An integrated circuit that supports both internal and external voltage regulators as well as various modes, such as a low power mode or a test mode, includes voltage regulator selection circuitry and power control circuitry. The regulator selection circuitry selects one of internal and external regulators based on two pin conditions. The power control circuitry controls ON/OFF status of the regulators corresponding to a power mode, including power-on reset, entering a low power mode, and wake-up from a low power mode.