Coupled Ring Oscillator ADC Modes for Lower Phase Noise

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Solution Overview

Problem

Ring oscillator-based ADCs face challenges with high phase noise and power consumption that do not scale with bandwidth, leading to inefficient performance in wireless local area network (WLAN) receivers, particularly in maintaining dynamic range across varying baseband bandwidths.

Innovation Solution

The configuration of ring oscillators with multiple coupled rings to reduce phase noise and quantization noise, and the implementation of a multi-mode ADC that dynamically adjusts power consumption based on bandwidth requirements by selecting the appropriate number of coupled rings and sampling frequency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a ring oscillator-based ADC is used to achieve high-speed conversion, then conversion speed is improved, but phase noise increases significantly

Engineering Contradiction:
Improveconversion speedVSAvoidphase noise
Core Design Contradiction:
SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent divides a single ring oscillator into multiple coupled rings (first ring, second ring, etc.). Each ring operates at a lower frequency individually, which reduces phase noise. The coupled structure combines their outputs to achieve the desired effective conversion speed while maintaining lower phase noise levels compared to a single high-speed ring oscillator.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the ADC operates at high bandwidth to handle varying baseband signals, then signal processing capability is improved, but power consumption increases and does not scale down

Engineering Contradiction:
Improvebandwidth handling capabilityVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent implements a multi-mode ADC that can dynamically switch between different operating modes. The system selects the appropriate number of coupled rings and sampling frequency based on the current bandwidth requirements. This allows the ADC to adapt its power consumption to match the actual signal processing needs, rather than continuously operating at maximum bandwidth and power levels.

Inventive Principle:
Principle #15Dynamics

3Object-generated harmful factors

If multiple coupled rings are used to reduce phase noise, then phase noise is reduced by approximately 10*log10(L) dB, but device complexity increases

Engineering Contradiction:
Improvephase noiseVSAvoidring oscillator structure complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges multiple ring oscillators into a coupled ring structure where the rings share common elements and are interconnected. This merging approach allows the system to achieve phase noise reduction through the combined operation of multiple rings while avoiding the full complexity of completely independent oscillators. The coupled structure enables资源共享 (resource sharing) and coordinated operation to reduce overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4462684A1Circuit and method for operating an analog-to-digital converter in multiple modes using ring oscillators
Publication Date: 2024.11.13 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • EP4462684A1 patent drawingFigure 1
  • EP4462684A1 patent drawingFigure 2A
  • EP4462684A1 patent drawingFigure 2B

AI summary

A device may include one or more ring oscillators and circuitry. The one or more ring oscillators may include a plurality of rings. The circuitry may be configured to receive a selection of a number of coupled rings and a number of phases. The circuitry may be configured to configure the one or more ring oscillators to operate at least based on the number of coupled rings. The circuitry may be configured to cause the configured one or more ring oscillators to receive an input signal and output a plurality of signals having respective phases corresponding to the number of phases. The circuitry may be configured to convert the plurality of signals to one or more digital signals.