Sigma-Delta ADC Architecture for Multi-Input Sensor Conversion

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Solution Overview

Problem

Conventional sigma-delta analog-to-digital converters (ADCs) are limited in their ability to process multiple different input quantities, requiring separate circuits or significant resources in terms of integrated circuit area and power consumption.

Innovation Solution

A sigma-delta ADC design that incorporates multiple injection and feedback branches, allowing it to process various input quantities such as voltage, capacitance-dependent, and current-dependent signals using a single conversion core, with configurations like capacitance-dependent and differential voltage inputs, and feedback mechanisms that reduce resource requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate ADCs or dedicated input circuits are used for each input quantity, then the converter can accurately process different input quantities, but the integrated circuit area and power consumption increase significantly

Engineering Contradiction:

Improveability to process different input quantitiesVSAvoidintegrated circuit area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent implements a universal sigma-delta ADC that can process multiple input quantities (voltage, capacitance, current) through a single conversion core. Different input circuits are designed to interface with the same integration node, allowing the converter to handle various sensor types without requiring separate ADC instances, thereby reducing integrated circuit area while maintaining versatility

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges multiple input processing paths into a single conversion core. By combining voltage, capacitance, and current input circuits to share common resources (integration node, feedback mechanism, digital output), the design achieves multi-functionality without proportionally increasing circuit area, resolving the contradiction between versatility and area efficiency

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If separate ADCs or dedicated input circuits are used for each input quantity, then the converter can accurately process different input quantities, but the power consumption increases significantly

Engineering Contradiction:

Improveability to process different input quantitiesVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The universal ADC design allows a single conversion core to serve multiple input types, eliminating the need for multiple independent ADC circuits. This shared architecture reduces overall power consumption while maintaining the ability to process voltage, capacitance, and current inputs, resolving the contradiction between versatility and energy efficiency

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple injection and feedback branches are added to process different input quantities, then the converter becomes more versatile, but the device complexity increases

Engineering Contradiction:

Improveability to process different input quantitiesVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the ADC into modular components: multiple input circuits (voltage, capacitance, current) that can be selectively activated, a shared conversion core, and common feedback mechanisms. This segmentation allows the system to achieve versatility through selective activation of input paths rather than permanently complex circuitry, reducing effective complexity while maintaining adaptability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic switching between different input circuits based on the required input quantity. Through controlled activation of specific injection branches and feedback paths, the converter adapts its complexity dynamically, engaging only the necessary processing paths for the current input type, thereby achieving versatility without permanent increase in device complexity

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11855660B2Sigma-delta analog-to-digital converter and sensor arrangements including the same

Publication Date: 2023.12.26 SCIOSENSE BV

AI summary

In an embodiment, an ADC converter includes a first injection branch and a second injection branch, a first feedback branch and a second feedback branch, an integration node connected to the first and second injection branches and the first and second feedback branches, an integrator connected to the integration node and a comparator connected downstream of the integrator and configured to generate a comparator output signal to control the first and second feedback branches, wherein the first and second injection branches are configured to provide a charge injection dependent on a respective input quantity to the integration node, wherein the input quantity of the first injection branch is selected from a differential voltage signal, a capacitance dependent signal and a current dependent signal, wherein the input quantity of the second injection branch is selected from another one of the differential voltage signal, the capacitance dependent signal and the current dependent signal, and wherein the first and second feedback branches are configured to provide a feedback charge injection dependent on the comparator output signal to the integration node, the first and second feedback branches configured to receive one of a fixed voltage signal or a differential voltage signal.