Memory Subsystem Background Calibration via Duplicate Data Path
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Memory subsystems face challenges in efficiently performing calibrations during normal operations without disrupting data traffic, as periodic calibrations can be resource-intensive and may not utilize available data effectively, leading to reduced system availability during high traffic times.
Innovation Solution
A memory subsystem with a memory controller and calibration circuitry that performs background calibrations using a duplicate data path to adjust delay locked loops, allowing for periodic calibration cancellation when sufficient data is read, ensuring accurate signal sampling and reducing system unavailability during high traffic periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If periodic calibrations are performed to ensure accurate signal sampling, then measurement precision is improved, but system availability deteriorates during high traffic periods
Solution Approach 1:
The patent performs calibration in advance during low-traffic periods or background operations, so that when high-traffic periods occur, the calibration is already complete and the system can operate without interruption. This eliminates the need to pause data traffic for calibration during critical periods.
Solution Approach 2:
The patent introduces a duplicate data path as an intermediary calibration path that operates independently from the functional data path. This allows calibration to proceed on the duplicate path without affecting normal data traffic on the functional path, thereby maintaining system availability while ensuring calibration accuracy.
2Reliability
If periodic calibrations are performed to maintain signal integrity, then reliability is improved, but productivity deteriorates due to reduced system availability
Solution Approach 1:
The patent segments the data path into a functional data path for normal operations and a duplicate data path for calibration. This segmentation allows calibration activities to occur on the duplicate path without interrupting data processing on the functional path, thereby maintaining both reliability and productivity simultaneously.
Solution Approach 2:
The duplicate data path serves as an intermediary that absorbs the calibration burden, allowing the functional data path to continue processing data without interruption. This intermediary structure ensures that reliability maintenance activities do not compromise productivity.
3Measurement precision
If calibration uses dedicated calibration data, then measurement precision is improved, but loss of substance increases due to unnecessary data traffic generation
Solution Approach 1:
The patent makes the data path serve multiple functions: it handles both normal data traffic and calibration activities. By using the duplicate data path for calibration while it mirrors the functional path, the system achieves calibration accuracy without generating separate calibration traffic, thereby reducing overall data traffic overhead.
Solution Approach 2:
The system uses its own existing data infrastructure (the duplicate data path) to perform calibration, rather than introducing separate calibration mechanisms. This self-service approach allows calibration to occur using the same resources already allocated for data processing, eliminating the need for additional calibration-specific data traffic.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances system availability by leveraging normal data traffic for calibration, reducing the performance impact of periodic calibrations, especially during high memory usage, and ensuring accurate data sampling by comparing data from functional and duplicate paths.
Implementation Method 1
The calibration circuit calibrates a first delay locked loop (DLL) in the duplicate data path
Data Source
AI summary
A method and apparatus for performing a background calibration in a memory subsystem is disclosed. A memory subsystem includes a memory controller coupled to a memory. The memory controller is coupled to receive data during reads from the memory on a functional data path and a duplicate data path. The memory controller further includes calibration circuitry. During reads of data conducted during normal operation, the calibration circuit calibrates a first delay locked loop (DLL) in the duplicate data path. A second DLL, in the functional data path, may be adjusted based on the calibrations conducted in the duplicate data path.