Patent ID: 7443187

Claim:
A method of monitoring a power supply line in an integrated circuit, comprising the steps of: preconditioning a first signal and a second signal in accordance with sensor circuitry, the first signal being representative of a voltage of the power supply line being monitored, the second signal being representative of a voltage of a reference power supply line, the preconditioning step comprising shifting respective levels of the voltages such that the voltages are within an input voltage range of comparator circuitry; and comparing the preconditioned first signal and the preconditioned second signal in accordance with the comparator circuitry, the comparing step detecting when a difference exists between the voltage level of the preconditioned first signal and the voltage level of the preconditioned second signal; wherein the sensor circuitry comprises a pair of matched sensors, wherein the pair of matched sensors comprises a first sensor for the step of preconditioning the first signal and a second sensor for the step of preconditioning the second signal, further wherein the first sensor is configured such that the preconditioned first signal output by the first sensor is responsive to a fluctuation in the voltage of the power supply line being monitored.