Bit Line Pre-Charge Slew Control for Memory Voltage Coupling
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Solution Overview
Problem
Semiconductor memory devices face issues with voltage coupling effects due to capacitive coupling, leading to errors in read and write operations, and increased power consumption when maintaining minimum voltage levels for faster operations.
Innovation Solution
A system and method for controlling the ramp-up speed of pre-charge voltage in bit lines using a voltage driving circuit with a current bias generating unit and a voltage driving unit, allowing for varying slew rates based on operation modes to mitigate voltage increases and coupling effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If minimum voltage levels are maintained on bit lines to speed up memory operations, then operation speed is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic pre-charging of bit lines only when needed for upcoming read operations, rather than continuously maintaining minimum voltage levels. The control circuit monitors operation schedules and activates pre-charging selectively, converting continuous power consumption into periodic action that occurs only when required for fast operation.
Solution Approach 2:
The patent dynamically adjusts the pre-charge voltage level and timing parameters based on the specific operation mode and timing requirements. By changing voltage parameters only when needed and at appropriate times, the system achieves fast operation speed without the continuous power penalty of maintaining fixed minimum voltage levels.
2Speed
If fast voltage transitions are used for pre-charging bit lines, then operation speed is improved, but voltage coupling errors increase due to capacitive coupling
Solution Approach 1:
The patent performs preliminary assessment of operation requirements to determine when pre-charging is actually needed. By predicting upcoming read operations and preparing bit lines only in advance of those specific operations, the system avoids unnecessary fast voltage transitions that would cause coupling errors, while still maintaining speed when pre-charging is genuinely required.
Solution Approach 2:
The control circuit incorporates feedback mechanisms to monitor actual voltage levels and operation timing, adjusting pre-charge timing and magnitude to prevent excessive voltage transitions. This feedback control ensures that pre-charging occurs at optimal moments with appropriate voltage changes, balancing speed requirements against coupling error prevention.
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 reduces voltage coupling errors and power consumption by adjusting the pre-charge rate according to operational needs, ensuring accurate memory operations while optimizing power usage.
Implementation Method 1
Semiconductor memory devices face issues with voltage coupling effects due to capacitive coupling
Data Source
AI summary
A voltage driving circuit comprises a current bias generating unit and a voltage driving unit. The current bias generating unit is configured to receive a mode signal and to generate a mode selection current in response to the mode signal. The voltage driving unit is coupled to the current bias generating unit, and is configured to receive the mode selection current and to drive an output voltage at a slew rate that is set according to the mode selection current. The voltage driving unit can include a plurality of stages, where each stage is configured to drive the output voltage at a respective different slew rate according to the mode signal.