Memory DLL Periodic Update Circuit for Low-Power Timing Stability

The patent implements periodic update actions for the DLL during power-down and self-refresh modes. An update counter is incremented periodically, and when it reaches a predetermined threshold, the DLL is activated for an update operation. This periodic activation ensures the DLL maintains accuracy while minimizing power consumption by keeping it inactive most of the time.

The patent performs preliminary update actions before the DLL completely loses synchronization. By monitoring the duration of power-down modes and triggering updates at predetermined intervals, the system proactively maintains DLL accuracy rather than waiting for malfunction to occur. This preliminary action prevents timing skew accumulation that would otherwise lead to data output errors.

The patent uses the clock enable signal's high interval to perform preliminary DLL update operations before the low refresh interval begins. The update counter accumulates during the high interval, and when the threshold is reached, the DLL is activated to complete the update operation, ensuring timing accuracy is maintained despite the short duration of the high interval.

The patent implements periodic DLL updates synchronized with the self-refresh emulation mode's clock enable signal cycles. By triggering updates at regular intervals during the high intervals and completing them during the transition to low intervals, the system ensures sufficient update time is allocated periodically without extending the overall refresh interval, thus maintaining low power consumption.

The patent implements periodic DLL updates at predetermined intervals rather than continuous updates. The update counter increments with each clock cycle, and the DLL is activated only when the counter reaches a threshold value. This periodic approach ensures the DLL remains functional and synchronized while minimizing the duration the clock enable signal must remain high, thus reducing overall power consumption.

The patent dynamically adjusts the update frequency and timing parameters based on the operational mode and accumulated skew. By changing the update interval parameters adaptively - using longer intervals during stable power-down modes and shorter intervals during transitions - the system optimizes the balance between maintaining DLL reliability and minimizing power consumption throughout different operational phases.