An integrated circuit (103) having a plurality of integrated circuit portions (111, 113, and 115) where each of the plurality of integrated circuit portions receives a corresponding voltage of a plurality of voltages. Selection circuitry (127 and 123) selects a selected voltage of the plurality of voltages and provides an indication of the selected voltage to adjust the supply voltage to the integrated circuit. in one embodiment, the indication may correspond to an analog signal proportional to the selected voltage such as e.g. at the selected voltage or at a voltage less than or greater than the selected voltage. A power supply system (105), coupled to the integrated circuit, may be used to receive the indication of the selected voltage and adjust the supply voltage based on the indication.