ADC Filter Circuit Using Signal Integration Against High-Frequency Noise

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Solution Overview

Problem

Conventional analog-to-digital converters face issues with noise and non-linearities in input signals due to parasitic coupling, leading to erroneous decisions and energy consumption in active filters, especially when generating sharp clock signal edges.

Innovation Solution

A filter circuit with multiple filter lines that convert input signals into distinguishable first-stage output signals, integrate them over a prescribed period, and generate a second-stage output signal, reducing the influence of high-frequency interferences and allowing for time-discrete output signals to be converted into a thermometer code and subsequently a binary output signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an active filter is used to filter the input signal, then filtering performance is improved, but energy consumption increases

Engineering Contradiction:

Improvefiltering performanceVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The harmful high-frequency noise components are extracted and removed from the input signal through the integration process. The integrator accumulates the input signal over a defined period, which naturally attenuates high-frequency interferences while preserving the lower frequency signal components, eliminating the need for active filtering circuits.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The filter circuit operates by integrating the input signal over a prescribed periodic time interval. This periodic integration process inherently filters out high-frequency noise that does not complete full cycles within the integration period, achieving filtering through time-domain averaging rather than frequency-domain active filtering.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If sharp edges are generated for the clock signal, then detection timing precision is improved, but interference in internal signals increases

Engineering Contradiction:

Improvedetection timing precisionVSAvoidinterference in internal signals

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The input signal is integrated over a prescribed period before the final comparison and detection stages. This preliminary integration smooths out high-frequency fluctuations and prepares a stabilized signal for subsequent processing, preventing timing jitter while avoiding the need for sharp clock edges that would cause parasitic coupling.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The integration circuit acts as a cushioning element that absorbs and dampens high-frequency noise and signal fluctuations before they reach the comparison and detection stages. This beforehand cushioning prevents interference in internal signals while maintaining detection precision.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If integration is performed over a prescribed period, then high-frequency interferences are reduced, but circuit complexity increases

Engineering Contradiction:

Improvesignal stabilityVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

An integration circuit is introduced as an intermediary stage between the input signal and the comparison/detection circuits. This intermediary integrator performs the signal smoothing function, isolating the subsequent circuitry from high-frequency interferences and simplifying the overall design by centralizing the filtering function in a single dedicated component.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach minimizes the impact of brief fluctuations and interferences on digitization by integrating signals over a period, reducing energy consumption and improving decision accuracy in analog-to-digital conversion.

Implementation Method 1

The first integration circuit is also configured to integrate the first first-stage output signals of the first input circuit over the prescribed period of time and to generate a first integration signal

Methodology Applied

Scientific EffectIntegration:

Data Source

PatentUS10284214B2Filter circuit for filtering an input signal of an analogue-to-digital converter

Publication Date: 2019.05.07 FORSCHUNGSZENTRUM JULICH GMBH

AI summary

The invention relates to a filter circuit (200) comprising at least a first filter line (210). The first filter line (210) has a first input circuit (10), a first integration circuit (20) and a first output circuit (30). The first input circuit (10) is configured in such a way that, as a function of the value of the input signal, it converts an input signal into at least two distinguishable, first first-stage output signals and relays the first-stage output signals to the first integration circuit (20, 240) during a prescribed period of time. The first integration circuit (20) is configured to integrate the first first-stage output signals of the first input circuit (10) over the prescribed period of time and to generate a first integration signal (25). The first output circuit (25) is configured to compare the first integration signal (25) to a first output reference value and to generate a first second-stage output signal (35). The invention also relates to an appertaining filtering method.