Integrated Hall Sensor Choke Coil for Low-Cost Current Detection

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Solution Overview

Problem

Existing current detection devices with magnetic sensors built into choke coils face challenges in assembly and manufacturing costs, and miniaturization due to complex configurations and high power attenuation from sensing resistors.

Innovation Solution

A current detection device with a choke coil composed of a pair of cores and a coreless coil, featuring a Hall IC magnetic sensor placed in a gap between the cores, using a rectangular wire and insulating resin for secure insulation and simplified assembly, and a metal case for reinforcement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a magnetic sensor is built into a choke coil for current detection, then detection accuracy is improved, but assembly complexity and manufacturing cost increase

Engineering Contradiction:

Improvecurrent detection accuracyVSAvoidassembly complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the magnetic sensor and choke coil into a single integrated component where the sensor is built directly into the coil structure. This integration reduces the number of separate parts and simplifies assembly while maintaining accurate current detection through the magnetic field generated by the coil.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The choke coil serves dual functions: as an electromagnetic component for current smoothing and as a magnetic field generator for current detection. This multi-functionality eliminates the need for separate detection components, reducing assembly complexity while preserving detection accuracy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If a magnetic sensor is built into a choke coil for current detection, then detection accuracy is improved, but manufacturing cost increases

Engineering Contradiction:

Improvecurrent detection accuracyVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

By combining the magnetic sensor and choke coil into one integrated component, the patent reduces the total number of parts that need to be manufactured and assembled. This integration simplifies the manufacturing process and reduces costs while maintaining accurate current detection capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The choke coil generates its own magnetic field for detection purposes, eliminating the need for external magnetic field generation components. This self-service approach reduces component count and manufacturing cost while preserving detection accuracy.

Inventive Principle:

Principle #25Self-service

3Reliability

If sensing resistors are used for current detection, then constant voltage and current control is achieved, but power attenuation increases due to heat generation

Engineering Contradiction:

Improvecontrol stabilityVSAvoidpower attenuation

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces the electrical sensing resistor method with a magnetic field-based detection method. Instead of measuring voltage drop across a resistor (which generates heat), the system uses the magnetic field generated by the choke coil itself to detect current, eliminating power attenuation while maintaining control stability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent converts the magnetic field, which is a byproduct of the choke coil operation, into a useful signal for current detection. This approach transforms an incidental physical phenomenon into a beneficial detection mechanism, avoiding the power loss associated with sensing resistors.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 configuration reduces assembly and manufacturing costs, miniaturizes the device, and enhances detection accuracy while withstanding vibrations, achieving reliable current detection with reduced part count and characteristic variations.

Implementation Method 1

a magnetic sensor such as a Hall element as current detection means inside the choke coil

Methodology Applied

Scientific EffectHall effect: Hall Effect

Implementation Method 2

the current detection device 1 having the magnetic sensor 1a built into the choke coil detects a magnetic flux generated by the current passing through the choke coil

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS7471178B2Current detection device

Publication Date: 2008.12.30 MURATA MFG CO LTD

AI summary

The present invention provides a low-cost current detection device having a magnetic sensor easily placed on a choke coil, wherein assembly and manufacturing costs are reduced and a product is miniaturized. A current detection device including a choke coil for smoothing an input current or an output current and a magnetic sensor 1a built into the choke coil to detect the input current or output current, wherein the choke coil is composed of: a pair of cores 5 provided with an outer magnetic leg 5a constituting a closed magnetic circuit and a center magnetic leg 5b for providing a gap; and an air core coil 6 mounted on the center magnetic leg 5b, and space 6b is provided to a part of winding of the air core coil 6 with the magnetic sensor 1a placed in the gap between the space 6b and the center magnetic leg 5b.