Bit Line Pre-Charge Timing With Internal-External Clock Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Memory cell access operations are prone to signal and data errors due to timing variations in the bit line pre-charge window, which can occur when the margin is inadequate, leading to premature activation of word line signals.
Innovation Solution
A bit line pre-charge circuit that adjusts the frequency of the clock signal using an internal or external clock based on the pulse width of the clock signal, ensuring the bit line pre-charge window is within an acceptable margin by employing a tracking circuit and switch mechanism to control the switch circuit state, thereby synchronizing the bit line pre-charge and word line activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bit line pre-charge window margin is reduced to improve speed, then productivity increases, but reliability deteriorates due to premature word line activation and signal errors
Solution Approach 1:
The patent employs a feedback mechanism where the actual bit line pre-charge window is measured and compared against a target window. A control signal adjusts the pre-charge timing based on this comparison, ensuring the window remains within an acceptable margin even when operating at high speeds. This closed-loop control prevents premature word line activation while maintaining productivity.
2Device complexity
If fixed clock timing is used to simplify control, then device complexity is reduced, but reliability deteriorates due to timing variations causing premature word line activation
Solution Approach 1:
The patent transitions from fixed clock timing to dynamic timing adjustment. The system continuously monitors the actual pre-charge window duration and adjusts the clock timing accordingly. This dynamic adaptation allows the system to maintain precise timing margins despite process variations, temperature changes, or voltage fluctuations, thereby improving reliability without requiring overly complex control circuits.
3Reliability
If the bit line pre-charge window is extended to ensure proper charging, then reliability improves, but productivity deteriorates due to increased access time
Solution Approach 1:
The patent dynamically adjusts the bit line pre-charge window duration based on actual operating conditions. Rather than using a fixed extended window that always ensures charging but slows access, the system monitors charging completeness and adjusts the window length in real-time. This allows the system to achieve reliable charging with the minimum necessary time, optimizing the balance between reliability and productivity.
Data Source
AI summary
A bit line is pre-charged based on a clock signal internal to a bit line pre-charge circuit when a bit line pre-charge window is within a margin of a predetermined pre-charge window. A bit line is pre-charged based on a clock signal external to the bit line pre-charge circuit when the bit line pre-charge window is outside the margin of the predetermined pre-charge window.