PIM Memory Cell Switching for Stable Product-Sum Operations
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Solution Overview
Problem
Existing semiconductor devices using Processing in Memory (PIM) for product-sum operations face instability due to variations in memory cell characteristics such as current and capacity, which affect the stability of sum operations.
Innovation Solution
A semiconductor device with a configuration that includes first and second data lines and memory cells connected to these lines, utilizing switches and data holding circuits to control characteristic values, reducing variations by optimizing current paths and performing product-sum operations with three-valued logic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of memory cells connected to the data line increases to perform more product-sum operations, then the processing capability is improved, but the stability of sum operations deteriorates due to variations in characteristic values such as current and capacity
Solution Approach 1:
The patent changes the characteristic values of memory cells by controlling switches connected to data lines based on values held in data holding circuits. This allows dynamic adjustment of current and capacity parameters to compensate for variations, thereby maintaining stable sum operations even when many memory cells are connected to the data line.
2Reliability
If switches and data holding circuits are added to control characteristic values, then the stability of operations is improved, but the device complexity increases
Solution Approach 1:
The data holding circuits serve multiple functions: they store data values and simultaneously control the characteristic values of memory cells by actuating switches. This multi-functionality reduces the need for separate control circuits, thereby limiting the increase in device complexity while improving operational stability.
3Reliability
If characteristic values are controlled through additional switches and circuits, then variations in memory cell characteristics are reduced, but the power consumption increases
Solution Approach 1:
The system uses the data values already stored in the data holding circuits to control the characteristic values of memory cells. This self-service approach eliminates the need for additional external control signals or separate control circuits, thereby reducing power consumption while still achieving variation reduction in memory cell characteristics.
Data Source
AI summary
A semiconductor device includes a first data line, a second data line, and a memory cell connected to the first data line and the second data line. The memory cell includes a plurality of switches, a first data holding circuit, a second data holding circuit, a third data holding circuit, a fourth data holding circuit, and an input line. A characteristic value of the memory cell is changeable by controlling the switch connected to the first data line among the plurality of switches based on a value held by the third data holding circuit and by controlling the switch connected to the second data line among the plurality of switches based on a value held by the fourth data holding circuit.