A voltage converter, including a switch circuit configured to generate an output voltage by switching an input voltage and a ground voltage based on a driving control signal; an error voltage generator configured to generate an error voltage based on a comparison between the output voltage and a reference voltage; a duty signal generator configured to generate a duty signal having a constant pulse frequency or a modulated pulse frequency, based on a result of the comparing; and a driving controller configured to generate the driving control signal based on the duty signal.