
`Sively warm because of internal transistor State changes. In
`other words, a CPU that becomes hot due to heat generated
`by its internal core logic is not cooled nearly as well by
`active cooling from a fan, but rather is cooled much more
`efficiently by passively adjusting the CPU clock frequency.
`Thus, often excessive battery power is used to run a fan that
`has little effect on correcting a thermal problem created by
`the CPU core.
`Accordingly, it is desirable to provide a computer with a
`thermal control System that Solves these problems. Such a
`computer will reduce or minimize the annoyance caused by
`a fan turning on and off often in a relatively short period of
`time. Further, Such a computer will have a thermal control
`mechanism that will effectively maintain the computer Suf
`ficiently cool using less power than previously required.
`
`40
`
`45
`
`BRIEF SUMMARY OF THE INVENTION
`The problems noted above are Solved in large part by a
`computer System having thermal control logic that effi
`ciently cools the computer System. In accordance with one
`embodiment of the invention, the thermal control logic
`couples to a CPU module and a fan. The CPU module
`includes a pair of temperature response elements. One
`temperature response element located near or on the CPU
`core logic or die on which the CPU is fabricated. The other
`temperature response element is located near or on an
`exterior Surface of the CPU module. The thermal control
`logic monitors the temperature of recorded by each tem
`perature response element and controls the Speed of the fan
`and the frequency of the CPU core clock independently.
`Preferably, the thermal control logic adjusts the fan Speed as
`a function of the temperature recorded by the temperature
`element adjacent an exterior surface of the CPU module.
`The thermal control logic also adjusts the frequency of the
`
`50
`
`55
`
`60
`
`65
`
`4
`CPU clock signal as a function of the temperature recorded
`by the temperature response element adjacent the CPU core.
`By disasSociating control of the fan Speed from the tem
`perature of the CPU core, the annoyance in conventional
`computer Systems caused fans that rapidly turn on and off or
`change Speed rapidly is reduced.
`The thermal control logic may be implemented using a
`keyboard controller that connects to the CPU via a bus, such
`as a System Management Bus (“SMBus”). The CPU
`includes a temperature Sensor that includes the temperature
`response element located near an exterior Surface of the
`CPU. The other temperature response element is located
`near the CPU core and connects to the temperature Sensor.
`The temperature Sensor includes a pair of registers for
`Storing the temperature values associated with each of the
`temperature response elements. The keyboard controller
`polls the CPU for the temperature values recorded by the
`two temperature response elements. When one of the current
`temperatures exceeds a predetermined threshold, the key
`board controller generates a System management interrupt
`(SMI) signal. The CPU core responds to the interrupt by
`determining which of the temperature response elements
`triggered the SMI. A pair of control tables preferably stored
`in main memory coupled to the CPU specify whether the
`CPU clock frequency should be adjusted in response to the
`thermal event or whether the fan speed should be adjusted.
`The CPU core compares the current temperature recorded by
`the temperature response element that detected the thermal
`event to the control tables and adjusts either the fan Speed or
`the CPU clock frequency accordingly.
`These and other benefits and features will become appar
`ent once the following description is reviewed.
`BRIEF DESCRIPTION OF THE DRAWINGS
`For a detailed description of the preferred embodiments of
`the invention, reference will now be made to the accompa
`nying drawings in which:
`FIG. 1 shows a block diagram of a computer System
`including thermal control logic in accordance with the
`preferred embodiment;
`FIG. 2 shows a more detailed block diagram of the
`computer system of FIG. 1;
`FIG. 3 shows a communication protocol for requesting
`the current temperature values of the CPU shown in FIG. 2;
`FIG. 4 shows a preferred temperature control table for
`controlling fan Speed dependent on the temperature of a
`region away from the CPU core;
`FIG. 5 shows a preferred temperature control table for
`setting CPU throttling dependent on CPU core temperature;
`FIG. 6 shows an alternative temperature control table to
`that of FIG. 5 that forces the computer system to adjust CPU
`clock throttling before adjusting fan Speed; and
`FIG. 7 shows a preferred method for independently con
`trolling the passive and cooling mechanisms in the computer
`System of FIG. 2 by monitoring the microprocessor's inter
`nal and external temperatures.
