Memory Precharge Circuits for Parasitic Capacitance Reduction
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Solution Overview
Problem
Integrated circuit memory devices face slowed reading speeds due to capacitive coupling effects between closely placed data lines, leading to signal transition delays and increased charging times.
Innovation Solution
Incorporating precharge circuits that apply a precharge voltage to output data lines before sense amplifiers drive data signals, synchronized with sensing operations to minimize parasitic capacitance effects and reduce timing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If data lines are placed closely together to save layout area, then area utilization is improved, but reading speed deteriorates due to capacitive coupling effects
Solution Approach 1:
The patent applies precharge circuits to precharge the output data lines before the sense amplifiers drive the data signals. This preliminary action prepares the data lines by setting their initial voltage state, which reduces the charge required during subsequent data transitions and mitigates the capacitive coupling effects caused by closely placed data lines, thereby maintaining fast reading speed while preserving area efficiency
2Speed
If precharge circuits are added to reduce capacitive coupling effects, then reading speed is improved, but device complexity increases
Solution Approach 1:
The precharge circuits are integrated into the existing memory device architecture and share control signals with the sense amplifiers. The same control signal that enables sense amplifiers also controls the precharge circuits, allowing these additional components to be managed through existing control logic without requiring separate complex control mechanisms, thus limiting the increase in 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
This approach reduces the charge required to drive output data lines to different voltage levels, thereby enhancing reading speed and minimizing the impact of parasitic capacitance on data transfer timing.
Implementation Method 1
the capacitive coupling effect between the data lines degrades the signal transition time and slows down the reading speed because of the delay from the output of the sense amplifiers to the output circuits
Data Source
AI summary
A memory device includes a plurality of sense amplifiers coupled with an array of memory cells, a plurality of output data lines receiving outputs of corresponding sense amplifiers, and a plurality of precharge circuits configured to apply a precharge voltage on the output data lines. A controller provides control signals to the sense amplifiers and to the precharge circuits, including to cause the precharge circuits to precharge the output data lines before the sense amplifiers drive output data signals to the output data lines. The plurality of sense amplifiers includes banks of sense amplifiers, and each bank includes a sense amplifier having an output driving each output data line. The memory device includes data output multiplexers having inputs coupled to the output data lines, and the precharge circuits are coupled to the output data lines between outputs of the sense amplifiers and the data output multiplexers.