Memory Access Latency Adjustment for Read Buffer Stability
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Solution Overview
Problem
Memory systems face challenges in managing access command latency due to variations in data path delay caused by changes in operating conditions and process variations, leading to underflow or overflow conditions in read buffers, which affect system performance and efficiency.
Innovation Solution
The memory system incorporates an oscillator circuit to measure operating conditions and process variations, allowing the decoder to adjust access command latency based on measured metrics, using a look-up table or threshold comparisons to optimize buffer management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If access command latency is fixed, then system simplicity is maintained, but read buffer underflow or overflow conditions occur due to data path delay variations
Solution Approach 1:
The patent applies dynamics by making the access command latency adjustable rather than fixed. The latency value is dynamically modified based on measured data path delay characteristics, allowing the system to adapt to varying operating conditions and prevent buffer underflow or overflow conditions while maintaining reliability.
Solution Approach 2:
The patent implements feedback by measuring the actual data path delay using an oscillator circuit and using this measurement to adjust the access command latency. The decoder modifies the latency based on the measured delay characteristics, creating a closed-loop control system that ensures read buffer stability.
2Reliability
If access command latency is increased, then read buffer underflow is prevented, but system performance and efficiency deteriorate
Solution Approach 1:
The system dynamically adjusts latency based on actual measured delay characteristics rather than using a conservative fixed value. This allows the latency to be increased only when necessary to prevent underflow, while maintaining lower latency values when conditions allow, thus preserving system performance.
Solution Approach 2:
The patent changes the latency parameter based on measured data path delay characteristics. By adjusting the latency value according to actual operating conditions, the system prevents underflow while avoiding unnecessary performance degradation that would result from always using a high fixed latency value.
3Reliability
If manufacturer sets latency conservatively, then buffer underflow is avoided, but manufacturing precision and cost-effectiveness are reduced
Solution Approach 1:
The memory device performs self-characterization by measuring its own data path delay characteristics using an integrated oscillator circuit. This self-service approach eliminates the need for conservative manual latency settings, allowing each device to be optimized for its specific manufacturing variations while maintaining underflow avoidance.
Solution Approach 2:
The patent enables parameter changes by allowing the latency value to be adjusted based on measured delay characteristics. This permits precise optimization of the latency parameter for each device according to its actual manufacturing variations, improving both precision and cost-effectiveness compared to conservative universal settings.
Data Source
AI summary
In some implementations, a memory device may identify a count value associated with an oscillator circuit of the memory device. The memory device may determine, using the count value, whether a delay associated with a data path of the memory device satisfies a threshold. The memory device may selectively, based on determining whether the delay satisfies the threshold, modify a latency associated with a decoder of the memory device by a first value or modify the latency by a second value.