SRAM Access Unit Asymmetric Voltage Write Margin
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional SRAM access units experience failed write operations when the supply voltage is low, making it difficult to successfully alter data stored in the memory.
Innovation Solution
The access unit employs two inverters with different variable voltages supplied through the bitlines, causing a voltage and current imbalance between them, which increases the write margin and allows successful data writing even at low SRAM supply voltages by reducing the charging current output from MOS transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the supply voltage is reduced to lower power consumption, then power consumption is reduced, but write operations fail due to insufficient voltage margin
Solution Approach 1:
The patent applies asymmetry by providing different variable voltages to the first and second inverters through separate bitlines. The first inverter receives a first variable voltage while the second inverter receives a second variable voltage, creating an asymmetric voltage distribution that generates current imbalance. This asymmetry enables successful write operations at low supply voltages by ensuring sufficient current difference between the cross-coupled inverters, thereby resolving the contradiction between low power consumption and write operation reliability.
2Use of energy by moving object
If the supply voltage is reduced, then power consumption is reduced, but the write margin becomes smaller making write operations harder
Solution Approach 1:
The patent creates asymmetric voltage conditions by supplying different variable voltages to the two inverters through separate bitlines. This asymmetry generates a current imbalance that directly increases the write margin, making write operations easier even at low supply voltages. The first bitline provides a first variable voltage while the second bitline provides a second variable voltage, ensuring sufficient current difference to achieve large write margin under low power consumption conditions.
Solution Approach 2:
The patent dynamically changes the voltage parameters supplied to the inverters through variable voltages on the bitlines. By adjusting the first variable voltage and second variable voltage independently, the system optimizes the current imbalance to maintain large write margin. This parameter change approach allows the write margin to be maintained at low supply voltages, resolving the contradiction between power consumption and ease of write operation.
3Use of energy by moving object
If conventional SRAM access units are used with low supply voltage, then power consumption is reduced, but data writing fails due to delayed flip point
Solution Approach 1:
The patent applies asymmetry by providing different variable voltages to the first and second inverters, which creates current imbalance that accelerates the flip point occurrence. The first inverter receives a first variable voltage while the second inverter receives a second variable voltage, ensuring that the flip point occurs promptly even at low supply voltages. This asymmetric voltage supply prevents delayed flip point and ensures accurate data writing under low power consumption conditions.
Data Source
AI summary
An access unit for a static random access memory (SRAM) is provided. The access unit comprises two inverters. Two different variable voltages are supplied to the two inverters via bitlines to cause an imbalance in the current strengths between the two inverters so that data can be written on the SRAM.