`NOTATION AND NOMENCLATURE
`Certain terms are used throughout the following descrip
`tion and claims to refer to particular System components. AS
`one skilled in the art will appreciate, computer companies
`may refer to a component by different names. This document
`does not intend to distinguish between components that
`differ in name but not function. In the following discussion
`and in the claims, the terms “including” and "comprising
`
`LENNOX EXHIBIT 1007
`Lennox Industries Inc. v. Rosen Technologies LLC, IPR2023-00715, Page 8
`
`

`

`S
`are used in an open-ended fashion, and thus should be
`interpreted to mean “including, but not limited to . . .
`. Also,
`the term “couple' or “couples” is intended to mean either an
`indirect or direct electrical connection. Thus, if a first device
`couples to a Second device, that connection may be through
`a direct electrical connection, or through an indirect elec
`trical connection via other devices and connections.
`The terms central processing unit (“CPU”) and “CPU core
`logic' are used in the following disclosure. Unless otherwise
`indicated, “CPU” is intended to refer to an electrical mono
`lithic package that includes the CPU core logic and other
`components as desired, Such as the temperature described
`below or cache memory. The CPU core logic generally
`includes most or all of the key logic to control the computer
`System.
`
`15
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`Referring now to FIG. 1, in accordance with the preferred
`embodiment, computer system 100 includes a central pro
`cessing unit (“CPU”), thermal control logic 108 and a fan
`180. The computer system 100 may include many other
`components not shown in FIG. 1, but those components
`having particular relevance to cooling the computer in
`accordance with the preferred embodiment are shown. The
`CPU 102 preferably includes CPU core logic 104 fabricated
`on a semiconductor die 105 in accordance with standard
`manufacturing techniques. The CPU 102 also includes a
`temperature sensor 106 and clock control logic 107. The
`CPU 102 may include other components as desired.
`In accordance with the preferred embodiment, the tem
`perature Sensor 106 is capable of measuring or otherwise
`determining the temperature of the die 105 and a region
`away from the die 105, such as an exterior region 109 of the
`CPU 102. Thus, the temperature sensor 106 senses tempera
`ture at two locations, or more if desired. AS Shown concep
`tually in FIG. 1, the temperature sensor 106 senses the
`temperature of the CPU die 105 using a temperature
`response element 114, preferably a thermally Sensitive sili
`con diode, thermally coupled to the CPU core 104 or die
`105. The temperature response element 114 thus is mounted
`adjacent to, in, on or near the die 105 to detect the tempera
`ture of the CPU core 104 or die 105. The location of
`temperature response element 114 is Such that the tempera
`ture of the CPU core 104 is detected. The temperature sensor
`106 drives a small current through the diode 114 and
`measures the Voltage generated across the diode by the
`current. The resulting Voltage, in part, is a function of the
`temperature of the diode and thus, using the Voltage the
`temperature Sensor 106 computes the temperature of the
`CPU die 105.
`The CPU 102 includes another temperature response
`element 116 (e.g., also thermally sensitive a Silicon diode)
`which preferably is contained within the temperature Sensor
`106. Further, the temperature sensor 106 preferably is
`mounted on or near an exterior Surface of the CPU 102 and
`thus the silicon diode 116 contained therein provides an
`indication of the temperature of an exterior region of the
`CPU package 102. The temperature sensor 106 receives
`Signals from Sensors 114, 116 and computes and Stores
`temperature values in internal registers (shown in FIG. 2).
