Thermal model for central processing unit

摘要

A technique for implementing a programmable thermal model of an integrated circuit component such as a central processing unit (CPU) and its associated heat sink. The model estimates the die temperature of the component as if there were no cooling devices present in the system such as a forced air cooling fan by integrating the thermal energy added when the component is active and by integrating the thermal energy removed when it is idle. A programmable power value may be used to represent the heat added to the model at each model sample period. The effect of a heat sink in cooling the idle component may be modeled by reducing the value of the heat accumulator by a predetermined fractional amount during each sample period. The decay time constant for the model may be changed by then adjusting the sample period. With an accurate model estimate predicting the component temperature in the absence of cooling being instantaneously available, any associated cooling device such as a fan can be operated in such a manner as to turn on only when it is estimated to actually be needed and to be kept off at all other times. In addition, a turn off delay can be implemented in order to avoid undesirable cycling effects.