Micropump-Assisted Read Path for Stable Memory Sensing
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Solution Overview
Problem
Existing memory devices face challenges in accurately transferring data due to variability in the threshold voltage of sense transistors, particularly in all bitline schemes, which complicates the process of reading data from multiple arrays simultaneously.
Innovation Solution
Integrating a micropump within the reading hardware layer between the sense transistor and the global bitline, utilizing a series of transistors and a control logic to modulate a constant read current by activating the micropump during a read operation, thereby reducing the impact of threshold voltage variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If all bitline schemes are used to read data from multiple arrays simultaneously, then productivity is improved, but measurement precision deteriorates due to threshold voltage variability
Solution Approach 1:
A micropump is introduced as an intermediary component between the sense transistor and the global bitline. The micropump includes a capacitor that couples to the sense transistor and is activated by control logic to pump charge onto the global bitline during read operations, thereby mediating the signal transfer and compensating for threshold voltage variations.
Solution Approach 2:
The system dynamically changes the electrical parameters (charge, voltage) by activating the micropump capacitor at specific times during the read operation. This allows the system to adjust the charge pumping timing and amount to compensate for threshold voltage variability while maintaining high-speed parallel reading across multiple bitlines.
2Measurement precision
If micropump is integrated to mitigate threshold voltage variability, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The micropump functionality is merged directly into the existing reading hardware layer by integrating the capacitor and control logic within the same circuit block that reads from sense transistors. This consolidation allows the micropump to be implemented without adding separate external components, thereby reducing overall device complexity while still improving measurement precision.
Data Source
AI summary
A memory device includes an array of strings of memory cells, a local bitline coupled with a plurality of the strings of memory cells, a sense transistor having a gate terminal coupled with the local bitline, and data read path circuitry positioned at least between the sense transistor and a global bitline. The global bitline is coupled with a page buffer. A micropump is integrated within the data read path circuitry. Control logic is coupled with the data read path circuitry and to, during a read operation by the page buffer of a memory cell of the array and in response to the sense transistor turning on, activate the micropump to cause a constant read current to flow between the global bitline and the sense transistor.