Patent ID: 7190211

Claim:
A semiconductor device equipped with a step-up circuit, said voltage step-up circuit comprising: multiple charge pump units connected in series, each unit including a MOS transistor and a capacitor having one end connected to the input or output end of said MOS transistor and another end connected to a clock line supplying a clock, said charge pump circuit adapted to step up a supply voltage in response to said clock; and a clock generation circuit for generating said clock in response to a startup signal, wherein said clock generation circuit generates and provides to said capacitors a limited current supply clock having a limited current supply capability until a predetermined condition is satisfied after the reception of said startup signal, wherein said predetermined condition is that a predetermined period of time has elapsed after the reception of said startup signal, wherein said clock generation circuit includes a timer for initiating a startup time control signal a predetermined time after the reception of said startup signal; a controllable buffer adapted to be synchronized to an external clock in response to said startup signal, said buffer adapted to output said limited current supply clock as limited by said startup control signal.