A voltage controller may include a pulse generator and an internal voltage control circuit coupled to the pulse generator. The pulse generator may be configured to generate a control signal in response to at least one of a mode signal and/or an external voltage. The internal voltage control circuit may be configured to generate an internal voltage at an internal voltage node, and the internal voltage control circuit may include a voltage divider, first and second comparators, and a driver. The voltage divider may be coupled between the internal voltage node and a first reference voltage, and the voltage divider may generate a feedback voltage that is between the internal voltage and the first reference voltage. The first comparator may be configured to generate a first comparison result responsive to comparing the feedback voltage with a second reference voltage, and the second comparator may be configured to generate a second comparison result responsive to comparing the feedback voltage with the second reference voltage in response to the control signal. The driver may be coupled between an external voltage and the internal voltage node, and the driver may be configured to generate the internal voltage responsive to the first and second comparison results. Related methods and smart cards are also discussed.