Word Line Driver Segmentation for NVM Read Performance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-volatile memory circuits face challenges in maintaining high programming voltage while ensuring efficient read operation performance, particularly due to the high threshold voltage of high voltage devices, which degrades read operation performance at low voltages.
Innovation Solution
A novel word line driver architecture with dual voltage operation is introduced, utilizing a switching scheme and negative pumping to improve read performance while maintaining program performance. This architecture includes transistors, logic gates, and switches that manage voltage levels effectively, allowing for efficient high and low voltage operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage devices are used for programming NVM cells, then programming voltage can be maintained at high levels, but read operation performance degrades due to high threshold voltage
Solution Approach 1:
The word line driver is divided into two separate transistor stages: a first transistor for high voltage programming operations and a second transistor for low voltage read operations. This segmentation allows each transistor to be optimized for its specific function, with the first transistor having higher threshold voltage for programming and the second transistor having lower threshold voltage for reading, thereby resolving the contradiction between maintaining high programming voltage and ensuring good read performance.
Solution Approach 2:
The patent employs dynamic switching between different transistor stages based on the operational mode. A switch circuit dynamically connects the appropriate transistor to the word line based on whether programming or reading is required, allowing the system to adapt its voltage handling characteristics in real-time. This dynamic configuration enables high voltage programming when needed while maintaining low voltage read performance.
2Device complexity
If single voltage operation is used for word line driver, then device complexity is reduced, but both high voltage programming and low voltage read operations cannot be efficiently performed
Solution Approach 1:
The word line driver is segmented into multiple transistor stages, each dedicated to specific voltage operations. The first transistor handles high voltage programming while the second transistor handles low voltage reading, allowing the system to perform both operations efficiently without requiring a single complex multi-mode transistor design.
Solution Approach 2:
The word line driver circuit is designed with multi-functionality by incorporating both high voltage and low voltage operation capabilities within a single integrated circuit. The switch circuit enables the same circuit to perform both programming and reading operations by dynamically selecting the appropriate transistor stage, achieving universal functionality without proportionally increasing complexity.
Data Source
AI summary
A word line driver includes a first transistor electrically connected to a first voltage supply node and a word line, a second transistor electrically connected to a second voltage supply node and the word line, a first switch electrically connected to the first voltage supply node and a bulk electrode of the second transistor, and a second switch electrically connected to the second voltage supply node and the bulk electrode of the second transistor.