US Patent 7761274 Temperature-based clock frequency controller apparatus and method

A temperature-based clock frequency controller is implemented in an integrated circuit such as a microprocessor. The temperature-based clock frequency controller includes a register to store a threshold temperature value, a thermal sensor, and clock adjustment logic to decrease a clock frequency in response to the thermal sensor indicating that the threshold temperature value has been exceeded. In a microprocessor implementation, the microprocessor contains a plurality of thermal sensors each placed in one of a plurality of different locations across the integrated circuit and an averaging mechanism to calculate an average temperature from the plurality of thermal sensors. Threshold adjustment logic increases the threshold temperature value to a new threshold temperature value in response to the thermal sensor indicating that the threshold temperature value has been exceeded. Threshold adjustment logic further lowers the new threshold temperature to detect decreases in temperature. In addition, the microprocessor contains halt logic that halts operation of the microprocessor when the temperature attains a critical temperature.