Memory Device Program Loop Optimization via Conditional Current Sensing
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Solution Overview
Problem
Current memory devices require lengthy program operations due to the need for current sensing checks in every program loop, which increases operating time, especially when the number of memory cells reaching a target voltage is below a reference number.
Innovation Solution
Implementing a method where current sensing checks are skipped in program loops until the number of memory cells with threshold voltages at or above a target voltage reaches a reference number, thereby optimizing the program operation by only performing checks when a predetermined threshold is met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current sensing check operation is performed in every program loop, then reliability of program operation is improved, but operating time increases
Solution Approach 1:
The patent applies partial action by performing current sensing check operations selectively rather than in every program loop. Specifically, the check is performed only when the number of memory cells reaching the target voltage is greater than or equal to a reference number, skipping unnecessary checks in early loops where few cells have reached the target voltage. This reduces the total number of sensing operations while maintaining program reliability.
Solution Approach 2:
The patent changes the parameter of sensing operation frequency from constant (every loop) to variable (conditional based on cell count). By monitoring the number of memory cells that have reached the target voltage and comparing it against a reference number, the system dynamically adjusts whether to perform the current sensing check, thereby optimizing the balance between reliability and speed.
2Loss of time
If current sensing check operation is skipped in early program loops, then operating time is reduced, but program operation reliability may deteriorate
Solution Approach 1:
The patent changes the parameter of sensing operation frequency from constant (every loop) to variable (conditional based on cell count). By monitoring the number of memory cells that have reached the target voltage and comparing it against a reference number, the system dynamically adjusts whether to perform the current sensing check, thereby optimizing the balance between reliability and speed.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the number of memory cells reaching the target voltage and using this information to decide whether to perform the current sensing check. The reference number serves as a threshold that triggers the sensing operation only when sufficient cells have been programmed, ensuring reliability while avoiding premature checks.
Data Source
AI summary
A memory device and a method of operating the same are provided. The memory device may include a peripheral circuit configured to perform a plurality of program loops and program a page selected from among the plurality of pages, wherein the peripheral circuit may count a number of memory cells whose threshold voltages have increased up to a first target voltage, among a part of memory cells included in the selected page, and may perform a current sensing check operation of determining whether a verify operation performed in a previous program loop has passed or failed, and a control logic circuit configured to control the peripheral circuit so that the current sensing check operation is performed when the number of memory cells whose threshold voltages have increased up to the first target voltage, is equal to or greater than a reference number of memory cells.