Source Voltage Generator for Memory Array Off-Current Suppression
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Solution Overview
Problem
Large memory arrays experience read and write errors due to interference from off current of unselected memory cells, which also deteriorate the threshold voltage margin, leading to reduced accuracy in data operations.
Innovation Solution
A memory device with a source voltage generator that outputs a first voltage when a memory cell is selected and a second voltage with a greater absolute value when all cells are unselected, reducing off current and improving threshold voltage margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the memory array size is increased to provide more capacity, then the memory capacity increases, but the off current of unselected memory cells accumulates and interferes with the on current of selected memory cells, causing read and write errors
Solution Approach 1:
The patent changes the source voltage parameter dynamically based on the selection state of memory cells. When all memory cells in a block are unselected, the source voltage generator applies a second voltage with greater absolute value to suppress off current. When at least one memory cell is selected, it applies a first voltage to allow normal operation. This parameter change resolves the contradiction by suppressing off current interference in large memory arrays while maintaining normal read/write functionality.
2Quantity of substance
If the memory array size is increased, then the memory capacity increases, but the accumulated off current deteriorates the threshold voltage margin, leading to reduced operational reliability
Solution Approach 1:
The patent dynamically adjusts the source voltage parameter based on the selection state of memory cells within blocks. When all memory cells in a block are unselected, the source voltage generator applies a second voltage with greater absolute value to suppress off current and prevent threshold voltage margin deterioration. When at least one memory cell is selected, it applies a first voltage to maintain normal operation. This resolves the contradiction by preserving threshold voltage stability in large memory arrays.
3Device complexity
If a conventional fixed source voltage is applied to all memory cells, then the circuit operation is simple, but the off current of unselected memory cells cannot be suppressed, causing interference with selected memory cell operations
Solution Approach 1:
The patent transforms the static source voltage into a dynamic parameter that changes based on memory cell selection states. The source voltage generator monitors whether memory cells in each block are selected and adjusts the source voltage accordingly - applying a first voltage when cells are selected and a second voltage with greater absolute value when all cells are unselected. This dynamic adjustment suppresses off current interference while maintaining operational simplicity through block-level control.
Data Source
AI summary
A memory device is provided. The memory device includes a plurality of memory cell blocks and a source voltage generator. Each of the memory cell blocks has at least one memory cell. The source voltage generator is coupled to the plurality of memory cell blocks and configured to cause a source voltage of the memory cell block to be a first voltage according to that a memory cell in each of the memory cell blocks is in a selected state and cause a source voltage of the memory cell block to be a second voltage according to that all memory cells in each of the memory cell blocks are in an unselected state, wherein an absolute value of the first voltage is less than an absolute value of the second voltage. In addition, an operating method of the memory device is also provided.