PLL PHASE/FREQUENCY DETECTOR WITH FULLY DIFFERENTIAL OUTPUT CHARGE PUMP

摘要

PROBLEM TO BE SOLVED: To provide a method for equalizing charge currents of a phase locked loop. SOLUTION: Charge currents in a charge pump of a phase locked loop are equalized by controlling one of DC current sources by using a feedback signal generated from a common mode voltage of a fully differential phase locked loop filter. The feedback signal is generated by a detector/filter for detecting the common mode voltage of the fully differential phase locked loop filter and for low-pass-filtering the common mode voltage in order to remove a differential signal component. COPYRIGHT: (C)2005,JPO&NCIPI