| 摘要 |
A power-up signal generating circuit is provided to generate a stable power-up signal during an initial operation, by shifting the level of an internal power supply voltage and generating a power-up signal when an external power supply voltage and the shifted internal power supply voltage are stable. A level shifter generates an internal voltage signal having an external power supply voltage level by level-shifting an internal power supply voltage. A power-up generation part(20) detects the level of the external power supply voltage, and enables a power-up signal when the potential of the external power supply voltage is above a constant potential and the internal voltage signal is enabled. In the power-up generation part: a voltage sensing part(21) senses that the potential of the external power supply voltage becomes above the constant potential; a level control part(22) supplies the external power supply voltage according to an output voltage of the voltage sensing part; a power-up signal generation part(23) enables a detection signal when the output voltage level of the level control part is above a constant voltage; and a buffering part(24) buffers and enables the power up signal when the detection signal and the internal power supply voltage signal are enabled.
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