Method and apparatus for thermal sensitivity based dynamic power control

Abstract

A method and system provides dynamic power control based on thermal sensitivity of a processor system. The method and system includes a circuit that reduces the clock frequency for the processor system in response to thermal characteristics satisfying a pre-determined threshold that allows maximal thermal temperature limit utilization without substantially degrading processor performance.

What is claimed is:  
     
         1 . An apparatus for dynamic power control of a processor based on a thermal condition, comprising: 
 a sensor to measure a thermal characteristic of a processor with a clock frequency;    a circuit, responsive to the measured thermal characteristic satisfying a pre-determined threshold, to reduce the clock frequency of the processor.    
     
     
         2 . The apparatus of  claim 1 , wherein the thermal characteristic includes temperature and rate of temperature change.  
     
     
         3 . The apparatus of  claim 1 , wherein the circuit includes a frequency generator and a logic circuit.  
     
     
         4 . The apparatus of  claim 1 , wherein the circuit reduces the clock frequency by less than fifty percent.  
     
     
         5 . The apparatus of  claim 1 , wherein the circuit reduces the clock frequency by removing a pre-determined number of transitions from a signal producing the clock frequency.  
     
     
         6 . The apparatus of  claim 1 , wherein the sensor and circuit produce a higher operating temperature for the processor.  
     
     
         7 . A method for dynamic power control of a processor based on a thermal condition, comprising: 
 measuring a thermal characteristic of a processor with a clock frequency;    reducing the clock frequency in response to the measured thermal characteristic satisfying a pre-determined threshold.    
     
     
         8 . The method of  claim 7 , wherein the step of measuring includes measuring temperature and rate of temperature change.  
     
     
         9 . The method of  claim 7 , wherein the step of reducing includes reducing the clock frequency by less than fifty percent.  
     
     
         10 . The method of  claim 7 , wherein the step of reducing includes reducing the clock frequency by removing a pre-determined number of transitions from a signal producing the clock frequency.  
     
     
         11 . The method of  claim 10 , wherein the step of reducing includes reducing the clock frequency in response to the measured thermal characteristic satisfying a pre-determined threshold to produce a higher operating temperature of the processor.  
     
     
         12 . A method for using control logic to provide dynamic power control of a processor based on a thermal condition, comprising: 
 entering a first state from a second state in response to a measured thermal characteristic of a processor with a clock frequency failing to satisfy a first pre-determined threshold where the first state outputs the clock frequency for the processor and the second state reduces the clock frequency for the processor;    remaining in the first state in response to a measured thermal characteristic of the processor failing to satisfy the first pre-determined threshold; and    entering the second state from the first state in response to a measured thermal characteristic of the processor satisfying the first pre-determined threshold.    
     
     
         13 . The method of  claim 12 , wherein the thermal characteristic of the processor includes temperature and rate of temperature change.  
     
     
         14 . The method of  claim 12 , further comprising: 
 entering a third state from the first state in response to a measured thermal characteristic of the processor satisfying a second pre-determined threshold where the third state waits for a measured thermal characteristic of the processor to satisfy a third pre-determined threshold to reduce the clock frequency for the processor;    remaining in the third state in response to a measured thermal characteristic of the processor failing to satisfy the third pre-determined threshold; and    entering the first state from the third state in response to a measured thermal characteristic failing to satisfy the second pre-determined threshold.    
     
     
         15 . The method of  claim 14 , wherein the second pre-determined threshold is a temperature threshold, and the third pre-determined threshold is a rate of temperature change threshold.  
     
     
         16 . The method of  claim 14 , further comprising: 
 entering the second state from the third state in response to a measured thermal characteristic of the processor satisfying the third pre-determined threshold;    remaining in the second state in response to a measured thermal characteristic of the processor satisfying the third pre-determined threshold; and    entering the third state from the second state in response to a measured thermal characteristic of the processor failing to satisfy the second pre-determined threshold.    
     
     
         17 . The method of  claim 16 , wherein the second pre-determined threshold is a temperature threshold, and the third pre-determined threshold is a rate of temperature change threshold.