Memory Cell Programming Current Control via Feedback Termination
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Solution Overview
Problem
Existing methods for programming non-volatile memory cells face inefficiencies in controlling current, leading to excessive programming time and power consumption, especially in multi-level data storage where precise current control is crucial.
Innovation Solution
The implementation of improved circuitry and methods that isolate memory cells during the precharge phase and ensure controlled programming using a program current, preventing damage from high precharge energy and allowing precise control over the programming process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a long programming pulse is applied to guarantee every memory cell is programmed, then programming reliability is improved, but programming time and power consumption increase excessively
Solution Approach 1:
The patent implements a feedback mechanism where a detection circuit monitors the programming state of the memory cell during the programming pulse. When the detection circuit determines the memory cell has reached the programmed state, it generates a signal to terminate the programming pulse early. This feedback-based early termination approach ensures reliable programming while avoiding excessive programming time and power consumption associated with always using the maximum programming pulse duration.
2Reliability
If a long programming pulse is applied to guarantee every memory cell is programmed, then programming reliability is improved, but power consumption increases excessively
Solution Approach 1:
The feedback mechanism with the detection circuit allows the system to stop programming as soon as the memory cell reaches the programmed state, thereby reducing total energy consumption while maintaining programming reliability. Without feedback, the system would continuously apply maximum power until the fixed programming pulse ends, wasting energy on already-programmed cells.
Solution Approach 2:
The patent applies programming pulses that may be shorter than the maximum guaranteed duration (partial action), terminated early based on detection feedback. This partial programming action is sufficient for most cells while avoiding the excessive energy consumption of always applying the full maximum pulse duration.
3Loss of time
If short high-voltage programming pulses are used with reading pulses to determine programmed state, then programming time is reduced, but time and power overhead from switching between program and read voltages increases
Solution Approach 1:
The patent merges the programming detection function into the existing programming circuitry by using the same word line and bit line signals during the programming phase to detect the programmed state. This eliminates the need for separate read voltage switching and reading pulse operations, thereby reducing voltage switching complexity and overhead while maintaining the ability to determine if programming is complete.
4Loss of time
If short programming pulses are used, then programming time is reduced, but energy efficiency decreases
Solution Approach 1:
The feedback mechanism ensures that programming pulses are terminated as soon as the memory cell reaches the programmed state, preventing unnecessary energy consumption from overly long pulses. This feedback-based termination optimizes energy efficiency by applying power only for the minimum necessary duration to achieve programming, rather than using fixed short pulses that may be insufficient or excessively long.
Data Source
AI summary
Improved circuitry and methods for programming memory cells of a memory device are disclosed. The improved circuitry and methods operate to isolate the memory cells from potentially damaging electrical energy that can be imposed during a precharge phase that precedes programming of the memory cells. Additionally, the improved circuitry and methods can operate to ensure that programming of the memory cells is performed in a controlled manner using only a program current. The improved circuitry and methods are particularly useful for programming non-volatile memory cells. In one embodiment, the memory device pertains to a semiconductor memory product, such as a semiconductor memory chip or a portable memory card.