Analog Rotational Sensor Signal Processing

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Solution Overview

Problem

Existing rotational sensors face limitations in speed and accuracy due to digital processing of analog signals from Hall effect modules, which affects the determination of angular position.

Innovation Solution

A rotational sensor that employs analog signal processing on a single substrate to generate linear output from phase-shifted waveforms, using magnetic sensors and an analog signal processing module to invert and manipulate waveforms, thereby improving accuracy and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If digital processing is used to process sine and cosine signals from Hall cells, then the sensor can provide angular position information, but the speed and accuracy of angular position determination are limited due to analog to digital signal conversion

Engineering Contradiction:
Improveangular position accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces digital signal processing with analog signal processing. Specifically, analog circuits perform the calculation of angular position directly from sine and cosine signals without requiring analog-to-digital conversion. This substitution of digital electronics with analog circuitry eliminates the limitations imposed by ADC resolution and processing speed, thereby improving both accuracy and speed while reducing system complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Speed

If analog to digital signal conversion is performed, then digital processing can be implemented, but this imposes limitations on the speed of angular position determination

Engineering Contradiction:
Improveangular position determination speedVSAvoidangular position accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent eliminates analog-to-digital conversion by implementing the entire signal processing chain in analog domain. Analog circuits compute the angular position θ from sine and cosine signals using analog mathematical operations (such as arctangent calculation through analog computing elements). This removal of the ADC stage directly improves speed since there is no conversion bottleneck, while maintaining or improving accuracy through continuous analog computation rather than discrete digital approximation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If digital processing algorithms are used to compute position information, then various processing algorithms can be implemented, but this increases device complexity and reduces efficiency

Engineering Contradiction:
Improvesignal processing efficiencyVSAvoidprocessing circuit complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces complex digital processing algorithms with analog circuit implementations. Analog computing elements perform mathematical operations (addition, multiplication, arctangent calculation) directly in the analog domain using continuous signals. This approach improves productivity because analog circuits can process signals continuously without discrete sampling and computation cycles, while reducing device complexity by eliminating digital processors, memory, and complex algorithm implementation requirements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The solution provides a cost-effective and efficient rotational sensor with enhanced accuracy and speed by directly processing analog signals, reducing maximum angular error and enabling higher output resolution.

Implementation Method 1

a magnetic sensor to provide position information for generating first and second waveforms corresponding to the position information

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Data Source

PatentEP2793000B1Methods and apparatus for an analog rotational sensor
Publication Date: 2018.03.28 ALLEGRO MICROSYSTEMS LLC
  • EP2793000B1 patent drawingFigure 1~1A
  • EP2793000B1 patent drawingFigure 2~3
  • EP2793000B1 patent drawingFigure 4

AI summary

A sensor includes a signal generation module including a magnetic sensor to provide position information for generating first and second waveforms corresponding to the position information. An analog signal processing module provides an algebraic manipulation of a subset of the first waveform, the second waveform, a first inverted waveform, and a second inverted waveform, to generate a linear output signal.