Magnetic Field Circuit Temperature Sensing via Signal Modulation

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Solution Overview

Problem

Integrated circuits, especially analog circuits, face operational challenges due to temperature variations, requiring additional components for temperature measurement which increases cost, space, and complexity.

Innovation Solution

A method and apparatus that combine magnetic field signals with temperature signals modulated at a frequency twice that of the magnetic field signal, allowing for temperature sensing using existing PN junctions in circuits not specifically designed for temperature measurement, and processing the combined signal with an analog-to-digital converter to extract temperature data without redundant hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If dedicated temperature measurement circuitry is incorporated into the IC, then temperature sensing accuracy is improved, but device complexity and space consumption increase

Engineering Contradiction:
Improvetemperature sensing accuracyVSAvoidcircuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent reuses existing PN junctions that are already part of the magnetic field sensing circuit for dual purposes: maintaining their primary function in magnetic field detection while simultaneously utilizing them as temperature sensors. This multi-functional approach eliminates the need for dedicated temperature sensing circuitry, thereby improving temperature measurement capability without increasing device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The existing magnetic field sensing circuit components (PN junctions) serve themselves by providing temperature sensing capability as a bonus function. The circuit components that were previously only for magnetic field detection now also perform temperature measurement, making the system self-sufficient and eliminating redundant dedicated temperature sensing components

Inventive Principle:
Principle #25Self-service

2Measurement precision

If dedicated temperature measurement circuitry is incorporated into the IC, then temperature sensing capability is improved, but manufacturing cost increases

Engineering Contradiction:
Improvetemperature sensing capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

By designing the magnetic field sensing circuit with PN junctions that can serve dual purposes (magnetic field detection and temperature sensing), the patent eliminates the need for separate dedicated temperature sensing components. This reduces the total component count and simplifies the manufacturing process, thereby reducing manufacturing costs while maintaining temperature sensing capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the temperature sensing function with the existing magnetic field sensing circuit by utilizing the PN junctions already present in the circuit. This consolidation of functions into existing structures reduces the overall circuit complexity and component count, leading to lower manufacturing costs

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If dedicated temperature measurement circuitry is incorporated into the IC, then temperature sensing accuracy is improved, but space consumption on the die increases

Engineering Contradiction:
Improvetemperature sensing accuracyVSAvoiddie space
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent makes the existing PN junctions in the magnetic field sensing circuit multi-functional by utilizing them for both magnetic field detection and temperature sensing. This approach provides accurate temperature sensing without requiring additional dedicated temperature sensing components, thereby avoiding extra space consumption on the IC die

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The magnetic field sensing circuit components (PN junctions) provide temperature sensing capability as a self-service function, eliminating the need for separate dedicated temperature sensing components that would consume additional die space. The existing components serve the additional function of temperature measurement without requiring extra physical space

Inventive Principle:
Principle #25Self-service

4Measurement precision

If signal processing circuitry is added to handle temperature compensation, then temperature compensation accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature compensation accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the existing magnetic field sensing circuit components multi-functional by utilizing them for both magnetic field detection and temperature sensing. This approach provides accurate temperature measurement without requiring additional dedicated temperature sensing components, thereby avoiding extra space consumption on the IC die

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 reduces the need for dedicated temperature measurement circuitry, minimizing space and cost while maintaining accurate temperature compensation for temperature-sensitive integrated circuits.

Implementation Method 1

producing the temperature signal includes monitoring a current passing through a PN junction

Methodology Applied
Scientific EffectPN junction temperature sensing: Temperature Gradient

Implementation Method 2

modulating the temperature signal includes modulating at a frequency that is about twice a maximum frequency of the magnetic field signal

Methodology Applied
Scientific EffectFrequency modulation: Phase Modulation

Data Source

PatentEP2936180B1Systems and methods for processing temperature data or other signals
Publication Date: 2017.01.25 ALLEGRO MICROSYSTEMS LLC
  • EP2936180B1 patent drawingFigure 1
  • EP2936180B1 patent drawingFigure 2
  • EP2936180B1 patent drawingFigure 3A~3B

AI summary

In an embodiment, a circuit is configured to produce a magnetic field signal having a frequency spectrum. The circuit may also produce a temperature signal. A modulation circuit may modulate the temperature signal with a frequency outside the frequency spectrum of the magnetic field signal. The modulated signal and the magnetic field signal may be combined to produce a combined signal. A separation circuit may be configured to separate component signals from the combined signal. The separation circuit may include a first filter, which, when applied to the combined signal, produces a filtered signal; a modulation circuit configured to shift the data representing the temperature signal to a baseband frequency; and a second filter configured to separate the data representing the temperature signal from the combined signal.