NAND Flash Controller Power Interruption Protection
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Solution Overview
Problem
NAND flash memory devices used in telematics applications experience data corruption due to charge gain during power interruptions, leading to unreliable operation and failure of critical functions like eCall, which requires high reliability.
Innovation Solution
A control apparatus for NAND flash memory devices that includes a controller and an auxiliary power circuit to block commands during power instability, supply auxiliary power to complete ongoing operations, and perform controlled power-off and power-on sequences to prevent data corruption and ensure reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power supply interruption occurs during NAND flash memory operations, then data corruption due to charge gain occurs, but the memory device cannot complete ongoing program or erase operations
Solution Approach 1:
The controller detects power supply interruption in advance during ongoing program or erase operations and activates the auxiliary power circuit immediately to maintain power supply, allowing the operation to complete without data corruption. This preliminary detection and response mechanism prevents the harmful effect before it can occur.
Solution Approach 2:
The auxiliary power circuit serves as a cushioning mechanism that activates when main power is interrupted, providing backup power to complete ongoing memory operations. This beforehand prepared backup power source prevents data corruption by maintaining stable power supply during critical operation periods.
2Reliability
If the controller blocks command signals during power instability, then data corruption is prevented, but memory access is delayed
Solution Approach 1:
The controller dynamically adjusts its behavior based on power supply stability detection. During unstable power conditions, it blocks command signals to prevent data corruption. When power stabilizes, it resumes normal operations. This dynamic adaptation optimizes the balance between data integrity and access speed.
3Reliability
If auxiliary power is supplied to complete ongoing operations during power interruption, then data corruption is prevented, but power consumption increases
Solution Approach 1:
The auxiliary power circuit is activated only when power supply interruption is detected during ongoing program or erase operations. By applying counter-action (backup power) only when needed, the system prevents data corruption without unnecessarily increasing power consumption during normal operation.
Solution Approach 2:
The system changes the power supply parameter dynamically - switching from main power to auxiliary power only when interruption is detected. This parameter change ensures data integrity during critical operations while minimizing overall power consumption by activating the auxiliary circuit only when necessary.
Data Source
AI summary
A control apparatus for a NAND flash memory device including a NAND flash memory, a controller configured to generate a command signal to program, read, and erase data in the NAND flash memory, and an auxiliary power circuit configured to maintain power for operating the memory and the controller during a first time from a first time point when a voltage of a supply power is less than a preset voltage, wherein the controller is configured to block the command signal during the first time, and wherein power supplied to the memory is blocked regardless of a level of a voltage of the supply power for at least a second time from a second time point after the first time.