Two-Rail Level Shifting for Thin-Oxide Memory High-Voltage Bias
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Solution Overview
Problem
Existing memory systems face challenges in providing high voltage to memory devices with thinner gate oxide thicknesses, as they can only handle low voltage, and high voltage operations stress these devices, leading to potential damage and increased costs when using additional devices for mitigation.
Innovation Solution
The implementation of a two-rail level shifting circuit that receives a low voltage input and modifies it to generate higher output voltages, using extended drain devices to reduce electric field stress across the gate oxide, allowing for safe high voltage operations without the need for thicker gate oxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If memory devices with thinner gate oxide thicknesses are used to reduce device size, then device scaling is improved, but the devices can only handle low voltage and high voltage operations cause stress and potential damage
Solution Approach 1:
A level shifting circuit is introduced as an intermediary between the control logic and the memory device. This circuit translates low-voltage control signals into appropriate high-voltage signals for the memory device, allowing the memory device to operate at high voltage while being controlled by low-voltage logic. The level shifting circuit acts as a buffer that protects the thin gate oxide memory device by providing controlled voltage transitions and isolation.
Solution Approach 2:
The patent changes the voltage parameters dynamically based on operational requirements. The level shifting circuit adjusts output voltage levels according to the operational mode (read, program, erase) of the memory device. During read operations, low voltage is maintained, while during program and erase operations, high voltage is supplied to the memory device through the level shifting circuit, optimizing both device scaling and reliability.
2Reliability
If additional devices are employed to mitigate stress on thin gate oxide devices during high voltage operations, then device protection is improved, but manufacturing cost and circuit complexity increase
Solution Approach 1:
The level shifting circuit is designed to perform multiple functions: voltage translation, signal buffering, and operational control. It can interface with different memory device types (NAND, NOR) and support various operations (read, program, erase) by dynamically adjusting its output voltage levels. This multi-functional design eliminates the need for separate protection circuits for each operation, reducing overall circuit complexity while maintaining comprehensive device protection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the provision of high voltage to memory devices with thinner gate oxides, reducing stress and potential damage, while maintaining cost-effectiveness and simplifying circuit fabrication by avoiding the use of thicker gate oxides.
Implementation Method 1
a two-rail level shifting circuit configured to receive a low voltage input and modify the low voltage input to generate one or more output signals
Implementation Method 2
using extended drain devices to reduce electric field stress across the gate oxide
Data Source
AI summary
Apparatus, systems, and methods for providing high voltage to memory devices are provided. One apparatus includes a low voltage input and a two-rail level shifting. The two-rail level shifting is configured to increase the low voltage or to decrease the low voltage to an amount that is less than or equal to a ground potential based on the amount of the low voltage. A system includes a low voltage input for receiving a voltage and a two-rail level shifting coupled to the low voltage input. The two-rail level shifting is configured to increase the voltage to a positive voltage if the voltage is equal to a ground potential and decrease the voltage to a negative voltage if the voltage is greater than the ground potential. One method includes receiving a voltage, modifying the voltage to generate one of a plurality of output voltages, and providing the output voltage to a memory device.