Patent ID: 7355429

Claim:
Apparatus for monitoring a power supply line in an integrated circuit, comprising: sensor circuitry, the sensor circuitry preconditioning a first signal and a second signal, 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 operation comprising shifting respective levels of the voltages such that the voltages are within an input voltage range of comparator circuitry; and comparator circuitry coupled to the sensor circuitry, the comparator circuitry comparing the preconditioned first signal and the preconditioned second signal, the comparing operation 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 comprise a first sensor for preconditioning the first signal and a second sensor for preconditioning the second signal; 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.