Patent ID: 7136441

Claim:
A clock recovery unit for recovering a clock synchronized with a given data signal, the clock recovery unit comprising: a voltage controlled oscillator for generating a clock having a frequency according to a control voltage; a first charge pump and a second charge pump whose respective outputs are coupled to a common node; a first phase detector for detecting a phase error in the clock with respect to one of a rising edge and a falling edge of the data signal so as to control the first charge pump according to the phase error; a second phase detector for detecting a phase error in the clock with respect to the other one of the rising edge and the falling edge of the data signal so as to control the second charge pump according to the phase error detected by the second phase detector; and means for controlling a transition characteristic of the data signal according to an output of one of the first and second phase detectors, wherein a voltage that is generated at the common node by the first and second charge pumps is given to the voltage controlled oscillator as the control voltage so that the phase error detected by the first phase detector and the phase error detected by the second phase detector are both reduced.