Phase Interpolator Circuit for Real-Time Clock Skew Removal

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Solution Overview

Problem

Existing phase interpolators suffer from nonlinearity and increased jitter due to clock skew, with controllable delay cell-based interpolators lacking real-time accuracy and multi-stage interpolators consuming excessive power and area.

Innovation Solution

A phase interpolator design incorporating a decoder, digital-to-analog converter, and phase mixers to adjust weight signals and generate output clock signals, effectively removing clock skew in real-time without increasing area or power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If controllable delay cell-based phase interpolators are used to remove clock skew, then clock skew removal capability is improved, but real-time detection accuracy deteriorates because they cannot detect skew in real time

Engineering Contradiction:
Improveclock skew removal capabilityVSAvoidskew detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the phase interpolator continuously monitors clock skew in real-time and dynamically adjusts its operation based on the detected skew conditions. This closed-loop feedback system enables both skew removal and real-time detection, resolving the contradiction between skew removal capability and detection accuracy.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The phase interpolator is designed to self-detect and self-correct clock skew without requiring external intervention or additional complex detection circuits. The system uses its own output signals to monitor input skew conditions, enabling real-time detection while maintaining skew removal functionality.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If multi-stage phase interpolators are used to improve phase interpolation accuracy, then interpolation accuracy is improved, but area consumption and power consumption increase significantly

Engineering Contradiction:
Improvephase interpolation accuracyVSAvoidcircuit area
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent divides the phase interpolation function into multiple independently controllable stages, where each stage handles a specific portion of the interpolation task. This segmentation allows the system to achieve high accuracy through selective activation of stages rather than continuously operating all stages, thereby reducing area and power consumption while maintaining interpolation precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The phase interpolator employs dynamic stage activation where not all interpolation stages are activated simultaneously. Instead, the system dynamically enables only the necessary stages based on the required interpolation precision and operating conditions, optimizing the trade-off between accuracy and resource consumption.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If multi-stage phase interpolators are used to improve phase interpolation accuracy, then interpolation accuracy is improved, but power consumption increases

Engineering Contradiction:
Improvephase interpolation accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by activating only the necessary number of interpolation stages required to achieve the desired accuracy level. Rather than always operating all stages at full capacity, the system selectively engages stages based on actual needs, reducing power consumption while maintaining sufficient interpolation accuracy.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system dynamically adjusts the operation of interpolation stages based on real-time requirements, enabling or disabling stages as needed. This dynamic control optimizes power consumption by ensuring that high-precision stages are only activated when actually required, rather than operating continuously at maximum precision.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4597840A1Phase interpolator, clock data recoverer, communication device, and operating method of phase interpolator
Publication Date: 2025.08.06 SAMSUNG ELECTRONICS CO LTD
  • EP4597840A1 patent drawingFigure 1
  • EP4597840A1 patent drawingFigure 2
  • EP4597840A1 patent drawingFigure 3

AI summary

A phase interpolator includes a decoder, a digital-to-analog converter, and a first phase mixer. The decoder is configured to output a digital signal based on a control signal. The digital-to-analog converter is configured to, based on a first current, a second current, and the digital signal, adjust first to third weight signals among a plurality of target weight signals and to output the first to third weight signals. The first phase mixer is configured to determine first and second target clock signals among a plurality of input clock signals, and based on the first to third weight signals, generate a first output clock signal having a phase between the first and second target clock signals as a phase interpolation clock signal.