Memory Power-Loss Notification for Reliable Data Flush Shutdown
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Solution Overview
Problem
Memory systems without integrated power loss backup circuitry face challenges in notifying and ensuring proper shutdown during asynchronous power loss events, particularly in small modules with both volatile and non-volatile memory, leading to potential data loss and system instability.
Innovation Solution
Implementing a power loss notification (PLN) function and power loss acknowledgment (PLA) mechanism in memory devices, coupled with external power management circuitry, to ensure timely shutdown and data flushing by verifying backup power duration and logging PLN signals to detect errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If memory systems use external power management circuitry instead of integrated backup circuitry, then device size is reduced and manufacturing flexibility is improved, but the ability to detect and respond to power loss events deteriorates
Solution Approach 1:
The system separates power management functions into external power management circuitry and memory module, with the external circuitry handling power loss detection and notification while the module handles data flushing and shutdown operations. This segmentation allows size reduction while maintaining detection capability through the external circuitry.
Solution Approach 2:
A power loss notification (PLN) signal acts as an intermediary communication mechanism between the external power management circuitry and the memory module. The PLN signal conveys power loss status without requiring integrated backup circuitry, enabling reliable power loss detection across the system boundary.
2Reliability
If the memory device performs comprehensive shutdown operations including data flushing, then data retention is improved, but shutdown time increases which may exceed backup power duration
Solution Approach 1:
The system performs preliminary actions by flushing data to non-volatile memory before complete power loss occurs. The external power management circuitry provides backup power and sends PLN notifications that trigger data flushing operations while power is still available, ensuring data retention without requiring the entire shutdown process to complete under backup power.
Solution Approach 2:
The power loss acknowledgment (PLA) signal provides feedback between the memory module and external power management circuitry, indicating whether the module has successfully completed shutdown operations. This feedback mechanism allows the system to verify data flushing completion and coordinate power removal timing to match actual shutdown progress.
3Reliability
If the system logs PLN signal samples to verify backup power duration, then power loss notification reliability is improved, but processing complexity and power consumption increase
Solution Approach 1:
The memory module autonomously samples and logs PLN signal levels during shutdown operations without requiring external assistance. This self-service approach to verification simplifies the overall system by distributing the logging function to the module itself, reducing external circuitry complexity while maintaining reliable backup power duration verification.
Data Source
AI summary
Methods, systems, and devices for power loss notification (PLN) power processing for memory systems are described. A memory device may be coupled with power loss backup circuitry that is external to the memory device. The power loss backup circuitry may detect a loss of a power supply and may utilize a PLN to notify the memory device of the power loss. The power loss backup circuitry may provide a backup power supply to the memory device while the memory device prepares for shutdown. The memory device may use the PLN, a power loss acknowledgment (PLA) indication, and a logging mechanism to verify that a duration over which the backup power is supplied is sufficient to support a complete shutdown operation, including the reliable flush of data to non-volatile memory without error. The PLN and logging mechanism described herein provides for reliable and efficient power loss processing.