Sigma-Delta ADC Injection Branches for Multi-Quantity Sensing

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Solution Overview

Problem

Conventional sigma-delta analog-to-digital converters (ADCs) are limited to processing a single input quantity, requiring separate circuits or multiplexing for multiple inputs, which increases circuit area and power consumption.

Innovation Solution

A sigma-delta ADC with multiple injection and feedback branches capable of processing two or more different input quantities, such as voltage, capacitance, and current, using a single integrated circuit design that eliminates the need for multiplexing and reduces circuit area and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate ADCs or dedicated input circuits are used for each input quantity, then conversion accuracy for specific quantities is improved, but device area and power consumption increase

Engineering Contradiction:

Improveconversion accuracyVSAvoiddevice area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent implements a universal sigma-delta ADC that can process multiple input quantities (voltage, current, capacitance) through a single integrated circuit. The converter uses configurable injection branches that can be selectively activated based on the input type, allowing one ADC to perform the function of multiple dedicated converters, thereby reducing device area while maintaining conversion accuracy for each quantity type

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The ADC is divided into functional segments including separate injection branches for different input quantities, a shared integrator, and configurable feedback paths. Each injection branch is designed to handle specific input types (voltage, current, capacitance) while sharing common core components, enabling precise conversion for each segment without requiring fully separate circuits

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If separate ADCs or dedicated input circuits are used for each input quantity, then conversion accuracy for specific quantities is improved, but power consumption increases

Engineering Contradiction:

Improveconversion accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges multiple input processing paths into a single integrated ADC core. Different input quantities are converted to charge and injected through appropriate branches into a common integrator, combining the functionality of separate converters into one unified circuit, reducing overall power consumption while maintaining measurement precision

Inventive Principle:

Principle #5Merging (Combining)

3Area of stationary object

If multiplexing is used to share ADC resources, then device area is reduced, but conversion speed and productivity decrease

Engineering Contradiction:

Improvedevice areaVSAvoidconversion speed

Core Design Contradiction:

Area of stationary objectVSProductivity

Solution Approach 1:

The patent implements dynamic switching between different injection branches based on the input quantity type. The converter can rapidly reconfigure which branches are active without requiring time-multiplexed sharing of the ADC core, maintaining high conversion speed while sharing resources. The dynamic selection of active branches allows the system to adapt to different input types without the speed penalty of multiplexing

Inventive Principle:

Principle #15Dynamics

4Adaptability or versatility

If dedicated input circuits are used for each input quantity, then adaptability to different quantities is improved, but device complexity increases

Engineering Contradiction:

Improveadaptability to different quantitiesVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies local quality by designing specific injection branches with tailored characteristics for different input types (voltage, current, capacitance) while maintaining a uniform core ADC structure. Each branch has the specific properties needed for its input type, but all branches converge to the same integrator and quantizer, reducing overall circuit complexity compared to fully separate dedicated circuits

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP3888249B1Sigma-delta analog-to-digital converter and sensor arrangements including the same

Publication Date: 2025.10.08 SCIOSENSE BV

Figure 1
Figure 2~2A
Figure 2B

AI summary

A sigma-delta analog-to-digital converter comprises first and second injection branches (101, 102) and first and second feedback branches (121, 122) connected to an integration node (120). The first and second injection branches are configured to provide a charge injection from different input quantities selected from a differential voltage signal, a capacitance dependent signal and a current dependent signal. The first and second feedback branches are configured to provide a feedback charge injection of a fixed voltage signal or a differential voltage signal.