Floating Tap Identification for Decision Feedback Equalization
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Solution Overview
Problem
Conventional data receivers face challenges in closing the timing of direct-feedback decision feedback equalizers (DFEs) at high data rates due to smaller unit intervals, leading to increased power and area consumption, especially in memory systems with reflective channel responses, where dominant taps are often unknown and require manual configuration.
Innovation Solution
A multi-tap DFE is implemented with a method to automatically identify and use the most dominant taps as floating taps, configuring the DFE to balance performance and power/area usage, using resistor and capacitor DACs to generate offsets for coefficient determination and reconfiguration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct-feedback DFE is used at high data rates, then equalization performance is improved, but power consumption and area increase
Solution Approach 1:
The patent extracts only the most dominant taps from the full DFE structure to be implemented as floating taps. By identifying and selecting only the top K dominant taps based on channel impulse response analysis, the implementation achieves essential equalization performance while removing unnecessary taps, thereby reducing power consumption and area without significantly compromising overall equalization effectiveness.
Solution Approach 2:
The patent applies local quality by making different taps have different implementation characteristics. The dominant taps are implemented as floating taps with full precision and flexibility, while non-dominant taps are either reduced in precision or eliminated entirely. This differential treatment optimizes the balance between performance and resource consumption by allocating resources preferentially to the most impactful taps.
2Reliability
If manual configuration of dominant taps is performed, then DFE performance can be optimized, but device complexity and ease of operation are worsened
Solution Approach 1:
The patent implements self-service by enabling the DFE to automatically identify its own dominant taps through channel impulse response analysis. The system performs self-configuration by analyzing the channel characteristics, determining which taps are dominant, and setting their coefficients accordingly without requiring external manual intervention. This eliminates the need for complex manual configuration while maintaining optimized performance.
Solution Approach 2:
The patent applies preliminary action by performing channel impulse response analysis and dominant tap identification during the training phase before actual data transmission begins. By pre-determining the dominant taps and their coefficients during initialization, the system prepares the optimal configuration in advance, eliminating the need for complex real-time adjustments or manual configuration during operation.
3Measurement precision
If all taps are implemented with full precision, then equalization accuracy is improved, but area and power consumption increase
Solution Approach 1:
The patent applies partial action by implementing only the necessary subset of taps (the dominant ones) with full precision, rather than implementing all taps with full precision. By selecting only the top K dominant taps that contribute most significantly to equalization performance, the system achieves sufficient accuracy while using fewer high-precision elements, thereby reducing area and power consumption.
Data Source
AI summary
Various embodiments provide for identifying and training a floating tap for decision feedback equalization. For some embodiments, the identification and training of the floating tap described herein can be part of a circuit for receiver block of a system, such as a memory system.