Multi-stage voltage control for open block current reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flash storage devices face challenges in maintaining optimal power consumption and read performance due to higher peak and average currents when reading data from open blocks, which can lead to voltage drops and impact device functionality.
Innovation Solution
Implementing ramp rate and multi-stage voltage control in the controller to apply read voltages differently based on whether blocks are open or closed, and varying the ramp rates and stages depending on the programming state of the blocks, thereby reducing peak and average current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If read voltage is applied to word lines in open blocks, then data can be read from the block, but peak and average current increase causing voltage drops that affect device functionality
Solution Approach 1:
The patent segments the voltage application process into multiple stages with different ramp rates. For open blocks, it uses a first number of stages with a first ramp rate, and for closed blocks, it uses a second number of stages with a second ramp rate. This segmentation allows optimized current control for each block type, preventing voltage drops while maintaining read capability.
Solution Approach 2:
The patent dynamically adjusts the voltage ramp rate and number of stages based on the block state (open or closed). The controller determines whether a block is open or closed and applies different ramp rates accordingly. This dynamic adaptation resolves the contradiction by matching the voltage application strategy to the actual block condition, ensuring stable voltages during reads.
2Productivity
If read voltage is applied with high ramp rate to improve read speed, then productivity increases, but peak current increases causing voltage drops
Solution Approach 1:
The patent uses dynamic ramp rate adjustment based on block state. For closed blocks where higher currents are tolerable, it applies a faster second ramp rate to improve read speed. For open blocks where voltage stability is critical, it uses a slower first ramp rate to prevent voltage drops. This dynamic approach optimizes both read speed and power consumption based on actual conditions.
Solution Approach 2:
The patent changes the voltage ramp rate parameter based on the block's programming state. By detecting whether blocks are open or closed, the system adjusts the ramp rate parameter to balance read speed and peak current. This parameter adaptation resolves the contradiction between fast reads and low peak current.
3Reliability
If multi-stage voltage control is implemented to reduce peak current, then voltage stability improves, but device complexity increases
Solution Approach 1:
The patent segments voltage control into multiple stages with different ramp rates based on block state. This segmentation provides fine-grained control over voltage application, improving voltage stability during reads from open blocks. The segmented approach manages complexity by organizing control into distinct, manageable stages rather than a single complex control mechanism.
Solution Approach 2:
The patent implements feedback by detecting the block state (open or closed) and using this information to adjust the voltage ramp rate and number of stages. This feedback mechanism enables the controller to automatically adapt its behavior, improving voltage stability without requiring complex manual configuration. The feedback loop simplifies the overall control strategy by making it responsive to actual block conditions.
Data Source
AI summary
Aspects of a storage device including a memory and a controller are provided which allow for reduction of current in open blocks during read operations using multi-stage read voltage control. The controller determines whether a block is open or closed. If the block is closed, the controller causes a read voltage to be applied to one of the block's word lines. If the block is open, the controller causes a read voltage to be applied to another of the block's word lines in a number of stages. The controller further causes a read voltage to be applied to another word line of the open block in a different number of stages. Thus, read voltages for open blocks may ramp in multiple stages in contrast to read voltages for closed blocks, as well as ramp in different numbers of stages for different word lines in open blocks.