Selectable Wordline Driver with Centralized Local Wordline Control
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Solution Overview
Problem
Advanced DRAM devices, such as 3DDRAM, require large and numerous drivers to handle a wide range of voltages, leading to increased size and lower density of storage nodes due to drivers being included at each tier.
Innovation Solution
Implement driver circuitry that selectively controls local wordlines using global wordline voltages and wordline select voltages, centralizing voltage generation circuitry and reducing the number of components, thereby allowing for a more compact memory device design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If drivers with larger and more numerous components are used to provide large ranges of currents and voltages, then the driving capability is improved, but the footprint of the memory device increases
Solution Approach 1:
The patent segments the driver functionality into two separate components: a first driver that provides first currents and voltages, and a second driver that provides second currents and voltages. This segmentation allows each driver to be optimized for specific voltage ranges, reducing the overall component count and footprint while maintaining the capability to provide a wide range of driving voltages to wordlines and digitlines.
2Power
If drivers are included at each tier of vertically stacked memory device, then the driving capability for each tier is improved, but the density of storage elements decreases
Solution Approach 1:
The patent merges driver functionality by implementing shared drivers that can serve multiple tiers or regions of the vertically stacked memory device. The first driver and second driver are configured to provide currents and voltages to multiple wordlines and digitlines across different tiers, eliminating the need for separate drivers at each tier and thereby increasing storage element density.
3Device complexity
If a single driver provides all currents and voltages to multiple wordlines, then the device complexity is reduced, but the ability to selectively control individual wordlines is limited
Solution Approach 1:
The patent segments the driving functionality into specialized first and second drivers, each optimized for specific voltage ranges. This segmentation enables selective control of individual wordlines by choosing which driver to activate based on the required voltage level, thereby maintaining high adaptability while simplifying the overall device architecture compared to having multiple full-featured drivers.
Data Source
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AI summary
A memory device includes one or more memory cells, a global wordline, a plurality of local wordlines each coupled to respective memory cells of the one or more memory cells, a wordline transistor coupled to the global wordline and to a local wordline of the plurality of wordlines, and voltage generation circuitry. The voltage generation circuitry may provide a global wordline voltage to the global wordline and provide a wordline select control signal to the wordline transistor. The wordline transistor may pull a local wordline voltage of the local wordline to the global wordline voltage based on the wordline select control signal.