PHASE LOCKED LOOP CIRCUIT CAPABLE OF PREVENTING OSCILLATION FREQUENCY MALFUNCTION DUE TO LEAKAGE CURRENT GENERATED FROM A LOOP FILTER AND A SYSTEM INCLUDING THE SAME

摘要

PURPOSE: A phase locked loop circuit and a system including the same are provided to compensate a level change of frequency control voltage due to leakage current, thereby preventing the level change of the frequency control voltage.;CONSTITUTION: A voltage control part(10) controls a voltage level of frequency control voltage according to a phase difference between a reference clock and oscillation clock. A loop filter(12) is generally corresponding to a low pass filter. A voltage control oscillator(13) outputs the oscillation clock with a frequency corresponding to the voltage level of the frequency control voltage. A divider(14) generates a division clock with a low frequency by dividing the oscillation clock with a high frequency. A current control circuit(15) compensates a level change of the frequency control voltage due to a leakage current by generating a compensation current corresponding to the leakage current generated from the loop filter.;COPYRIGHT KIPO 2012