Electrical computers and digital processing systems: support – Computer power control – Having power source monitoring
Reexamination Certificate
1998-06-30
2001-09-04
Dharia, Rupal (Department: 2181)
Electrical computers and digital processing systems: support
Computer power control
Having power source monitoring
C320S106000, C320S128000, C320S132000, C320S143000, C320S150000
Reexamination Certificate
active
06286109
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and apparatus for reducing heat generation in a portable computer.
BACKGROUND OF THE INVENTION
Portable electronic devices, such as notebook computers, typically generate relatively large amounts of heat during normal operation. To prevent malfunctioning of these devices due to thermal overload, it is typically necessary to control the temperature at critical locations in the devices. In desktop computers, the problem of thermal control is more easily solved through the use of fans, cooling slots in the chassis, and relatively large heat sinks.
In battery-powered portable computers, it is undesirable to use fans because of their power consumption, acoustic and electrical noise, and physical size, and because of space limitations, it is undesirable to use cooling slots and large heat sinks. Typical portable computers therefore achieve thermal control through the careful layout of components, and by controlling power consumption. One of the primary ways in which power consumption is controlled is by reducing the frequency of clock signals within the central processing unit (CPU) of the portable computer. A 50% reduction in the frequency of the clock signals will typically reduce the CPU power consumption and heat generation by approximately 50%.
SUMMARY OF THE INVENTION
In one general aspect, the invention features a computer including a battery having a first terminal, a battery charging circuit having an output operatively connected to the first terminal of the battery and having a control input, and a temperature sensor responsive to temperature at a location within the computer and having a temperature indicating output operatively connected to the control input of the battery charging circuit.
The battery charging circuit can be responsive to a control value of the control signal to set a charging rate of the battery. The temperature sensor can be responsive to the temperature of computing circuitry within the computer. The battery charging circuit can be constructed and arranged to reduce a charging rate of the charging circuit when a temperature detected by the temperature sensor exceeds a reference value. A factor by which the charging rate is reduced can be based upon a magnitude of a difference between the temperature detected and the reference value. The battery charging circuit can reduce the charging rate by reducing a magnitude of charge current supplied to the battery. A pulse width of pulses contained within a control signal of the charging circuit can be used to determine the control value.
In another general aspect, the invention features a method for controlling heat dissipation within a portable electronic device having a battery and a battery charging circuit. The method includes steps of charging the battery at a charging rate, detecting a temperature of electronic components within the portable electronic device, determining whether the temperature exceeds a reference value, and reducing the charging rate when the temperature exceeds the reference value.
The determining step can include a step of determining a magnitude of a difference between the temperature detected and the reference value, and the step of reducing can include a step of reducing the charge rate by a factor based upon the magnitude of the difference between the temperature detected and the reference value. The step of reducing the charge rate can include a step of reducing a magnitude of a charge current from the charging circuit to the battery. The step of detecting can include a step of detecting a plurality of temperatures at a plurality of locations in the portable electronic device, and the step of determining can include a step of determining whether any of the plurality of temperatures exceeds a corresponding reference value. The method can further include a step of reducing a clock rate to components of the computer in response to a determination that the temperature exceeds a second reference value.
In another general aspect, the invention features a computer including a battery, means for charging the battery, means for detecting a temperature of at least one location within the computer, and means for reducing a charging rate of the means for charging when the temperature exceeds a reference value.
The means for reducing the charging rate can include means for reducing a magnitude of a charge current from the battery charger to the battery. The temperature detection circuit can be adapted to detect a plurality of temperatures at a plurality of locations in the computer, and wherein the means for reducing power consumption can include means for reducing power consumption when any of the plurality of temperatures exceeds a corresponding reference value.
Systems according to the invention may be advantageous in that they can permit more versatile temperature control of a personal computer. This may allow the computer to operate at a lower temperature, or within a more consistent temperature range. As a result, the mean time between failure of the components of the computer can be increased.
Systems according to the invention may also be advantageous in that they permit temperature control without reducing the computational performance of the computer. This can provide more computational power to the user, even in high temperature environments.
REFERENCES:
patent: 5557188 (1996-09-01), Piercey
patent: 5583417 (1996-12-01), Yuen
patent: 5592070 (1997-01-01), Mino
patent: 5777399 (1998-07-01), Shibuya
patent: 5900717 (1999-05-01), Lee
Dharia Rupal
Digital Equipment Corporation
Fletcher Yoder & Van Someren
LandOfFree
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