Semiconductor Storage Driver Voltage Compensation for Word Line Sections
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Solution Overview
Problem
Semiconductor storage devices face significant voltage variations between selected memory cells when concurrently selecting cells at the front and rear ends of a word line, leading to poor operation.
Innovation Solution
A semiconductor storage device with a selection unit that concurrently selects at least two memory cells in the same section, applying different voltages through parallel wiring lines based on the length of the current path to minimize voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If memory cells at the front end and rear end of a word line are concurrently selected to minimize voltage drop, then the voltage drop in the word line is reduced, but the voltage variation between selected memory cells becomes significant
Solution Approach 1:
The word line is divided into multiple sections (first section, second section, etc.) along the first direction. Each section is assigned a different voltage level by the driver, with sections farther from the reference potential end receiving higher voltages to compensate for voltage drop. This segmentation allows concurrent selection of memory cells across different sections while maintaining uniform voltage levels, resolving the contradiction between minimizing voltage drop and reducing voltage variation.
2Reliability
If different voltages are applied to different sections of the word line, then voltage variation between selected memory cells is reduced, but the device complexity increases
Solution Approach 1:
The driver applies different voltage levels to different sections of the word line based on their local characteristics (distance from the reference potential end). Each section receives a voltage level appropriate to its position, with sections farther away receiving higher voltages. This local quality approach compensates for position-dependent voltage drops while maintaining a relatively simple driver structure that only needs to manage a few discrete voltage levels.
Data Source
AI summary
A semiconductor storage device includes first wiring lines extending in a first direction, second wiring lines extending in a second direction, memory cells at intersections of the first and second wiring lines. A selection unit concurrently selects, as selected memory cells, at least two memory cells that are between one of the first wiring lines and one of the second wiring lines and divided into a plurality of contiguous sections along the first wiring line, and a driver applies a voltage to selected memory cells through the first and second wiring lines. The at least two memory cells are located in the same section and the driver applies a first voltage when the selected memory cells are in a first section, and applies a second voltage, different from the first voltage, when the selected memory cells are in a second section.