Sense Amplifier Circuitry Area Reduction via Transistor Segmentation
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Solution Overview
Problem
The existing flash memory devices face challenges in reducing the area occupied by sense amplifier circuitry, which consumes a significant portion of the memory device's area due to the use of long body transistors, while maintaining low level and precise reference currents for high memory density and low power consumption.
Innovation Solution
The use of short body transistors in sense amplifier circuitry, which consume less area, combined with a gate cycling mechanism to adjust the reference current, allows for effective current injection similar to long body transistors, thereby reducing the overall area required for sense amplifier circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If long body transistors are used in reference current generators, then precise and low level reference current is achieved, but area consumption increases significantly
Solution Approach 1:
The reference current generation function is segmented between two types of transistors: short body transistors provide the basic current generation with reduced area, while long body transistors are used selectively in only some sense amplifiers to provide precision reference current. This segmentation allows the system to achieve precise reference current where needed while minimizing overall area consumption across all 64,000 sense amplifiers.
Solution Approach 2:
Different transistor body lengths are applied to different sense amplifiers based on their specific requirements. Some sense amplifiers use long body transistors for high-precision reference current generation, while others use short body transistors for area-efficient operation. This local differentiation optimizes the balance between precision and area consumption across the entire memory device.
2Use of energy by stationary object
If long body transistors are used in each sense amplifier, then low level reference current is maintained, but overall current consumption increases due to parallel operation
Solution Approach 1:
The sense amplifier population is segmented into different groups based on their reference current requirements. Only a subset of sense amplifiers uses long body transistors to generate low-level precise reference currents, while the majority use short body transistors with higher current. This segmentation reduces the cumulative current consumption across all parallel sense amplifiers while maintaining precision where critical.
3Area of stationary object
If short body transistors are used to reduce area, then area consumption decreases, but reference current precision deteriorates
Solution Approach 1:
Short body transistors are deployed in sense amplifiers where area is critical and precision requirements are moderate, while long body transistors are strategically placed in sense amplifiers that require high-precision reference current for accurate data sensing. This localized application of different transistor types optimizes the area-precision tradeoff across the entire memory device.
Solution Approach 2:
The sense amplifier array is segmented into precision-critical regions using long body transistors and area-efficient regions using short body transistors. This spatial segmentation allows the memory device to achieve overall area reduction while maintaining sufficient reference current precision in the regions where it matters most for accurate data read operations.
Data Source
AI summary
Methods of operating memory devices, generating reference currents in memory devices, and sensing data states of memory cells in a memory device are disclosed. One such method includes generating reference currents utilized in sense amplifier circuitry to manage leakage currents while performing a sense operation within a memory device. Another such method activates one of two serially coupled transistors along with activating and deactivating the second transistor serially coupled with the first transistor thereby regulating a current through both serially coupled transistors and establishing a particular reference current.