Memory Signal Calibration via Delayed Sampling for DDR Timing

The patent performs preliminary calibration of the DQS_EN signal timing by sampling the DQ signal at multiple different timing positions and determining the optimal timing in advance. This preliminary action creates a timing reference that compensates for voltage and temperature variations, allowing the system to maintain accurate sampling without requiring real-time adjustment during normal operation.

The patent implements a feedback mechanism where the sampling circuit samples the DQ signal at multiple timing positions, compares the sampling results, and uses this feedback information to determine the optimal timing for the DQS_EN signal. This feedback loop continuously adapts to voltage and temperature changes, maintaining timing accuracy under varying conditions.

The patent introduces an intermediary calibration mechanism that uses multiple sampling positions and comparison logic to determine the optimal timing. Instead of relying solely on a simple delay circuit, the intermediary calibration process measures the actual signal characteristics and adjusts the timing accordingly, achieving high precision without significantly increasing overall device complexity.

The patent segments the timing determination process into multiple discrete sampling positions. By dividing the timing adjustment into distinct steps (first timing position, second timing position, etc.), the system can precisely identify the optimal timing point while using relatively simple circuitry at each segment, avoiding the need for a complex continuous adjustment mechanism.