Semiconductor Memory Device Dynamic State Control
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Solution Overview
Problem
Current semiconductor memory devices with mixed volatile and nonvolatile memory cell areas face challenges in dynamically adjusting the memory cell characteristics to optimize data retention and operation speed, leading to inefficient power consumption and limited flexibility in data access.
Innovation Solution
A semiconductor memory device that utilizes a signal line driver and control module to dynamically control the voltage and current applied to memory cells, transitioning them between volatile and nonvolatile states based on data traffic, allowing for efficient switching between fast data access and long-term data retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If memory cells are set to volatile state for fast access, then operation speed is improved, but data retention deteriorates
Solution Approach 1:
The patent applies dynamics by enabling memory cells to transition between volatile and nonvolatile states based on access patterns. The control module dynamically adjusts the state of each memory cell or group of cells, allowing the system to optimize between speed and retention on-demand rather than being static. This is achieved through applying different voltages to control the resistance state of memory cells, enabling them to switch between volatile (low resistance) and nonvolatile (high resistance) characteristics.
Solution Approach 2:
The patent utilizes parameter changes by modifying the resistance characteristics of memory cells through voltage control. By applying specific voltages during write operations, the memory cells change their resistance state, which determines whether they operate in volatile or nonvolatile mode. This parameter change allows the same physical memory cell to exhibit different electrical characteristics suitable for different operational requirements.
2Reliability
If memory cells are set to nonvolatile state for data retention, then data retention is improved, but operation speed deteriorates
Solution Approach 1:
The system dynamically transitions memory cells from nonvolatile to volatile state when data is to be accessed frequently. The control module monitors access patterns and applies appropriate voltages to change the resistance state of memory cells, enabling them to switch from high resistance (nonvolatile) to low resistance (volatile) state before access operations, thereby optimizing read/write speed when needed.
Solution Approach 2:
The patent applies preliminary action by pre-loading frequently accessed data from nonvolatile memory cells into volatile memory cells or buffer areas before actual access operations. This preliminary transition ensures that hot data is already in the fast-access state when needed, reducing the impact of state switching on overall system performance.
3Speed
If volatile memory cell area is increased for fast access, then operation speed is improved, but power consumption deteriorates due to refresh operations
Solution Approach 1:
The patent applies local quality by dividing the memory system into different regions with different characteristics - volatile memory cell areas for frequently accessed data requiring fast access, and nonvolatile memory cell areas for less frequently accessed data. This spatial differentiation allows each region to operate in its optimal state, with volatile regions consuming power only when actively accessed rather than requiring continuous refresh operations across the entire memory array.
Solution Approach 2:
The memory cell array is segmented into multiple volatile memory cell areas and nonvolatile memory cell areas. This segmentation allows the system to distribute data strategically - placing frequently accessed data in volatile regions and less frequently accessed data in nonvolatile regions - thereby reducing the overall refresh power consumption while maintaining fast access performance for critical data.
4Reliability
If nonvolatile memory cell area is increased for data retention, then data retention is improved, but operation speed deteriorates
Solution Approach 1:
The system implements local quality by creating specialized nonvolatile memory regions for data requiring long-term retention, while maintaining separate volatile regions for active data processing. This allows the nonvolatile areas to be optimized for retention without compromising the speed of volatile areas, as each region operates independently in its optimal performance mode.
Solution Approach 2:
The memory architecture segments the cell array into distinct volatile and nonvolatile sections, enabling independent optimization of each segment. Nonvolatile segments can be larger and dedicated to archival storage, while volatile segments handle active processing, thereby achieving both strong data retention and fast operation speeds simultaneously through proper data placement and access management.
5Ease of manufacture
If fixed volatile and nonvolatile memory cell areas are set before shipping, then manufacturing simplicity is improved, but adaptability deteriorates
Solution Approach 1:
The patent applies universality by designing memory cells that can function in both volatile and nonvolatile modes depending on applied voltage conditions. Rather than manufacturing completely separate volatile and nonvolatile memory structures, the same memory cell design can be dynamically configured to serve either function, providing manufacturing simplicity while achieving operational versatility and adaptability.
Solution Approach 2:
The system achieves adaptability through dynamic configuration capabilities - the control module can adjust the operational state of memory cells based on real-time access patterns and workload requirements. This allows the memory system to adapt its characteristics (volatile vs. nonvolatile ratio, access patterns, retention periods) dynamically, providing flexibility comparable to having separate dedicated memory types while maintaining manufacturing simplicity through a unified cell design.
Data Source
AI summary
According to one embodiment, a semiconductor memory device includes first cells, first lines, second lines, a first cell array, and a signal driver. The first cell has in either a first state or a second state. Retention time in the second state is longer than in the first state. The first cell array has the first cells formed in a matrix the individuals. The first cells are electrically connected by the first, second lines. The signal driver drives the first cells. The signal driver causes the first cells to transition to either the first state or the second state by controlling any one of a voltage, a current, and a charge amount applied to the first cells, or a combination of these, and waveforms of the voltage, current, and charge amount and/or the length of transfer time of at least one of the voltage, current, and charge amount.