Patent ID: 7233163

Claim:
A method comprising: providing an integrated circuit (IC) having a plurality of oscillators at distributed locations in the IC, the IC being a microprocessor; determining a respective rate of oscillation of each of the oscillators; detecting variations in local power supply voltage in the IC based on the determined rates of oscillation; running an application program on the IC; and after running the application program, placing the IC in a condition in which no program is running on the IC; and wherein: the determining is performed both with the application program running and with the IC in the condition in which no program is running; and the detecting of the local variations in power supply voltage includes: detecting a respective local temperature at each of the oscillators based on the respective rate of oscillation of each the oscillators with the IC in the condition in which no program is running; and calculating a respective local power supply voltage at each of the oscillators based on the detected respective local temperature at each of the oscillators and based on the respective rate of oscillation of each of the oscillators with the application program running on the IC.