Dynamic Bit Line Charging Rate Control for Memory Programming
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Solution Overview
Problem
In non-volatile semiconductor memory devices, the charging of unselected bit lines during programming can result in high current consumption, leading to voltage drops and impaired device performance, requiring additional circuitry and increased costs for monitoring and adjusting the charging rate.
Innovation Solution
The rate at which unselected bit lines are charged is dynamically adjusted based on program conditions, such as the number of program loops completed or the completion status of a program state, allowing for faster charging during later stages of programming to enhance performance without the need for specialized circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unselected bit lines are charged to inhibit voltage during programming, then programming inhibition is achieved, but peak current consumption increases causing voltage drops
Solution Approach 1:
The patent applies dynamics by making the bit line charging rate variable rather than fixed. The charging rate is dynamically adjusted based on program conditions - using a first charging rate when programming is needed and a second (slower) charging rate when inhibition is needed. This resolves the contradiction by adapting the charging behavior to the specific operational context, achieving reliable inhibition only when necessary while minimizing current consumption during inhibition phases.
2Use of energy by moving object
If bit line charging rate is limited to reduce current, then voltage stability improves, but programming speed decreases
Solution Approach 1:
The patent changes the parameter of bit line charging rate based on program conditions. By switching between different charging rates (first rate for programming, second slower rate for inhibition), the system optimizes both voltage stability and programming speed. The charging rate parameter is adjusted to match the operational requirement, ensuring fast programming when needed while maintaining voltage stability during inhibition periods.
3Use of energy by moving object
If monitoring circuitry is added to detect bit line charging speed, then charging rate control improves, but device complexity and cost increase
Solution Approach 1:
The patent implements self-service by using the existing program condition information (which is already available in the programming logic) to control the bit line charging rate. The system uses its own internal state (program condition) to automatically adjust the charging behavior without requiring external monitoring circuits. This eliminates the need for additional complexity while maintaining effective charging rate control.
Data Source
AI summary
Methods and devices for charging unselected bit lines are disclosed. The rate at which inhibited (or unselected) bit lines are charged may depend on a program condition. The program condition may be completion of a program loop. As another example, the program condition may be a certain program state completing or nearly completing programming. As one example, the bit lines may be charged at a faster rate prior to the program condition occurring than after the program condition. As another example, the bit lines may be charged at a slower rate prior to the program condition than after the program condition. Charging the unselected bit lines at a slower rate may reduce current consumption. Charging the unselected bit lines at a faster rate may allow for faster programming.