Ferroelectric Memory Read Circuit Using Feedback Capacitor Gain
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Solution Overview
Problem
Ferroelectric memory cell reading circuits face challenges due to the high cost and fabrication difficulties of operational amplifiers, particularly in low-cost and large-area electronic technologies like solution-processed thin film transistors, which result in high variability, low yield, and unsuitable charge amplification.
Innovation Solution
A memory circuit with a ferroelectric memory cell, a word line, a bit line, an input transistor, a gain element with a feedback capacitor, and an output terminal, utilizing a low gain amplification method with a gain of less than three, and an output latch to read and store memory states, allowing for simpler and cost-effective implementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an operational amplifier is used to amplify charge from the ferroelectric memory cell, then measurement precision is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent extracts the essential amplification function from a complex operational amplifier and implements it using a simplified circuit consisting of a capacitor and a switch. This extraction maintains the necessary charge amplification capability while eliminating the complexity and cost associated with traditional operational amplifiers, directly resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent replaces expensive, complex operational amplifiers with a simple, inexpensive capacitor-switch circuit. This substitution uses readily available, low-cost components that can be easily fabricated, thereby reducing manufacturing cost and device complexity while preserving the essential charge amplification function needed for precise measurement.
2Measurement precision
If an operational amplifier is used for charge amplification, then measurement precision is improved, but ease of manufacture deteriorates due to fabrication difficulties in low-cost technologies
Solution Approach 1:
The patent extracts the essential amplification function from a complex operational amplifier and implements it using a simplified circuit consisting of a capacitor and a switch. This extraction maintains the necessary charge amplification capability while eliminating the complexity and cost associated with traditional operational amplifiers, directly resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent replaces expensive, complex operational amplifiers with a simple, inexpensive capacitor-switch circuit. This substitution uses readily available, low-cost components that can be easily fabricated, thereby reducing manufacturing cost and device complexity while preserving the essential charge amplification function needed for precise measurement.
3Ease of manufacture
If solution-processed thin film transistors are used, then manufacturing cost is reduced, but reliability deteriorates due to high variability and low yield
Solution Approach 1:
The patent extracts the essential amplification function from a complex operational amplifier and implements it using a simplified circuit consisting of a capacitor and a switch. This extraction maintains the necessary charge amplification capability while eliminating the complexity and cost associated with traditional operational amplifiers, directly resolving the contradiction between measurement precision and device complexity.
4Ease of manufacture
If solution-processed thin film transistors are used, then manufacturing cost is reduced, but measurement precision deteriorates due to high offset and gain mismatches
Solution Approach 1:
The patent extracts the essential amplification function from a complex operational amplifier and implements it using a simplified circuit consisting of a capacitor and a switch. This extraction maintains the necessary charge amplification capability while eliminating the complexity and cost associated with traditional operational amplifiers, directly resolving the contradiction between measurement precision and device complexity.
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
The solution enables accurate and cost-effective reading of ferroelectric memory cells in low-cost technologies, reducing the risk of damage from extended bias application and charge leakage, while maintaining the integrity of memory states.
Implementation Method 1
a feedback capacitor, and an output terminal
Implementation Method 2
FE materials have remanent polarization after application and removal of an electric field that allows them to function as non-volatile memory cells
Data Source
AI summary
A memory circuit has a ferroelectric memory cell having a word line and a bit line, an input transistor connected to the bit line, a gain element electrically connected the bit line, wherein the gain element includes a feedback capacitor, and an output terminal. A method of reading a memory cell includes applying a voltage to a word line of the memory cell, causing charge to transfer from the memory cell to a feedback capacitor, generating a voltage, amplifying the voltage by applying a gain having a magnitude of less than three, sensing an output voltage at an output node to determine a state of the memory cell, and storing the memory state in a latch.