Nonvolatile Memory Well Voltage Circuit for Leakage Reduction
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Solution Overview
Problem
Nonvolatile memory devices face slow access speeds due to low cell current as memory cell size is reduced, and existing solutions do not effectively manage current consumption in unselected memory blocks.
Innovation Solution
A circuit for supplying well voltages in nonvolatile memory devices, comprising an erase voltage supply unit, a discharge unit, and a negative voltage supply unit, which includes switches, controllers, and capacitors to manage and discharge voltages, reducing current consumption and leakage current in unselected memory blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cell size is reduced to increase integration, then storage capacity is improved, but access speed deteriorates due to low cell current
Solution Approach 1:
The patent applies local quality by providing different voltage conditions to different regions of the memory device. Specifically, a negative voltage is supplied to the well in unselected memory blocks to reduce leakage current, while normal voltage is maintained in selected blocks for proper operation. This localized voltage control enables high integration without compromising access speed in active cells.
2Use of energy by moving object
If negative voltage is supplied to well in unselected memory blocks, then current consumption is reduced, but device complexity increases due to additional voltage supply units and control circuits
Solution Approach 1:
The voltage supply unit is designed with multi-functionality to reduce device complexity. The same voltage supply unit can provide both normal operating voltage and negative voltage for leakage reduction, depending on the operation mode. The control unit intelligently switches between different voltage supply modes (erase voltage supply, negative voltage supply, or discharge mode) based on the current operation, allowing one circuit to perform multiple functions without requiring separate dedicated circuits for each function.
Solution Approach 2:
The patent employs dynamic voltage supply where the well voltage is changed based on operational requirements. During read/verify operations, negative voltage is dynamically supplied to unselected blocks to reduce leakage. During erase operations, erase voltage is supplied instead. The discharge unit dynamically discharges the well voltage when switching between operations. This dynamic adaptation allows the system to optimize current consumption without permanently increasing structural complexity.
3Manufacturing precision
If multiple voltage supply units are added to manage well voltages, then voltage control precision is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple voltage supply functions into a single integrated voltage supply unit. This unit can supply erase voltage, negative voltage, or discharge voltage to the well based on control signals, eliminating the need for separate dedicated circuits for each voltage type. The control unit coordinates the switching between different voltage modes, achieving precise voltage control while reducing overall device complexity through functional integration.
Data Source
AI summary
A circuit for supplying well voltages in a nonvolatile memory device includes an erase voltage supply unit for supplying an erase voltage to a well in response to an erase enable signal, a discharge unit for discharging the erase voltage, supplied to the well, in response to a discharge control signal, and a negative voltage supply unit for supplying a negative voltage to the well in response to a negative voltage output enable signal.