Apparatus and method of controlling and tuning a fine calibration for clock source synchronization in dual loop of hybrid phase and time domain

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. The phase detector connected to the first fine calibration unit is used to detect a phase difference between the reference and the feedback signals and outputting an indicating signal corresponding to the phase difference between the reference and the feedback signals. The controller controls the coarse calibration unit and the first fine calibration unit to align the feedback signal to the reference signal according to the indicating signal generated from the phase detector. The rotating detector rapidly tunes the phase difference between the feedback signal and the reference signal by adding a number of time delays to the feedback signal when the feedback signal and the reference signal are miss-aligned.