Memory Recovery by Disabling Drive-Strength Mismatched Dies
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Solution Overview
Problem
Memory devices in a stack or module often have mismatched drive strengths due to manufacturing variations, leading to package or module failures and performance issues, even after conventional recovery operations.
Innovation Solution
Measure the internal drive strengths of memory devices and selectively disable a subset with the most mismatched drive strengths to maintain optimal performance by using counting logic and storing the results in mode registers for later retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional recovery operations are used to disable a subset of memory devices, then package or module failures can be addressed, but the remaining devices still have mismatched drive strengths that negatively impact performance
Solution Approach 1:
The patent applies preliminary action by measuring the drive strength of each memory device before the recovery operation and storing this information in mode registers. This advance measurement and classification allows the recovery operation to selectively disable devices based on pre-characterized drive strength mismatches, ensuring that the remaining devices have well-matched drive strengths and optimal performance is maintained.
2Ease of manufacture
If memory devices with mismatched drive strengths are used, then manufacturing variation is accepted, but performance issues and failures occur
Solution Approach 1:
The patent applies local quality by individually characterizing the drive strength of each specific memory device and using this device-specific information to determine its suitability for the recovered configuration. Instead of treating all devices uniformly, the system assigns different roles based on each device's actual drive strength characteristics, ensuring optimal performance for each individual device in the recovered system.
3Manufacturing precision
If drive strength measurement and classification is implemented, then optimal device selection for recovery is achieved, but additional measurement and storage operations are required
Solution Approach 1:
The patent applies universality by using mode registers that serve multiple functions: they store drive strength classification data, enable device identification, and support the recovery operation. This multi-functional use of existing register structures avoids adding separate dedicated measurement and storage hardware, thereby reducing the increase in device complexity while achieving precise drive strength matching.
Data Source
AI summary
An apparatus is provided, comprising a controller, a plurality of memory devices operably connected to the controller, circuitry configured to measure a performance metric for each of the plurality of memory devices, and circuitry configured to select, based upon the measured performance metric, a subset of the plurality of memory devices to disable in response to a recovery command. Information corresponding to the selected subset can be stored in a mode register of the apparatus, and the apparatus can further comprise circuitry configured, in response to a recovery command, to disable the subset of the plurality of memory devices.