Patent ID: 8358729

Claim:
A method comprising: receiving a first phase correction signal representing a phase difference between a source signal and a reference signal; generating a first control voltage from the first phase correction signal using a charge pump circuit; generating a third control voltage, the combination of the first control voltage and the third control voltage including an offset error component due to time interval imbalances of the third control voltage; generating a second control voltage from the first phase correction signal in response to a digitally filtered version of the phase correction signal, wherein the second control voltage corrects for the offset error by balancing the time interval imbalances, wherein the first control voltage is generated in parallel with the second control voltage from the first phase correction signal; calculating a VCO control signal based on a linear combination of the first control voltage, the third control voltage, and the second control voltage by summing the first control voltage, the third control voltage, and the second control voltage; and generating the source signal in response to the VCO control signal.