Phase lock loop, has phase comparator controlling charge pump based on phase difference of signals received from frequency dividers and current source removing/injecting current in pump output to create phase-shift between signals` fronts

摘要

The loop has a charge pump (22) supplying a voltage controlled oscillator. A phase comparator (26) receives signals from frequency dividers (30, 32) dividing a reference frequency and a frequency of an oscillator output signal, respectively to control the pump based on phase difference of the signals. A current source (36) removes or injects current in the output of the pump to create a phase-shift between active fronts of the signals. An independent claim is also included for a method of controlling a voltage controlled oscillator of a phase lock loop.