Gain Cell Storage Device Cancel Circuit Leakage Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In dynamic random access memory (DRAM) systems, particularly in gain-cell DRAMs, the miniaturization of memory cells makes it challenging to maintain the required capacitance, leading to increased leakage currents that can result in noise margin reduction and incorrect data reading.
Innovation Solution
A storage device with a gain-cell memory cell configuration, including a write transistor and a read transistor, where the channel formation region of the write transistor incorporates a metal oxide, and a cancel circuit is used to compensate for leakage currents, improving the noise margin and reducing incorrect data reading by canceling out leakage current effects on the bit line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If memory cells are miniaturized to increase integration density, then the number of elements per unit area increases, but the capacitance of the capacitor decreases making it difficult to maintain required capacitance values
Solution Approach 1:
The memory cell is divided into a gain cell structure with separate write transistor and read transistor, allowing independent optimization of write and read operations. This segmentation enables the capacitor to be smaller while using the read transistor to amplify the read signal, thus maintaining required capacitance values even in miniaturized cells
Solution Approach 2:
A cancel circuit is introduced as an intermediary component to compensate for leakage current in the read bit line. The cancel circuit supplies current to counteract the leakage current from unselected cells, thereby maintaining signal integrity and enabling accurate data reading despite miniaturization effects
2Reliability
If gain cell structure is used to reduce capacitor capacitance requirements, then the capacitance value can be reduced, but leakage current from unselected cells increases causing incorrect data reading
Solution Approach 1:
The cancel circuit acts as an intermediary that supplies compensation current to the read bit line. This compensation current counteracts the leakage current from unselected gain cells, preventing incorrect data reading and maintaining data reading accuracy even when using reduced capacitance values
Solution Approach 2:
The cancel circuit performs preliminary compensation for leakage current before the actual read operation completes. By supplying current to cancel the leakage effect in advance, the system prevents the leakage from causing incorrect data reading, thus maintaining data integrity
3Productivity
If miniaturized memory cells are used, then integration density increases, but noise margin decreases due to increased leakage current effects
Solution Approach 1:
The cancel circuit serves as a mediator that compensates for leakage current effects in miniaturized cells. By supplying compensation current to the read bit line, it maintains the noise margin despite the increased leakage current effects from miniaturization, thus preserving signal integrity in high-density memory structures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively enhances the noise margin and reduces incorrect data reading by suppressing leakage currents from unselected cells, thereby improving the reliability of data reading operations in miniaturized memory cells.
Implementation Method 1
a channel formation region of the write transistor includes a metal oxide
Implementation Method 2
The cancel circuit has a function of supplying, to the read bit line, current for canceling leakage current supplied to the read bit line from the gain cell
Data Source
AI summary
A data reading error is reduced. A memory cell array in a storage device includes a write word line, a read word line, a write bit line, a read bit line, a source line, and a gain cell. For example, a read transistor in the gain cell can include a metal oxide in a channel formation region. A cancel circuit is electrically connected to the read bit line. The cancel circuit has a function of supplying, to the read bit line, current for canceling leakage current supplied to the read bit line from the gain cell in a non-selected state. In read operation, a potential change of the read bit line due to leakage current is compensated for by the current from the cancel circuit, so that a data reading error is reduced.