Patent ID: 8368385

Claim:
A system, comprising: an integrated circuit including a voltage grid to provide a voltage to circuitry within the integrated circuit; a sensor circuit within the integrated circuit, adjacent and coupled to a node of the voltage grid, including a ring oscillator to generate a pulse stream in response to the voltage at the node and to adjust a frequency of the pulse stream in response to changes in the voltage at the node, and an asynchronous counter to count pulses of the pulse stream; monitor and control circuitry within the integrated circuit to enable the sensor circuit and to evaluate the count, including: count averaging circuitry to average the counts over time an average threshold generator to generate a variable threshold as a sum of a the average count and an offset value; and circuitry to evaluate the counts with respect to the variable threshold; and a plurality of additional sensor circuits within the integrated circuit, each adjacent and coupled to corresponding additional nodes, each including a corresponding ring oscillator and asynchronous counter, wherein at least a portion of the monitor and control circuitry is shared amongst the sensor circuits.