According to an example embodiment, an apparatus for controlling a power supply voltage for an integrated circuit may be provided, which may include a plurality of different types of process region detection circuits, each process region detection circuit configured to identify a respective process region of a plurality of process regions. The apparatus may also include a voltage selection circuit configured to determine a highest voltage among the voltages associated with the identified process regions and to select a power supply voltage for the integrated circuit that is equal to the highest voltage, one or more functional test circuits configured to perform a functional test using the selected power supply voltage, and a voltage adjuster circuit configured to increase the selected power supply voltage if the functional test fails.