Patent ID: 7764561

Claim:
A self-refresh period measurement circuit of a semiconductor device comprising: delay means for receiving an oscillation signal that is periodically enabled after a self-refresh signal is enabled, to allow a self-refresh operation to be performed, delaying the received oscillation signal by a unit self-refresh period to output a first delayed oscillation signal, by a predetermined integer multiple of the unit self-refresh period to output a second delayed oscillation signal, and delaying the received oscillation signal by the predetermined integer multiple of the unit self-refresh period plus the unit self-refresh period to output a third delayed oscillation signal; a first period measurement start signal generator for receiving the self-refresh signal and the oscillation signal and generating a first period measurement start signal for setting a time that the oscillation signal is enabled for the first time as a start time for measurement of a self-refresh period; and a first refresh period output unit for receiving the first period measurement start signal and the first delayed oscillation signal, and generating a first refresh period output signal that is enabled for a period from a time that the first period measurement start signal is enabled to a time that the first delayed oscillation signal is enabled for the first time.