Word Line Underdrive Switching to Cut Memory Settling Time
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The time taken to change the voltage of the word line during the underdrive operation in memory devices affects the effectiveness of the underdrive operation, which is crucial for improving the setting of the word line.
Innovation Solution
A memory device with a first and second voltage regulator and a control logic that generates and applies an underdrive voltage to the selected word line before the operating voltage, using a well voltage regulator to set the well voltage to a negative level during the underdrive period, thereby reducing the settling time and improving the underdrive operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage of the word line is changed during the underdrive operation, then the setting of the word line is improved, but the settling time increases
Solution Approach 1:
The patent applies preliminary action by pre-charging the word line to a specific voltage level (e.g., half of the operating voltage) before the actual underdrive operation. This preliminary voltage preparation reduces the voltage transition time required during the underdrive phase, thereby decreasing the overall settling time while maintaining effective word line setting. The preliminary action prepares the electrical state of the word line in advance, minimizing the time needed for voltage stabilization.
2Reliability
If the underdrive voltage is applied to improve word line setting, then the memory device performance is enhanced, but the device complexity increases
Solution Approach 1:
The patent implements universality by designing the voltage regulator to perform multiple functions: it generates both the main operating voltage for the word line and the specific underdrive voltage levels required for optimized memory operations. This multi-functional approach eliminates the need for separate voltage generation circuits, thereby reducing overall device complexity while maintaining enhanced performance through proper underdrive voltage application.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the voltage output of the regulator based on operational requirements. The regulator can switch between different voltage levels (operating voltage and underdrive voltage) to optimize memory cell access and retention. This parameter adjustment capability allows the system to achieve enhanced performance without adding complex hardware, as the same circuit adapts its electrical parameters to different operational modes.
Data Source
AI summary
A memory device including a memory cell array having memory cells connected to a selected word line, a first voltage regulator configured to generate an underdrive voltage lower than an operating voltage, an address decoder including transistors, and configured to apply, to the selected word line, a voltage received during an underdrive period, a second voltage regulator configured to generate a well voltage to be applied to the transistors, a voltage transfer circuit configured to transfer the underdrive voltage or the well voltage to the address decoder, and a control logic configured, in response to the underdrive voltage being at a negative level, to control the second voltage regulator to set the well voltage to the negative level before the underdrive period, and to control the voltage transfer circuit to transfer the well voltage set to the negative level to the address decoder during the underdrive period.