Flash Memory Write Protection Using Volatile and Non-Volatile Latches
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Solution Overview
Problem
Conventional flash memory devices lack a reliable method to persistently manage and update the lock/write state of memory blocks, leading to potential data loss during power interruptions and errors in register entries.
Innovation Solution
A flash memory device with a protection controller that uses a combination of volatile and non-volatile storage to generate a protection flag signal, enabling or disabling write operations based on the comparison of temporary and persistent data, ensuring that protected/accessible states are accurately maintained across power cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If volatile latches are used to store lock/write state data in block control circuit, then ease of operation is improved, but reliability deteriorates due to data loss during power interruptions
Solution Approach 1:
The patent changes the storage medium parameter from volatile (latches) to non-volatile (memory cells) to preserve lock/write state data during power interruptions. This allows the protection state to be maintained without continuous power, resolving the reliability issue while keeping the system easy to operate through standard memory write operations.
Solution Approach 2:
The patent creates a copy of the lock/write state data from volatile latches to non-volatile memory cells. This copying mechanism ensures that the protection state information is preserved reliably in non-volatile storage while the original volatile storage can still be easily updated, thus maintaining both reliability and ease of operation.
2Reliability
If non-volatile memory cells are used to store persistent protected/accessible data, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the functionality of separate volatile and non-volatile storage systems into a unified protection mechanism. The block control circuit integrates both latch circuit (volatile) and memory cell array (non-volatile) to work together, where the memory cells store persistent protection state data that supplements the volatile latch storage, achieving reliability without excessive complexity.
Solution Approach 2:
The patent segments the storage function into two parts: volatile latches for temporary/operational storage and non-volatile memory cells for persistent storage. This segmentation allows each component to perform its specialized function efficiently, with the memory cells providing reliable long-term storage of protection state data without overwhelming the overall device complexity.
3Reliability
If block-based architecture is used with protection schemes, then data integrity is improved, but ease of operation deteriorates due to restricted access to protected blocks
Solution Approach 1:
The patent implements a dynamic protection mechanism where the lock/write state of memory blocks can be changed from protected to accessible and vice versa. The protection state is stored in memory cells and can be updated through standard write operations, allowing the system to dynamically adjust protection levels based on operational needs while maintaining data integrity when protected.
Solution Approach 2:
The patent enables the memory system to self-manage its protection state through standard write operations. The lock/write state data in memory cells can be updated using conventional memory write procedures, allowing the system to automatically maintain and update its own protection configuration without requiring external control logic or complex management procedures.
Data Source
AI summary
A flash memory device and a related method of write protecting data are disclosed. The flash memory device includes a protection controller having a latch circuit storing temporary protected/accessible data, a cell array storing persistent protected/accessible data, a write controller altering the persistent protected/accessible data, and a latch controller altering the temporary protected/accessible data.