Simplified Adaptive Voltage Scaling Using Lookup-Table and Analog Temperature Sensor to Improve Performance Prediction Across Temperature

Abstract

A method of adaptive voltage scaling is shown incorporating a lookup table holding manufacturing characterization data in conjunction with one or more precision analog temperature sensors used for correcting for temperature effects.

What is claimed is: 
     
         1 . A method of adaptive voltage scaling comprising the steps of:
 measuring minimum operating voltage at which a logic circuit operates within design limits at a given operating frequency and die temperature;   repeating the voltage measurement at a range of given operating frequencies and temperatures;   creating a lookup table of the measured voltages indexed by temperature;   selecting the required operating frequency and measured die temperature;   adjusting the voltage source to the to the operating voltage obtained from the lookup table.   
     
     
         2 . The method of adaptive voltage scaling of  claim 1 , wherein:
 the voltage measurements and the creation of the lookup table is performed during manufacturing characterization of the die.   
     
     
         3 . The method of adaptive voltage scaling of  claim 1 , wherein:
 the temperature data used to index into the lookup table is obtained from a temperature sensor incorporated in the die.   
     
     
         4 . The method of adaptive voltage scaling of  claim 1 , wherein:
 the operating voltage is periodically adjusted dependant upon changes in the die temperature as measured by the temperature sensor to the voltage value given in the lookup table for the measured temperature and the specified operating frequency.   
     
     
         5 . The method of adaptive voltage scaling of  claim 1 , wherein:
 a predefined hysteresis band is applied to the temperature measurements to avoid “hunting” caused by minor changes and measurement noise.