Memory Device EMI Reduction via Asymmetric Control Signal Routing
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Solution Overview
Problem
Existing USB memory devices face challenges in minimizing electromagnetic interference (EMI) due to higher frequency control signals, which can be exacerbated by longer wire lengths for control signals, especially in high-speed data transfer protocols like USB3.0.
Innovation Solution
A memory device configuration that includes a controller and non-volatile memory with a periodic control signal sent from a terminal on the controller to the non-volatile memory, reducing wire length for control signals and employing symmetric and equalized transmission paths for differential signals to mitigate EMI, while supporting high-speed data rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher frequency control signals are used for high-speed data transfer, then data rate is improved, but electromagnetic interference increases
Solution Approach 1:
The patent applies asymmetry by implementing different wire length configurations for control signals versus differential data signals. Specifically, control signal wires are minimized in length and routed directly from the USB controller to the NAND memory, while differential signal paths maintain symmetry. This asymmetric approach prioritizes minimizing EMI generation at the control signal level while preserving high-speed data transfer capability.
Solution Approach 2:
The patent segments the signal transmission paths into distinct categories: control signal paths and differential data signal paths. Each segment is optimized independently - control signals use minimized wire lengths with direct routing, while differential signals use balanced symmetric paths. This segmentation allows targeted EMI mitigation for control signals without compromising overall system performance.
2Object-generated harmful factors
If wire length for control signals is reduced, then electromagnetic interference is suppressed, but device complexity increases
Solution Approach 1:
The patent merges the control signal transmission function directly into the existing USB controller-NAND memory interface structure. By integrating control signal routing within the same physical interface used for data transfer, the patent eliminates the need for separate dedicated control signal wires, thereby reducing overall wire length and EMI without adding significant routing complexity.
3Object-generated harmful factors
If symmetric transmission paths are used for differential signals, then electromagnetic interference is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements partial symmetry by ensuring that differential signal pairs maintain equal wire lengths only where necessary for EMI cancellation, rather than enforcing symmetry across the entire signal path. This partial application of symmetry reduces the manufacturing precision burden while still achieving the critical EMI mitigation benefit in the most sensitive signal transmission segments.
Data Source
AI summary
According to one embodiment, a memory controller sends a periodic control signal from a first terminal on a non-volatile memory side to the non-volatile memory, and the control signal includes a data strobe signal, a write enable signal, and a read enable signal.