Memory Channel Signaling Mode Switching for NRZ and PAM4

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Solution Overview

Problem

Current signal modulation schemes, such as NRZ, struggle to meet the growing demand for higher-capacity data transmission at higher speeds, necessitating the development of alternative schemes like PAM4 for improved data transmission efficiency.

Innovation Solution

A memory device and system that dynamically select between NRZ and PAM4 transmission signaling modes based on detected mode parameters such as channel loss, current consumption, and termination voltage, using a mode detection circuit and dual-mode transceiver to optimize data transmission according to the channel environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If NRZ signaling mode is used, then device complexity is reduced and ease of operation is improved, but data transmission capacity and speed are limited

Engineering Contradiction:

Improvedata transmission capacityVSAvoidsignaling mode complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a dual-mode transceiver that can dynamically switch between NRZ and PAM4 signaling modes based on detected channel conditions. The mode detection circuit continuously monitors parameters such as channel loss, current consumption, and termination voltage, and automatically selects the optimal signaling mode, making the system adaptive rather than static.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the signaling mode parameter from a fixed state to a variable state that can be adjusted based on channel conditions. By detecting mode parameters and selecting between different signaling modes (NRZ or PAM4), the system optimizes data transmission capacity while managing the complexity through automated parameter selection.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If PAM4 signaling mode is used, then data transmission capacity and speed are improved, but channel loss increases and reliability decreases

Engineering Contradiction:

Improvedata transmission speedVSAvoiddata transmission reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the mode detection circuit continuously monitors channel conditions including channel loss, current consumption, and termination voltage. Based on this feedback, the system automatically selects the appropriate signaling mode (NRZ or PAM4) to maintain reliable data transmission while optimizing for speed when conditions permit.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the signaling mode based on real-time channel conditions. When channel loss is low and conditions are favorable, PAM4 mode is selected for higher speed transmission. When channel loss increases or conditions deteriorate, the system switches to NRZ mode to maintain reliability, thus adapting to changing conditions.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If automatic mode selection is implemented, then adaptability to channel environment is improved, but device complexity increases

Engineering Contradiction:

Improvechannel environment adaptabilityVSAvoidmode detection circuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent performs preliminary detection of mode parameters (channel loss, current consumption, termination voltage) during a training period before actual data transmission begins. This preliminary action allows the system to pre-select the optimal signaling mode, reducing the complexity of continuous monitoring during operation while maintaining high adaptability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The dual-mode transceiver is designed to perform multiple functions: it can operate in both NRZ and PAM4 signaling modes, and the mode detection circuit can detect multiple parameters (channel loss, current consumption, termination voltage). This multi-functionality is achieved through a unified architecture that handles both modes and detection tasks, reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Measurement precision

If training operation is performed to detect mode parameters, then transmission signaling mode selection accuracy is improved, but transmission time is increased

Engineering Contradiction:

Improvemode parameter detection accuracyVSAvoidtraining operation time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs a training operation during the initial period to detect mode parameters with high accuracy, but only once or occasionally rather than continuously. This partial action approach achieves sufficient measurement precision for mode selection without incurring excessive time loss during normal data transmission operations.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS11657859B2Memory device, controller controlling the same, memory system including the same, and operating method thereof

Publication Date: 2023.05.23 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of operating a memory device includes receiving a training request for a data channel, detecting at least one mode parameter according to the training request, transmitting the detected mode parameter to an external device, setting at least one of an NRZ mode and a PAM4 mode to a transmission signaling mode based on mode register set setting information from the external device, and performing communications with the external device according to the set transmission signaling mode.