All digital phase locked loop and method of controlling the same

摘要

There are provided an all digital phase locked loop and a method of controlling the same. The all digital phase locked loop includes a phase comparator comparing phases of a target signal having a reference frequency and a digital oscillation feedback signal having a feedback frequency; a virtual value controller controlling a preset initial virtual value according to a phase comparison result from the phase comparator to generate an adjusted virtual value when the reference frequency is a frequency included between two preset lower and higher digital codes; a random number generator generating a random number within a range of a plurality of virtual values; a comparator generating digital codes; and a digitally controlled oscillator generating an oscillation signal according to the digital codes from the comparator.