`For the purpose of this disclosure, the temperature of the
`CPU die 105, measured using silicon diode 114, is referred
`to as the “CPU core temperature” or “die temperature.” The
`temperature of the exterior CPU 102 region is referred to as
`the “external temperature' or “temperature Sensor tempera
`
`25
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`US 6,470,289 B1
`
`ss
`
`6
`ture.” Generally, “external temperature” is intended to
`include a temperature reading of an area Separate from the
`CPU core and preferably near or at an exterior region of the
`CPU. Although thermal sensor 116 is included as part of the
`CPU package 102, the sensor 116 could be located apart
`from, but connected to, CPU 102. For example, sensor 116
`could be located anywhere on the computer's System board
`(not shown) and thus “external temperature” can refer to the
`temperature of a region of computer system 100 that is
`influenced very little, if any, by heat generated by the CPU
`core 104.
`CPU 102 can be any suitable processor that includes a
`temperature Sensor capable of measuring or determining
`temperature at two or more locations in, on or near the CPU.
`Examples of Suitable CPUs include various package Styles
`of the Mobile Pentium(E) II Processor Such as the Mini
`Cartridge, MMC1 and MMC2 packages. The CPU die 105,
`clock control logic 107, temperature response elements 114,
`116, and temperature sensor 106 preferably are included in
`a single integrated or monolithic package fabricated accord
`ing to known techniques.
`The clock control logic 107 receives an input CPU
`CLOCK signal and uses that input CPU CLOCK signal to
`generate another clock Signal 111 used to operate the CPU
`core 104. The frequency of the clock signal provided to the
`CPU core 104 may be the same or different from the
`frequency of the input clock Signal. Further, clock control
`logic 107 may use the input CPUCLOCK signal to generate
`and provide multiple clock signals to the CPU core 104.
`Referring still to FIG. 1, the thermal control logic 108
`reads the CPU's temperatures from the temperature sensor
`106 and, if necessary, adjusts the thermal control of the
`computer system 100. In accordance with the preferred
`embodiment, the thermal control logic 108 independently
`controls the CPU core clock frequency and the speed of fan
`180 in response to one or both of the temperature readings
`provided by the temperature sensor 106. By “independently”
`it is meant that the thermal control logic 108 can adjust CPU
`clock frequency, referred to as CPU “throttling,” without
`adjusting the fan Speed and Vice versa and that the control of
`CPU throttling is based on a different temperature response
`element than that which controls fan speed. Preferably, the
`level of CPU throttling is determined based on CPU core
`temperature and fan Speed is determined based on external
`temperature. If desired, however, thermal control logic 108
`can throttle up or down (i.e., increase or decrease the
`frequency of the clock signal provided to the CPU core 104),
`while concurrently or Simultaneously adjusting the Speed of
`fan 180 via a fan speed signal.
`Preferably, the thermal control logic 108 adjusts the CPU
`throttling as the temperature sensor 106 indicates that the
`CPU die temperature, detected by silicon diode 114, has
`exceeded a predetermined range. Accordingly, if the thermal
`control logic 108 determines that the temperature of CPU
`die 105 has increased beyond a predetermined upper
`threshold, the thermal control logic throttles down the CPU
`core 104 (i.e., decreases its clock frequency to cause the core
`to generate less heat). Conversely, as the CPU core tem
`perature decreases below another predetermined lower
`threshold, the thermal control logic 108 throttles up the CPU
`core 105 (i.e., increases its clock frequency to permit the
`core to operate faster). Changes to the CPU core clock
`frequency are made via the CLOCK CONTROL signal
`which is asserted by thermal control logic 108 to the clock
`control logic 107. The clock control logic 107 generates and
`provides the clock signal 111 to the CPU core 104 in
`accordance with the desired clock frequency indicated by
`
`LENNOX EXHIBIT 1007
`Lennox Industries Inc. v. Rosen Technologies LLC, IPR2023-00715, Page 9
`
`

`

`US 6,470,289 B1
`
`15
`
`7
`the CLOCK CONTROL signal. Thus, the thermal control
`logic 108 throttles up or down the CPU core 104 in response
`to the temperature of the CPU core 104 as detected by
`silicon diode 114 located in close proximity to CPU die 105.
