Semiconductor Memory Gear Down Timing Adjustment
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Solution Overview
Problem
In high-speed semiconductor memory devices like DDR4, the gear down mode complicates the adjustment of timing between the internal clock and command, leading to loss of information due to reduced frequency, making it difficult to maintain a setup/hold margin and requiring a method to compensate for this loss.
Innovation Solution
A method involving a detection unit that identifies sync pulses at both rising and falling edges of the internal clock, with a transfer unit sending this information to a memory controller to adjust the timing between the internal clock and command, ensuring accurate alignment and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal clock frequency is lowered to half the data clock frequency in gear down mode, then the setup/hold margin is improved, but the timing information between command and clock is lost
Solution Approach 1:
The patent implements a feedback mechanism where the memory device detects the sync pulse position relative to the internal clock edges and transfers this timing information back to the memory controller. The controller uses this feedback to adjust the command timing, thereby recovering the lost timing information while maintaining the reduced internal clock frequency for improved setup/hold margin.
Solution Approach 2:
The sync pulse acts as an intermediary signal that carries timing information between the data clocks and the internal clock. By detecting the sync pulse's position relative to internal clock edges and using it as a reference, the system can recover timing relationships without requiring the internal clock to run at full speed.
2Duration of action of moving object
If the internal clock frequency is reduced in gear down mode, then the pulse width is increased, but the productivity is reduced
Solution Approach 1:
The patent creates a dynamic timing adjustment system where the memory controller adapts the command timing based on the detected sync pulse position. This allows the system to operate with a reduced internal clock frequency for longer pulse widths while dynamically compensating to maintain effective productivity through optimized timing rather than fixed slow operation.
3Reliability
If the internal clock frequency is lowered to half the data clock frequency, then the setup/hold margin is ensured, but the timing adjustment complexity is increased
Solution Approach 1:
The memory device performs self-diagnosis by automatically detecting the sync pulse position relative to internal clock edges and generating timing adjustment information without external intervention. This self-service capability simplifies the overall system by having the memory device itself provide the timing information needed for adjustment, reducing the complexity of external control mechanisms.
Data Source
AI summary
A method for adjusting a timing between an internal clock and a command in a gear down mode of a memory device includes detecting a sync pulse at rising and falling edges of the internal clock, and adjusting between the internal clock of the memory device and the command according to the detection result.