Multi-Pulse Amplitude Modulation Decision Feedback Equalizer Power Modes

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Solution Overview

Problem

Conventional decision feedback equalizers (DFEs) consume equal power for both pulse-amplitude modulation (PAM4) and non-return-to-zero (NRZ) signaling protocols, leading to inefficiencies in applications like Peripheral Component Interconnect Express (PCIe), where different signaling methods are used, resulting in increased power consumption.

Innovation Solution

A DFE architecture that can be configured to operate in both PAM4 and NRZ modes, with specific components deactivated in NRZ mode to reduce power consumption, using reconfigurable tap weights to maintain proper operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional PAM4 DFE architecture is used for NRZ signaling, then the DFE can process both PAM4 and NRZ signals, but power consumption increases significantly

Engineering Contradiction:

ImproveDFE compatibility with multiple signaling protocolsVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The DFE architecture is segmented into multiple operational modes with distinct tap weight configurations. The system divides the equalization function into PAM4-specific and NRZ-specific processing paths, allowing selective activation based on the signaling protocol being used, thereby reducing power consumption in NRZ mode.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The DFE implements dynamic reconfiguration of tap weights based on the detected signaling protocol. The system can switch between PAM4 and NRZ operating modes, adjusting the equalizer coefficients dynamically to match the current protocol requirements, optimizing power efficiency for each mode.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If the same DFE architecture is used for both PAM4 and NRZ functions, then device complexity is reduced, but power consumption becomes inefficient for NRZ applications

Engineering Contradiction:

ImproveDFE architectural uniformityVSAvoidexcessive power consumption in NRZ mode

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

A single DFE architecture is designed to perform multiple functions by supporting both PAM4 and NRZ signaling protocols. The unified structure uses protocol detection and adaptive tap weight adjustment to achieve multi-functionality without requiring separate dedicated equalizers for each protocol.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system changes operational parameters (tap weights, gain factors, and processing thresholds) based on the detected signaling protocol. By adjusting these parameters dynamically, the same hardware architecture efficiently adapts to different protocols while minimizing power consumption in each operating mode.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12028191B2Multi pulse amplitude modulation signaling decision feedback equalizer having power differentiating modes and tap-weight re-configuration

Publication Date: 2024.07.02 INTEL CORP

AI summary

Some embodiments include apparatus having multiple samplers in a decision feedback equalizer (DFE). The multiple samplers include at least two samplers and are configured to be activated in a first mode of the DFE to receive first input information from a summing circuit. At least one of the samplers is configured to be deactivated in a second mode of the DFE. At least one of the samplers is configured to be activated in the second mode of the DFE to receive second input information from the summing circuit.