Single-Ended Inter-Chip Links With Constant Hamming Weight Encoding

Solution Overview

Problem

High-performance computing systems face challenges in inter-chip data transmission due to high data-dependent ground bounce and receiver reference generation issues in single-ended signaling, which increase system complexity and power consumption, and require a large number of I/O pins.

Innovation Solution

Implementing a single-ended inter-chip data transmission system using a controlled Hamming weight encoding method that adds extra data lanes to maintain a constant Hamming weight across the data bus, enabling self-referencing and reducing ground bounce, and utilizing non-return to zero (NRZ) signaling for power-efficient data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If single-ended signaling is used for data transmission, then system implementation complexity and power consumption are reduced, but data-dependent ground bounce and receiver reference generation issues increase

Engineering Contradiction:

Improvepower consumptionVSAvoidground bounce

Core Design Contradiction:

Use of energy by stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies DC balanced encoding (constant Hamming weight encoding) to change the electrical parameters of the transmitted signal. By ensuring that each encoded symbol has an equal number of logic high and logic low signals, the DC component remains constant, which eliminates data-dependent ground bounce while maintaining the simplicity of single-ended signaling architecture

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses the returned data signals themselves to generate the reference voltage at the receiver, rather than using a separate reference signal. The constant DC component of the returned signals is filtered and used as the reference, effectively copying the reference information from the data signals themselves

Inventive Principle:

Principle #26Copying

2Device complexity

If single-ended signaling is used for data transmission, then system implementation complexity is minimized, but receiver reference generation becomes problematic

Engineering Contradiction:

Improvesystem implementation complexityVSAvoidreceiver reference generation

Core Design Contradiction:

Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses the returned data signals themselves to generate the reference voltage at the receiver, rather than using a separate reference signal. The constant DC component of the returned signals is filtered and used as the reference, effectively copying the reference information from the data signals themselves

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The system generates its own reference voltage from the transmitted signals themselves. The constant DC component embedded in the returned data signals serves as the reference source, making the system self-sufficient and eliminating the need for external reference generation circuitry

Inventive Principle:

Principle #25Self-service

3Object-affected harmful factors

If extra data lanes are added for controlled Hamming weight encoding, then ground bounce is reduced, but the number of I/O pins increases

Engineering Contradiction:

Improveground bounceVSAvoidI/O pins

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent applies DC balanced encoding (constant Hamming weight encoding) to change the electrical parameters of the transmitted signal. By ensuring that each encoded symbol has an equal number of logic high and logic low signals, the DC component remains constant, which eliminates data-dependent ground bounce while maintaining the simplicity of single-ended signaling architecture

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10826536B1Inter-chip data transmission system using single-ended transceivers

Publication Date: 2020.11.03 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A single-ended inter-chip data transmission system and a single-ended inter-chip data reception system are provided for processing data. A controlled Hamming weight parallel data encoder at a transmitter device accepts N data bits with an arbitrary Hamming weight as input and generates M data bits with a controlled Hamming weight as output, wherein M is greater than N. A transmission circuit provides a time-aligned transmission of the controlled Hamming weight encoded data across a single-ended data bus.