Abstract: The present invention provides a way of hysteretic switching for efficiently reducing the heavy switching between two adjacent coarse intervals. The present invention disposes a number of fine intervals to cover a range which is larger than the length of one coarse interval. Each coarse interval comprises some extra fine intervals which are exceeded the boundary of the coarse intervals in one side. The heavy switching will be postponed until the extra fine intervals are used up. In the meantime, the fine calibration unit records the number of extra fine interval which be used. An extra-boundary value will be recorded in the fine calibration unit for determining an initial fine interval in another coarse interval if the heavy switching occurs. It should be noted that the extra-boundary value could be a positive or minus value corresponding to which a forward coarse interval or a backward coarse interval the reference signal drifts into.

Abstract: An apparatus and a method of controlling and tuning clock phase alignment with a dual loop of a hybrid phase and time domain for clock source synchronization in electronic devices are described. The coarse calibration unit generates a plurality of output signals, the output signals having a plurality of fixed phase intervals therebetween. At least one of the fixed phase intervals is equal to complete 360 degrees which are divided by the number of the output signals to cover the phase range of complete 360 degrees. The first fine calibration unit connected to the coarse calibration unit delays the output signals generated from the coarse calibration unit by coupling a programmable delay circuit to adjust the phase of a feedback signal toward the phase of a reference signal.

Abstract: An apparatus and a method of controlling and tuning clock phase alignment with a dual loop of a hybrid phase and time domain for clock source synchronization in electronic devices are described. The coarse calibration unit generates a plurality of output signals, the output signals having a plurality of fixed phase intervals therebetween. At least one of the fixed phase intervals is equal to complete 360 degrees which are divided by the number of the output signals to cover the phase range of complete 360 degrees. The first fine calibration unit connected to the coarse calibration unit delays the output signals generated from the coarse calibration unit by coupling a programmable delay circuit to adjust the phase of a feedback signal toward the phase of a reference signal.

Abstract: An apparatus and a method of controlling clock phase alignment with a dual loop of a hybrid phase and time domain for clock source synchronization in electronic devices are described. The coarse calibration unit generates a plurality of output signals, the output signals having a plurality of phase intervals therebetween. A predetermined phase angle is divided by the number of the output signals to generate one of the phase intervals. The first fine calibration unit connected to the coarse calibration unit delays the output signals generated from the coarse calibration unit by coupling a programmable delay circuit to adjust the phase of a feedback signal toward the phase of a reference signal. The phase detector connected to the first fine calibration unit is used to detect a phase difference between the reference and the feedback signal and outputting an indicating signal corresponding to the phase difference between the reference and the feedback signal.