Page Buffer Pre-Charging for Nonvolatile Memory Sensing
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Solution Overview
Problem
Nonvolatile memory devices, such as flash memory devices, face challenges in data sensing due to varying transition speeds of control signals to target levels in page buffers, leading to differences in sensing characteristics and reliability issues during data retrieval.
Innovation Solution
A memory device with a page buffer that includes a pre-charge unit for pre-charging bit lines and sensing nodes, a bit line connection unit for controlling voltages based on control signals, and data input and output units for generating sensing data, allowing for synchronized voltage control and improved data sensing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control signals are applied to page buffers to sense voltage of sensing nodes, then data sensing operation is enabled, but transition time of control signals delays the sensing process
Solution Approach 1:
The patent applies preliminary action by pre-charging the bit line and sensing node to target voltage levels before the actual sensing operation begins. The pre-charge unit charges the bit line through a first pre-charge path and the sensing node through a second pre-charge path, ensuring that when control signals are subsequently applied, the sensing operation can proceed without waiting for voltage stabilization, thus reducing sensing time while maintaining reliability
2Productivity
If control signals are transitioned to target levels, then data sensing can proceed, but varying transition speeds cause differences in sensing characteristics
Solution Approach 1:
The patent eliminates the need for control signal transition waiting by pre-charging the sensing node and bit line to their target levels in advance. Since the voltages are already stabilized before sensing begins, variations in control signal transition speeds among different page buffers no longer affect sensing characteristic consistency, thereby improving both productivity and reliability simultaneously
Solution Approach 2:
The patent extracts the voltage stabilization requirement from the sensing operation by separately performing pre-charging before sensing. The pre-charge unit independently charges the bit line and sensing node to target levels, removing the dependency on control signal transition timing and ensuring uniform sensing characteristics across all page buffers regardless of their individual transition speeds
Data Source
AI summary
A page buffer includes a pre-charge unit for pre-charging a bit line of a selected memory cell of a memory cell array via a first pre-charge line and pre-charging a sensing node via a second pre-charge line, during a pre-charge time, a bit line connection unit connected between the bit line and the sensing node and including a connecting node connected to the first pre-charge line, the bit line connection unit controlling a voltage of the sensing node, during a develop time, based on a bit line connection control signal and a sensing node voltage control signal, and a data input and output unit for generating sensing data by sensing a level of the voltage of the sensing node, during a sensing time.