Flash Memory Voltage Generator Merging for Area Reduction
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Solution Overview
Problem
As the degree of integration in flash memory devices increases, the number of wordlines connected to a memory block grows, requiring various voltages to drive them, leading to increased area and power consumption.
Innovation Solution
A memory device with a voltage generating circuit that outputs different non-selection voltages to unselected wordlines through driving lines, floating them when they reach specific target levels, reducing the need for multiple voltage sources and generators, thereby minimizing area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple voltage generators are used to drive multiple wordlines, then the wordline driving capability is improved, but the area and power consumption increase
Solution Approach 1:
The patent merges multiple voltage generator functions into a single voltage generator that can output different non-selection voltages (e.g., first non-selection voltage VREAD1, second non-selection voltage VREAD2) through time-division or multiplexing. This single generator serves multiple wordline groups, reducing the total number of voltage generators from multiple to one, thereby significantly reducing the area occupied by voltage generator circuits while maintaining the capability to drive multiple wordlines with appropriate voltages.
Solution Approach 2:
The single voltage generator is designed with multi-functionality to serve multiple purposes: it can generate different voltage levels (first non-selection voltage, second non-selection voltage) for different wordline groups. This universal voltage generator replaces what would traditionally require multiple dedicated voltage generators, each specialized for specific wordlines, thus reducing area while maintaining comprehensive wordline driving capability.
2Adaptability or versatility
If multiple voltage generators are used to drive multiple wordlines, then the wordline driving capability is improved, but the power consumption increases
Solution Approach 1:
By merging multiple voltage generator functions into a single multi-functional voltage generator, the patent reduces the total power consumption. Fewer voltage generators mean fewer circuits that require power supply, and the single generator can be optimized for efficiency by only activating when needed to drive specific wordline groups, rather than having multiple generators continuously powered or activated simultaneously.
Solution Approach 2:
The voltage generator operates in a time-division or periodic manner, generating different non-selection voltages for different wordline groups at different times. This periodic operation allows the single voltage generator to serve multiple wordlines sequentially, reducing the overall power consumption compared to having multiple voltage generators operating simultaneously or continuously, while still achieving comprehensive wordline driving capability.
3Area of stationary object
If a single voltage generator is used for all wordlines, then the area is reduced, but the voltage control precision deteriorates
Solution Approach 1:
The single voltage generator is designed with dynamic voltage output capability, allowing it to adjust and generate different voltage levels (first non-selection voltage VREAD1, second non-selection voltage VREAD2) based on the specific wordline group being driven. This dynamic adaptation enables precise voltage control for different wordlines despite using a single generator, as the generator can modify its output characteristics to match the requirements of each wordline group, thereby maintaining voltage control precision while reducing area.
Solution Approach 2:
The voltage generator utilizes parameter changes in its output characteristics to serve different wordline groups. By changing voltage parameters (e.g., outputting first non-selection voltage for one group, second non-selection voltage for another), the single generator achieves precise voltage control for different wordlines. This parameter-based differentiation allows the generator to maintain the precision normally associated with multiple dedicated generators, while the area is reduced due to the single-generator architecture.
Data Source
AI summary
Disclosed is a memory device includes a memory block that is connected with a plurality of wordlines, a voltage generating circuit configured to output a first non-selection voltage through a plurality of driving lines, and an address decoding circuit configured to connect the plurality of driving lines with unselected wordlines of the plurality of wordlines. During a wordline setup period for the plurality of wordlines, the voltage generating circuit floats first driving lines corresponding to first unselected wordlines of the unselected wordlines from among the plurality of driving lines when the first unselected wordlines reach a first target level, and floats second driving lines corresponding to second unselected wordlines of the unselected wordlines from among the plurality of driving lines when the second unselected wordlines reach a second target level different from the first target level.