ASYMMETRY CHARGE PUMP AND A PHASE LOCKED LOOP INCLUDING THE SAME, CAPABLE OF REDUCING A LOCK SKEW BY COMPARING A CHARGING CHARGE AND A DISCHARGING CHARGE

摘要

PURPOSE: An asymmetry charge pump and a phase locked loop including the same are provided to reduce a lock screw by including an asymmetry charge pump to control the time when the current is inputted to the loop filter and the current is outputted from the loop filter.;CONSTITUTION: A current source(121,122) generates a current inputted from the outside or current outputted to the outside through an output node. A switching circuit is connected between an output node(N2) and a current source. The switching circuit switches according to the phase difference of a reference signal and the feedback signal. The switching circuit compares the charge charged to the outside and the charge discharged from the outside. A switching circuit(123) reduces a lock screw by controlling the time when the current is outputted or inputted according to the comparison result.;COPYRIGHT KIPO 2011