`In addition, the thermal control logic 108 can adjust
`independently the speed of the fan 180. Increases in fan
`Speed results in a greater Volume of air moving through the
`computer System 100 and thus greater cooling effect than
`with a slower fan Speed. A slower fan Speed moves leSS air
`and thus has less of a cooling effect.
`In general, heat generated by the CPU core 104 propa
`gates outward through the CPU package. Thus, to Some
`extent, the temperature Sensor temperature detected by the
`temperature sensor silicon diode 116 is effected by the
`temperature of the CPU core 104. However, blowing air
`across the CPU 102 generally has less of a cooling effect on
`the CPU core 104 than throttling down the CPU core. That
`is, cooling the external regions of the CPU 102 may keep the
`external CPU area cool, but does not cool the Source of the
`heat generation, the CPU core 104. This means that a CPU
`core 104 that has become excessively warm or hot is best
`cooled by throttling down the CPU core. Blowing air across
`the CPU 102 has some, but less, effect on cooling a CPU
`core 104.
`25
`On the other hand, the exterior region 109 of the CPU 102
`may become excessively warm from heat generated by
`another device in the computer System. Although not shown
`in FIG. 1, an interface card Such as a peripheral component
`interconnect (“PCI”) card or PCMCIA card may become hot
`from use and its heat radiates to the CPU 102, which in turn
`becomes warm. In this situation, the temperature Sensor
`temperature of the exterior region 109 of the CPU 102 may
`increase, but not the CPU die 105 temperature. This situation
`can best be corrected by blowing a sufficient volume of air
`across the CPU 102. Throttling down the CPU core 104 has
`less of an effect in cooling a CPU 102 that has become
`excessively warm from a separate device in the computer
`System.
`Thus, in accordance with the preferred embodiment,
`thermal control logic 108 monitors both the CPU die tem
`perature Via Silicon diode 114 and the temperature Sensor
`temperature via Silicon diode 116 and independently adjusts
`the CPU core 104 throttling and fan speed depending on the
`which temperature has become excessive. If the CPU die
`temperature becomes excessively warm, the thermal control
`logic 108 responds by throttling down the CPU core 104,
`while preferably not adjusting the speed of fan 180. As the
`CPU die temperature then decreases below a threshold as a
`result of a slower clock signal, the thermal control logic 108
`can throttle up the CPU core to increase performance of the
`computer System. If, however, the temperature Sensor tem
`perature becomes excessively warm, the thermal control
`logic 108 preferably responds by increasing fan Speed, while
`preferably not adjusting the throttling of the CPU core 104.
`Once the temperature Sensor temperature reduces below a
`threshold as a result of increased air flow over the CPU 102,
`the thermal control logic 108 preferably reduces the fan
`Speed.
`By independently controlling CPU throttling and fan
`Speed, adjustments to fan Speed are not effected much by
`relatively rapid fluctuations in CPU die temperature.
`Accordingly, the annoyance of a fan that rapidly turns on
`and off and adjusts its Speed is lessened.
`Numerous embodiments exist to implement the thermal
`control logic 108 of FIG. 1. Referring now to FIG. 2, one
`exemplary embodiment of computer system 100 includes a
`
`50
`
`8
`CPU 102, bus bridge devices 120 and 130, main memory
`124, a keyboard controller 140, a power supply 160, and a
`fan 180. As shown, computer system 100 also includes a
`graphics controller 123, a display 125, a BasicInput/Output
`System Only Memory (“BIOS ROM'), a keyboard 172, and
`a fan controller 188. One of ordinary skill in the art will
`recognize that computer System 100 may include other
`components Such as disk drives, a pointing device, etc.
`In accordance with the preferred embodiment of FIG. 2,
`the thermal control logic 108 of FIG. 1 is implemented using
`as much hardware as possible that already is present in the
`computer System. For example, Some of the functions per
`formed by the thermal control logic 108 are performed by
`keyboard controller 140 as described below. If desired,
`however, additional hardware can be added to the computer
`system diagram of FIG. 2 specifically to provide t