Flash Memory Protection Circuit Using Capacitor Backup
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Solution Overview
Problem
NAND flash memory is prone to data destruction during power interruptions or write protection status changes, leading to potential system crashes or errors, especially in MLC structures, as existing solutions fail to effectively prevent data loss during write procedures.
Innovation Solution
A protection circuit comprising a capacitor and a switch connected between the power supply pin and ground, which charges during stable power and provides backup power when interruptions occur, and a power supply system that maintains write protection pin voltages using capacitors and switches to prevent data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power supply is interrupted during write procedure, then data being written is destroyed, but adding protection circuit increases device complexity
Solution Approach 1:
The capacitor is pre-charged to a first voltage level before the write operation begins. This preliminary charging ensures that when power is interrupted during the write procedure, the capacitor already has sufficient energy to maintain the power supply pin voltage and allow the write operation to complete successfully, thus preventing data destruction without requiring complex real-time detection circuits.
Solution Approach 2:
The protection circuit uses a capacitor to store energy in advance, creating a voltage buffer that cushions against power supply interruptions. This beforehand cushioning provides a safety margin that maintains adequate voltage levels during the critical write period even when external power is interrupted, thereby protecting data integrity with a relatively simple circuit configuration.
2Reliability
If write protection pin is switched during write procedure, then write procedure is interrupted and data is destroyed, but adding protection mechanism increases device complexity
Solution Approach 1:
The capacitor is charged to a first voltage level before the write operation starts, creating a preliminary energy reserve. This pre-charged capacitor maintains the power supply pin voltage throughout the write procedure, preventing unintended write protection activation and ensuring write operation completeness without requiring complex monitoring or control circuits.
3Ease of manufacture
If MLC structure is used to reduce production cost, then more data bits per storage unit are stored, but power interruption causes more severe data loss
Solution Approach 1:
The capacitor is pre-charged to a first voltage level before the write operation begins, creating an energy buffer that maintains power supply stability throughout the write procedure. This preliminary action protects against power interruptions that would otherwise cause severe data loss in MLC structures, thereby enabling cost-effective MLC implementation without sacrificing reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures the completion of write procedures in NAND flash memory without data destruction by maintaining power and write protection voltages, even during power outages or accidental write protection status changes, thereby preventing system failures.
Implementation Method 1
a capacitor and a switch. The capacitor is electrically connected between a power supply pin of a flash memory and a ground point
Data Source
AI summary
A protection circuit, applied to a flash memory including a power supply pin, includes a capacitor and a switch. A power supply provides a reference voltage. The capacitor is electrically connected to the power supply pin and a ground point. The switch is electrically connected between the power supply pin and the power supply. When the reference voltage is higher than a threshold voltage, the switch is turned on, such that the reference voltage is inputted into the power pin via the switch. When the reference voltage is lower than the threshold voltage, the switch is turned off.