RRAM Crossbar Row Driver Feedback for Switch Resistance Error
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Solution Overview
Problem
RRAM-based crossbar array circuits face significant row switch resistance errors, particularly in high-current environments, which impact resolution and accuracy during operations, and increasing switch size to reduce this error leads to increased silicon area, manufacturing costs, and parasitic R/C issues.
Innovation Solution
The implementation of a row driver circuit using negative feedback provided by an operational amplifier (Op-amp) within the crossbar array circuit, which reduces the effective on-resistance of the switch without increasing the switch size, thereby minimizing error terms and enhancing RRAM resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the switch size is increased to reduce row switch resistance error, then the resistance error is reduced, but the silicon area increases and parasitic R/C issues worsen
Solution Approach 1:
The patent applies negative feedback through an operational amplifier to sense the voltage drop across the row switch and generate a compensating signal. The Op-amp continuously monitors the switch resistance error and adjusts the output to cancel out the resistance effect, achieving precise compensation without increasing switch size or silicon area.
Solution Approach 2:
The patent introduces an operational amplifier as an intermediary component between the row switch and the crossbar array. This intermediary device senses the resistance error and provides compensation signals, enabling precise resistance error reduction without directly modifying the switch dimensions or increasing silicon footprint.
2Measurement precision
If the switch size is increased to reduce row switch resistance error, then the resistance error is reduced, but manufacturing costs increase
Solution Approach 1:
The negative feedback mechanism using an operational amplifier provides precise resistance error compensation through electronic control rather than physical switch size increase. This approach maintains standard manufacturing processes while achieving high precision, avoiding the increased manufacturing costs associated with larger switches.
3Measurement precision
If the switch size is increased to reduce row switch resistance error, then the resistance error is reduced, but parasitic R/C issues increase
Solution Approach 1:
The operational amplifier with negative feedback compensates for resistance errors electronically without requiring larger switch dimensions. By sensing and canceling resistance effects through feedback control, the solution achieves precise compensation while avoiding increased parasitic capacitance and resistance that would result from larger switch sizes.
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 significantly reduces the error terms associated with switch resistance, improving RRAM resolution and accuracy, especially in AI and neural network applications, while maintaining low power consumption and avoiding the adverse effects of larger switch sizes.
Implementation Method 1
The implementation of a row driver circuit using negative feedback provided by an operational amplifier (Op-amp) within the crossbar array circuit, which reduces the effective on-resistance of the switch
Data Source
AI summary
Technologies relating to RRAM-based crossbar array circuits and more specifically to reducing row switch resistance error of in crossbar array circuits are disclosed. An example apparatus includes: a first Op-amp including a first inverting Op-amp input, a first non-inverting Op-amp input, and a first Op-amp output; a row switch device including a row switch input and a row switch output; a crossbar array including a row wire, a column wire, and a cross-point device connected between the row wire and the column wire. The row switch input is connected to the first Op-amp output; the row switch output is connected to the first inverting Op-amp input; and the row switch output is connected to the row wire.