Isolated Current Sensor with Reinforced Insulation Structure

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Solution Overview

Problem

Integrated current sensors require enhanced safety isolation to protect against electrical shock, particularly in user-accessible secondary circuits, where existing technologies may not provide sufficient insulation levels to meet safety standards like UL 60950-1 and IEC 60950-1.

Innovation Solution

The development of an isolated current sensor with a reinforced insulation structure featuring multiple layers of isolation material, such as Kapton® tape or polyimide tape, and a power calculation circuit that generates a power signal from both current and voltage inputs, ensuring a minimum working voltage of 500 Vrms, along with isolation resistors to prevent voltage transfer between primary and secondary circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If basic insulation is used in current sensors, then device complexity is reduced, but safety protection against electrical shock is insufficient for user-accessible circuits

Engineering Contradiction:

Improvesafety protectionVSAvoidinsulation structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The insulation structure is divided into multiple discrete layers including basic insulation layer, supplemental insulation layer, and reinforced insulation layer. Each layer serves a specific safety function and can be independently implemented, allowing the system to achieve high safety protection while maintaining manageable complexity through modular design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite insulation structures combining different material types and properties. The basic insulation layer uses standard insulating materials, while supplemental and reinforced layers use specialized materials with higher dielectric strength and breakdown voltage characteristics, creating a multi-material system that provides superior safety protection.

Inventive Principle:

Principle #40Composite materials

2Reliability

If reinforced insulation with multiple layers is implemented, then safety protection equivalent to double insulation is achieved, but device complexity and manufacturing complexity increase

Engineering Contradiction:

Improvesafety protectionVSAvoidinsulation application

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The basic insulation layer is applied first during the primary manufacturing process, establishing the foundation before secondary insulation layers are added. This preliminary action allows subsequent supplemental and reinforced insulation layers to be applied in a systematic manner, reducing manufacturing complexity despite the multi-layer structure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The insulation layers are structured in a nested configuration where supplemental and reinforced insulation layers are positioned around and in conjunction with the basic insulation layer. This nested arrangement optimizes space utilization and simplifies the assembly process by allowing layers to be integrated in a hierarchical manner.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If isolation structures with multiple insulation layers are used, then electrical shock protection is enhanced, but the device size and volume increase

Engineering Contradiction:

Improveelectrical shock protectionVSAvoidsensor volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent utilizes thin film insulation layers with high dielectric strength to provide reinforced protection without substantial volume increase. These thin film structures deliver the required electrical isolation and safety protection while maintaining a compact overall device form factor.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The multiple insulation layers are arranged in a dimensional configuration that optimizes space utilization. By stacking layers in the vertical dimension rather than expanding horizontally, the patent achieves enhanced electrical shock protection while minimizing the overall volume and footprint of the current sensor device.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 robust electrical shock protection equivalent to double insulation, ensuring user safety by maintaining a reinforced isolation rating and preventing hazardous voltage levels from reaching the secondary circuit.

Implementation Method 1

The magnetic field transducer generates a signal having a magnitude proportional to the magnetic field induced by a current that flows through the current conductor

Methodology Applied

Scientific EffectMagnetic field induction: Electromagnetic Induction

Implementation Method 2

there is a certain amount of insulation required to create a protective isolation barrier between primary and secondary circuits

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS10718794B2Current sensor with power calculation

Publication Date: 2020.07.21 ALLEGRO MICROSYSTEMS LLC

AI summary

A current sensor integrated circuit including a magnetic field sensing element, a current conductor, an insulation structure, and a power calculation circuit is configured to meet safety isolation requirements. Isolation resistors allow for voltage from a high voltage side to be sensed at a low voltage side of the circuit. The insulation structure, current sensor package, and isolation resistors can achieve at least 500 Vrms isolation.