Abstract: Disclosed is a power-up detection circuit of a semiconductor device which generates an output signal enabling an activation of the semiconductor device to be maintained only when an internal power voltage is more than a predetermined voltage level. In the power-up detection circuit, a level detection section is provided for detecting a level of the internal power voltage to generate a first level detection signal when the internal power voltage is less than the predetermined voltage level and to generate a second level detection signal when the internal power voltage is not less than the predetermined voltage level. And, an output driver is provided for enabling the internal circuits to be at inactive state in response to the first level detection signal, and generating the output signal having the same waveform as the internal power voltage in response to the second level detection signal.