ASYMMETRIC CHARGE PUMP AND PHASE LOCKED LOOPS HAVING ITS

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.