An apparatus for detecting a change in a voltage level of a power supply is disclosed. An inverter coupled to a first power supply may generate a signal dependent upon a voltage level of a second power supply. A latch coupled to the first power supply may be set based on a first voltage level of the second power supply and a first value of the signal, and re-set based on a second voltage level of the second power supply and a second value of the signal different than the first value of the signal.