3D Reference Memory Circuit for PVT-Tracked Sense Amplifier Margins
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Solution Overview
Problem
High voltage sensing circuits are required for reliable operation in high density memory due to variations in process, voltage, and temperature (PVT) conditions, which are incompatible with modern memory technologies, and bandgap reference circuits are not immune to these variations.
Innovation Solution
A memory device with a data memory and a reference memory that generates a reference signal to track PVT conditions, using conversion circuitry to produce a reference signal for sense amplifiers, and includes a reference memory with matching 3D structures to improve sensing margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high voltage sensing circuits are used to ensure reliable operation under PVT variations, then sensing reliability is improved, but device compatibility with modern memory technologies deteriorates
Solution Approach 1:
The patent changes the voltage parameter by introducing a reference memory that generates a reference voltage dynamically tracking PVT conditions. This allows the sensing circuit to operate at lower voltages while maintaining reliability, as the reference voltage adapts to compensate for PVT variations instead of requiring fixed high voltage operation
Solution Approach 2:
The patent creates a copy of the memory structure (reference memory) that replicates the PVT characteristics of the data memory. This reference copy generates a corresponding reference voltage that mirrors the PVT variations, enabling the sensing circuit to compensate for variations without requiring high voltage operation
2Stability of the object's composition
If bandgap reference circuits are used to generate reference voltage, then reference voltage stability is improved, but immunity to PVT variations deteriorates
Solution Approach 1:
Instead of using a traditional bandgap reference, the patent creates a copy of the memory structure (reference memory) that replicates the actual PVT characteristics of the data memory. This reference copy generates a reference voltage that dynamically tracks PVT variations, providing both stability and adaptability to PVT conditions
Solution Approach 2:
The reference memory structure provides implicit feedback by generating a reference voltage that automatically adjusts to PVT conditions. The reference voltage responds to PVT variations in the same manner as the data memory, creating a self-adjusting system that maintains sensing accuracy under varying conditions
Data Source
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AI summary
A memory device includes a 3D data memory and a 3D reference memory. The reference memory is used to generate a reference signal used to sense data in the data memory. Conversion circuitry converts signals from a group of memory cells in the reference memory into a reference signal. The reference signal is applied to a sense amplifier to sense data stored in a selected memory cell in the data memory.