US Patent 7671649 Apparatus and method for generating multi-phase clocks

An apparatus for generating multi-phase clocks in accordance with the present invention includes a clock delay configured to delay a source clock by a delay time corresponding to a control signal to generate a plurality of clocks; a clock multiplexer configured to output a first clock for a first locking region and a second clock for a second locking region sequentially as a selected clock in response to a locking detection signal; a phase detector configured to detect a phase of the selected clock in comparison to a phase of the source clock to output a phase detection signal; and a control voltage signal generator configured to generate the control signal corresponding to the phase detection signal.