Digital PLL Phase Alignment for Faster Lock and Re-Lock

The patent applies preliminary action by performing phase alignment and calibration operations before the PLL loop is closed. The system pre-determines phase alignment coefficients and adjusts the frequency divider settings in advance, so that when the loop closes, the phase error is already minimized. This preliminary preparation eliminates the need for long convergence periods and prevents synchronization issues, directly resolving the contradiction between fast convergence and accurate synchronization.

The patent implements feedback mechanisms by using a time-to-digital converter to measure phase errors between reference and feedback clock signals. The measured phase error is fed back through a phase alignment circuit that adjusts the frequency divider based on predetermined coefficients. This closed-loop feedback system continuously monitors and corrects phase deviations, ensuring both fast convergence and high synchronization accuracy without the trade-off present in conventional designs.

The patent uses preliminary action to perform all necessary phase alignment and frequency divider adjustments before the PLL loop closes. By pre-calculating phase alignment coefficients and configuring the frequency divider in advance, the system achieves fast locking without needing to operate at high reference clock frequencies during the locking process. This allows the use of slower, more power-efficient clock frequencies while still meeting tight lock time requirements.

The system applies self-service through automatic phase alignment and calibration routines that configure the PLL parameters without external intervention. The phase alignment circuit automatically determines the appropriate frequency divider settings and phase correction values based on initial measurements, enabling the system to achieve optimal performance with minimal power consumption without requiring high-frequency operation during the alignment phase.