Isolated ADC Digital Modulation Across an EMI-Resistant Barrier

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Solution Overview

Problem

Communicating multi-bit digital data across isolated sides of an isolated ADC circuit is challenging due to synchronization requirements, susceptibility to electromagnetic interference, and inefficiencies in power consumption, which can lead to increased complexity and latency in systems like energy measurement and fault detection.

Innovation Solution

A digital modulator on the hot side converts the multi-bit ADC output to a single-bit stream, which is transmitted across the isolator without framing or synchronization signals, and a filter on the cold side reconstructs the multi-bit signal, maintaining high resolution and resilience against interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multi-bit digital data is transmitted across isolated sides with synchronization signals and framing, then data integrity is maintained, but latency and system complexity increase

Engineering Contradiction:
Improvedata integrityVSAvoidlatency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts and removes the framing and synchronization signals from the transmission protocol. By transmitting only the essential multi-bit digital data without additional control signals, the system achieves lower latency while maintaining data integrity through the inherent properties of the isolation interface and data encoding scheme.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the transmission into fixed-width multi-bit data units that can be processed and transmitted independently. This segmentation allows each data unit to cross the isolation barrier without requiring continuous synchronization, reducing overall latency while maintaining integrity through structured data formatting.

Inventive Principle:
Principle #1Segmentation

2Reliability

If multi-bit digital data is transmitted with framing and synchronization, then data integrity is ensured, but device complexity increases

Engineering Contradiction:
Improvedata integrityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the complex framing and synchronization infrastructure from the transmission system. By eliminating these additional signal paths and processing requirements, the system achieves data integrity through simpler means, reducing device complexity while maintaining reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If traditional isolation communication methods are used, then galvanic isolation is achieved, but power consumption increases

Engineering Contradiction:
Improvegalvanic isolationVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic sampling and transmission of multi-bit data across the isolation barrier. By using periodic rather than continuous transmission, the system maintains galvanic isolation effectiveness while reducing power consumption through duty-cycled operation of the isolation interface.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3635924B1Digital modulation scheme for data transfer
Publication Date: 2025.09.03 ANALOG DEVICES INT UNLTD CO
  • EP3635924B1 patent drawingFigure 1
  • EP3635924B1 patent drawingFigure 2
  • EP3635924B1 patent drawingFigure 3

AI summary

Various examples are directed to isolated analog-to-digital converter (ADC) circuits comprising a first side that is separated from a second side by an isolator. A first ADC positioned on the first side may be configured to convert a first analog input signal to a first side multi-bit digital signal. A digital modulator on the first side may be configured to convert the first side multi-bit digital signal to a first single-bit stream. A first filter positioned on the second side may be configured to receive the first single-bit stream across the first isolator and to generate a first reconstructed multi-bit digital signal using the first single -bit stream.