A voltage supply circuit includes a voltage generator and a controller. The voltage generator is configured to pump an externally input voltage and store the pumped external voltage as a first voltage having a set voltage level, before power-up begins, or pump the external voltage, add the pumped voltage to the stored voltage, and output the added voltage as an operating voltage. The controller is configured to output a first control signal to drive the voltage generator or stop operation of the voltage generator, according to an operating state.