Abstract: A power-up circuit includes a power-up signal generating section connected to an external source terminal, configured to generate a power-up signal when the external source reaches a predetermined target level, and to selectively interrupt a path from the external source terminal in response to a selection signal. A pulse generating section generates a pulse with a predetermined pulse width to control an initializing operation with reference to an activation time of the power-up signal. A power-up controlling section provides the power-up signal generating section with the selection signal, variable by the pulse, when the power-up signal is active.