Memory Sub-system Controller Firmware for Dynamic Wordline Start Voltage
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Solution Overview
Problem
Current memory sub-systems face limitations in tracking a large number of open blocks due to the restriction of a single dynamic wordline start voltage (DWSLV) storage element per die, leading to inefficiencies in programming time and capacity constraints.
Innovation Solution
The dynamic wordline start voltage operation is shifted from the memory device level to the memory sub-system controller level, allowing for manual or semi-automatic configuration of firmware to determine the wordline start voltage, enabling tracking of hundreds or thousands of open blocks without increasing storage capacity at the memory device level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dynamic wordline start voltage operation is performed at the memory device level with a single storage element per die, then the memory device design remains simple, but the system cannot track a large number of open blocks and suffers from programming time inefficiency
Solution Approach 1:
The patent introduces a firmware layer at the memory sub-system controller level as an intermediary to manage dynamic wordline start voltage operations. This firmware maintains a record of open blocks and determines wordline start voltages, allowing the system to track hundreds or thousands of open blocks without adding storage elements to the memory device itself. The intermediary firmware layer resolves the contradiction by providing complex tracking capabilities while keeping the memory device design simple.
Solution Approach 2:
The patent shifts the DWSLV operation from the memory device level to the memory sub-system controller level, effectively moving the management function to another dimension of the system hierarchy. This dimensional shift allows the controller's firmware to handle the complexity of tracking multiple open blocks across hundreds or thousands of blocks, while the memory devices themselves remain relatively simple with unchanged design.
2Adaptability or versatility
If the number of open blocks to be tracked is increased, then the programming capacity and parallelism are improved, but the storage element restriction at the memory device level prevents effective management
Solution Approach 1:
The firmware at the controller level acts as an intermediary that maintains the record of open blocks and manages wordline start voltage assignments. This intermediary approach allows the system to track a large number of open blocks (hundreds or thousands) without requiring proportional increases in storage elements at the memory device level, as the firmware uses its own memory resources to maintain the block records.
Solution Approach 2:
The firmware-based management system provides universal functionality for tracking and managing multiple open blocks across different memory devices and planes. Rather than requiring dedicated storage elements in each memory device, the universal firmware layer can manage open blocks across the entire memory sub-system, enabling multi-plane parallel programming and efficient utilization of programming resources.
3Loss of time
If manual or semi-automatic firmware configuration is used to determine wordline start voltage, then the programming time is reduced and parallel programming is enabled, but the system complexity at the controller level increases
Solution Approach 1:
The firmware performs preliminary actions by maintaining a record of open blocks and pre-determining wordline start voltages before programming operations are executed. This preliminary management of voltage assignments and block tracking enables more efficient programming operations and allows for parallel programming across multiple planes, as the voltage management is prepared in advance rather than being determined dynamically during programming.
Data Source
AI summary
A request to perform a write operation at a memory device is received. Current wordline start voltage (WLSV) information associated with a particular memory segment of the plurality of memory segments is retrieved. In a firmware record in a memory sub-system controller, information is stored indicative of a last written memory page associated with the particular memory segment on which the write operation is performed. The firmware record is managed in view of the information indicative of the last written memory page associated with the performed write operation. Each entry of the firmware record comprises one or more identifying indicia associated with a respective memory segment, at least one of the identifying indicia being a wordline start voltage (WLSV) associated with the respective memory segment, and the other indicia is a plane mask. Plane mask compatibility helps identify which pages can be programmed together in a multi-plane write operation.