Patent ID: 7276977

Claim:
A timing loop circuit comprising first and second phase detectors, wherein during a first time period, the first phase detector is coupled in a closed timing loop and the second phase detector is decoupled from the closed timing loop and calibrated, and during a second time period, the second phase detector is coupled in a closed timing loop and the first phase detector is decoupled from the closed timing loop and calibrated and wherein the first phase detector includes a first input, a second input, an adjust input, and an output; the second phase detector includes a first input, a second input, an adjust input, and an output; the circuit further comprising a voltage controlled oscillator having an input coupled to the output of the first phase detector and the output of the second phase detector, and an output coupled to the second input of the first phase detector and the second input of the second phase detector; and a mismatch detector having one or more inputs coupled to the output of the first phase detector and the output of the second phase detector, and one or more outputs coupled to the adjust input of the first phase detector and the adjust input of the second phase detector, wherein during the first time period, the output of the first phase detector is coupled to the voltage controlled oscillator, the first and second inputs of the second phase detector are coupled to a common input signal, and the output of the second phase detector is coupled to the mismatch detector, and in accordance therewith, the mismatch detector generates a correction signal for adjusting the second chase detector, and during a second time period, the output of the second phase detector is coupled to the voltage controlled oscillator, the first and second inputs of the first phase detector are coupled to a common input signal, and the output of the first phase detector is coupled to the mismatch detector, and in accordance therewith, the mismatch detector generates a correction signal for adjusting the first phase detector.