Program Pulse Generator for Memory Array Capacitive Coupling
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Solution Overview
Problem
In conventional memory devices, capacitive coupling between word lines and bit line selectors can cause unintended programming of memory locations due to leakage currents, leading to data corruption, as the high impedance of selectors allows unselected memory strings to float and become conductive.
Innovation Solution
A program pulse generator is designed to minimize coupling between word lines and selector gates by generating program signals with a transient state based on the coupling characteristic, using a signal generator circuit and a reference load with controlled impedance to maintain selector states and prevent leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bit line selectors are kept off to ensure channel boosting, then unselected memory strings can float to prevent inadvertent programming, but capacitive coupling between word lines and selector gates can cause selectors to become conductive, resulting in leakage current and data corruption
Solution Approach 1:
The patent applies preliminary action by pre-charging the bit line selectors to a specific voltage level before word line programming occurs. This preliminary voltage state creates a voltage buffer that counteracts the capacitive coupling effect, preventing the selectors from becoming conductive during programming operations. The selector voltage is prepared in advance to be more negative than the coupled voltage from word lines, ensuring the selectors remain off despite capacitive interference.
Solution Approach 2:
The patent implements preliminary anti-action by applying a pre-charging voltage to the bit line selectors that is specifically designed to counteract the harmful capacitive coupling effect. This pre-applied voltage creates an opposing electrical condition that prevents the capacitive coupling from inducing unwanted conduction in the selectors, thereby protecting against leakage current before it can occur.
2Productivity
If program voltage is applied to word lines to program selected memory locations, then programming function is achieved, but capacitive coupling causes voltage to be induced in unselected memory strings, potentially causing inadvertent programming
Solution Approach 1:
The patent applies preliminary action by establishing the bit line selector voltage state before the word line programming pulse is applied. This pre-established voltage condition on the selectors creates an electrical barrier that prevents the programming voltage from coupling capacitively into unselected memory strings, thereby enabling fast programming while preventing inadvertent programming of unselected locations.
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 solution effectively reduces capacitive coupling, ensuring that selector states remain unchanged during programming, thereby preventing unintended programming and data corruption in memory devices.
Implementation Method 1
capacitive coupling of the world line voltages
Data Source
AI summary
A signal generator circuit is configured to generate program signals for a memory array. The program signals are applied to word lines in the memory array, and have a transient state based on a coupling characteristic of the word lines and selector gates. The transient state is configured to minimize coupling between the word lines and the gates of the selectors so that a state of each selector remains unchanged during the transient state.