On-die power sensor for performing run-time power/voltage/current management

A method of performing on-die run-time power/voltage/current management, comprising:

• selectively coupling a first ring oscillator in a digital current sensor to a first power voltage or a second power voltage in a processor;
• selectively coupling a second ring oscillator in the digital current sensor to the first power voltage or the second power voltage in the processor, wherein the first ring oscillator and the second ring oscillator are identical in structure;
• measuring speed counts of the first ring oscillator and the second ring oscillator and acquiring an overall delta speed count between the first ring oscillator and the second ring oscillator using the digital current sensor;
• converting the overall delta speed count between the first ring oscillator and the second ring oscillator to a voltage drop based on a trimmed slope of a first lookup table associated with a relationship between a speed count and an applied voltage of each ring oscillator using the digital current sensor;
• converting the voltage drop to a run-time current based on a trimmed direct current resistance (DCR) of a second lookup table associated with a relationship between a DCR and the applied voltage of each ring oscillator using the digital current sensor;
• recording values of the speed counts measured by the digital current sensor to quantify a run-time voltage based on a third lookup table associated with a relationship between the speed count and a step voltage of each ring oscillator using a digital voltage sensor;
• and
• obtaining a run-time power by multiplying the run-time current and the run-time voltage.