Patent ID: 7633824

Claim:
A voltage generating circuit in which a plurality of charge pumps are arranged between an input and an output, comprising: a first charge pump unit to which a first clock signal having a first voltage level is inputted, the first charge pump unit generating a first precharge pumping voltage by pumping a voltage of a first external power supply in stages by a first voltage; a voltage selector that is coupled to any one of the first power supply and a second external power supply having a higher voltage value than the first external power supply, the voltage selector selecting from the first precharge pumping voltage generated by the first charge pump unit or the voltage of the second external power supply, in accordance with a voltage selection command signal; a level converter that converts a voltage level of the first clock signal into a second voltage level that is higher than the first voltage level; and a second charge pump unit to which a second clock signal having the second voltage level is inputted, the second charge pump unit generating a second precharge pumping voltage by pumping the first precharge pumping voltage or the voltage of the second external power supply selected by the voltage selector in stages by a second voltage with a greater potential difference than the first voltage.