Patent ID: 7202750

Claim:
A phase locked loop comprises: a difference detection module operably coupled to determine a difference signal based on at least one of a phase difference and a frequency difference between a reference oscillation and a feedback oscillation; a loop filter module operably coupled to convert the difference signal into a control signal; a ring oscillator having a plurality of delay stages and a plurality of taps coupled to a corresponding plurality of outputs of the plurality of delay stages, the ring oscillator for producing an output oscillation based the control signal; an output oscillation adjust module operably coupled to the ring oscillator for producing an effective output oscillation based on an oscillation control signal, wherein the output oscillation adjust module includes an output select block, operably coupled to the plurality of taps, for producing the effective output oscillation from a sequence of selected taps from the plurality of taps, and a tap adjust control generator, responsive to the oscillation control signal for generating a sequence of tap adjust control signals that command the output select block to select the sequence of selected taps from the plurality of taps; a divider module operably coupled to convert the effective output oscillation into a divided oscillation; and a delay adjust module operably coupled to the divider module for producing the feedback oscillation by adjusting the divided oscillation, wherein the delay adjust module includes a variable delay control generator for generating a variable delay control signal and a variable delay adjustment module for adjusting the divided oscillation.