INTEGRATED CIRCUIT DEVICES HAVING ENHANCED CLOCK GENERATORS THEREIN

A clock generator includes a phase controller configured to generate phase control information in response to comparing a phase of an input clock signal against a phase of a division clock signal, and an oscillator configured to generate a plurality of oscillation signals at an equivalent output frequency but different phases, in response to the phase control information and duty control information. A duty cycle converter is provided, which is configured to generate a plurality of output clock signals at the output frequency by adjusting duty cycles of the plurality of oscillation signals, such that the plurality of output clock signals have duty cycles smaller than the duty cycles of the plurality of oscillation signals. A clock divider is provided, which is configured to generate the division clock signal by dividing the output frequency of one of the plurality of output clock signals, such that the division clock signal has a division frequency smaller than the output frequency. A duty cycle calibrator is provided, which is configured to generate the duty control information for adjusting a duty cycle difference of the plurality of output clock signals, in response to detecting duty cycle differences between the plurality of output clock signals.