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US 5,422,806 AGranted
Temperature control for a variable frequency CPU
AssigneeACC Microelectronics Corporation
InventorsPeng-Cheng Chen, Terng-Huei Lai
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AssigneeACC Microelectronics Corporation
InventorsPeng-Cheng Chen, Terng-Huei Lai
Estimating the term…
A thermal control system for variable speed microprocessor with a piecewise estimate of temperature change. The estimate is modeled after actual temperature change measurements of a microprocessor operating at low and high speeds and is recorded in a digital format in storage registers, one set of registers for each operating frequency. A counter counts sample microprocessor clock signals for a time over which the microprocessor speed is operating at a specific speed and provides a basic count signal. This basic count signal is incremented or decremented by comparison with stored values of the piecewise estimate of temperature change. As the basic signal increases or decreases, new slopes are provided to the counter for adjusting the basic count, upwards or downwards, depending on whether the system speed is high, intermediate or low. The adjusted counter output is also fed to comparators, which monitor a desired upper and lower temperature limit. As the upper limit is approached, control logic implements a throttling algorithm to maintain temperature in the desired range. The present invention takes into account the operating history of the system in a particular environment since the system powers on, including idleness of the system.
A method of temperature control for a CPU whose frequency is variable and whose temperature change characteristics over time are a non-linear function of clock rate comprising,
The method of claim i wherein the correlating of the measurements of elapsed time and frequency with the piecewise estimate of CPU temperature change is done by computing points and slopes defining piecewise segments of said estimate of CPU temperature change as a function of time and then generating a count signal based on the measurements of CPU operating frequency and elapsed time, the count signal being incremented or decremented based upon the magnitude and direction of the applicable piecewise segment.
An apparatus for temperature control of a CPU whose frequency is variable and whose temperature change characteristics over time are a non-linear function of clock rate comprising,
Dependencies are inferred from the claim text.