Resistive Memory Sensing Circuit Using Pull-Up and Pull-Down Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing resistive memory devices face challenges in achieving reliable data sensing while being miniaturized, due to restrictions on reading conditions and increased memory cell array size.
Innovation Solution
A resistive memory device with a sensing circuit that generates pull-up and pull-down signals based on read currents flowing through the memory cell, using current mirror circuits to determine stored data, and a method that includes a regulating transistor and resistors to manage voltage levels, allowing for reliable data reading without the need for reference memory cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reference memory cells are used for data sensing, then sensing reliability is improved, but device size increases
Solution Approach 1:
The patent extracts and eliminates the reference memory cell component from the sensing circuit. Instead of using separate reference memory cells to establish voltage levels, the invention uses the bit line itself as the reference by generating pull-up and pull-down signals that compare against each other, thereby removing the need for additional reference cells and reducing device area.
Solution Approach 2:
The bit line serves multiple functions: it acts as both the signal carrier for data reading and the reference for comparison. The sensing circuit uses the bit line voltage as the reference point while simultaneously reading the memory cell data, eliminating the need for dedicated reference memory cells and reducing overall device complexity.
2Reliability
If memory cell array size is increased to accommodate reading conditions, then sensing reliability is improved, but device miniaturization is hindered
Solution Approach 1:
The patent transitions from a spatial approach (adding reference memory cells in the array) to a circuit-level approach (using voltage signal manipulation in the sensing circuit). By changing the dimension of the solution from physical array expansion to electrical signal processing, the invention maintains sensing reliability without increasing memory cell array size.
Solution Approach 2:
The invention changes the voltage parameters dynamically during the sensing operation. By adjusting voltage levels and generating complementary pull-up and pull-down signals, the circuit achieves reliable sensing without requiring additional physical space in the memory cell array, thus enabling device miniaturization.
3Ease of operation
If various read circuits are used to read memory cell data, then data reading capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the reference generation function and the data reading function into a single sensing circuit operation. By combining these functions and using the bit line as a common reference, the invention simplifies the overall reading circuit architecture while maintaining data reading capability, thereby reducing device complexity.
Solution Approach 2:
The sensing circuit uses itself to generate the reference voltage levels through the pull-up and pull-down signal generation. The circuit autonomously establishes its own reference points without requiring external reference memory cells or additional control circuits, thereby reducing overall system complexity while maintaining reading capability.
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
This approach improves sensing reliability and miniaturizes the memory device by eliminating the need for reference memory cells, resulting in a smaller device size and enhanced data reading capabilities.
Implementation Method 1
A random access memory (RAM) may include a volatile memory and a nonvolatile memory. The volatile memory may lose information stored therein each time power is removed, whereas the nonvolatile memory may retain data stored therein even when power is removed from the memory. The nonvolatile memory may include a resistive memory that stores data according to a resistance change of a memory cell.
Data Source
AI summary
A resistive memory device includes a resistive memory cell, a source line connected to one end of the resistive memory cell, a bit line connected to another end of the resistive memory cell, and a sensing circuit connected to the source line and the bit line. The sensing circuit is configured to generate a pull-up signal that is pulled up from a first voltage level to a second voltage level, based on a read current flowing through the resistive memory cell, generate a pull-down signal that is pulled down from a third voltage level to a fourth voltage level, based on the read current, and determine data that is stored in the resistive memory cell, based on a difference between the generated pull-up signal and the generated pull-down signal.