Programmable Memory Die Refresh Stagger to Reduce Peak Current
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Solution Overview
Problem
Memory systems experience significant current demand peaks during refresh operations, which can lead to system reboots and inefficiencies, particularly in systems with multiple memory dies.
Innovation Solution
Memory devices are assigned to staggered refresh groups with timed delays to distribute current draw over time, using fuse arrays and refresh group detect circuitry to manage refresh operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If memory devices perform refresh operations simultaneously, then data retention is maintained, but peak current demand increases significantly causing system reboots
Solution Approach 1:
The patent divides the memory system into multiple refresh groups (first refresh group and second refresh group) where devices are assigned to different groups based on their refresh characteristics. Each group performs refresh operations at different times, segmenting the overall refresh current demand into multiple smaller peaks rather than one large simultaneous peak, thereby reducing the maximum current demand while maintaining data retention.
2Power
If memory devices are assigned to different refresh groups with staggered timing, then peak current demand is reduced, but system complexity increases due to additional control circuitry
Solution Approach 1:
The patent implements self-service through automatic refresh group assignment where memory devices autonomously determine their refresh group based on detected characteristics (such as refresh failure patterns or performance metrics) without requiring external controller intervention. The devices self-organize into appropriate refresh groups and autonomously execute staggered refresh operations, eliminating the need for complex external control circuitry while achieving current demand reduction.
3Ease of operation
If all memory devices refresh at the same time, then refresh operations are simple to manage, but power supply utilization is inefficient due to high peak demands
Solution Approach 1:
The patent implements periodic action by organizing memory devices into refresh groups that perform refresh operations in alternating time periods. The first refresh group operates during one time period while the second refresh group operates during a subsequent time period, creating a periodic pattern of refresh operations. This distributes power consumption over time, improving power supply utilization efficiency while maintaining manageable operation through automated group assignment.
Data Source
AI summary
Memory devices and systems with configurable die refresh stagger, and associated methods, are disclosed herein. In one embodiment, a memory system includes two or more memory dies. At least one memory die includes a fuse array storing refresh information that specifies a refresh group of the memory die. In these and other embodiments, at least one memory die includes a refresh group terminal and refresh group detect circuitry electrically connected to the refresh group terminal. The at least one memory die is configured to detect a refresh group of the memory die and to delay its refresh operation by a time delay corresponding to the refresh group. In this manner, refresh operations of the two or more memory dies can be staggered to reduce peak current demand of the memory system.