Isolation Chip Recess Structure for High-Voltage Signal Isolation

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Solution Overview

Problem

Existing signal transmission devices face challenges in efficiently isolating low-voltage and high-voltage circuits while allowing signal transmission between them, particularly in high-voltage applications where dielectric breakdown is a concern.

Innovation Solution

The use of transformers with magnetically coupled first and second coils, integrated with low-voltage and high-voltage circuits, to isolate and transmit signals while maintaining a high dielectric breakdown voltage, utilizing a semiconductor chip configuration with separate lead frames and mold resin encapsulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transformers with magnetically coupled coils are used to isolate low-voltage and high-voltage circuits, then dielectric breakdown voltage is improved (2500-7500 Vrms), but device complexity increases due to separate lead frames and mold resin encapsulation

Engineering Contradiction:

Improvedielectric breakdown voltageVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The device is segmented into distinct low-voltage and high-voltage circuits separated by isolated lead frames, with each circuit operating independently on its own potential reference. This segmentation enables high dielectric breakdown voltage while maintaining manageable complexity through modular isolation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Magnetically coupled transformer coils serve as an intermediary between low-voltage and high-voltage circuits, enabling signal transmission without direct electrical connection. This intermediary approach achieves reliable isolation with 2500-7500 Vrms breakdown voltage while allowing functional integration.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If separate lead frames for low-voltage and high-voltage circuits are used, then signal transmission reliability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvesignal transmission reliabilityVSAvoidease of manufacture

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple lead frames carrying different voltage potentials are merged within a single mold resin encapsulation structure. This combining approach simplifies manufacturing by treating the entire assembly as one integrated component rather than requiring separate packaging for each voltage domain.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The mold resin encapsulation serves multiple functions simultaneously: it provides mechanical support, electrical insulation, environmental protection, and structural integration for both low-voltage and high-voltage circuits. This multi-functionality improves ease of manufacture by consolidating multiple requirements into a single manufacturing process.

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 configuration effectively isolates low-voltage and high-voltage circuits, enabling reliable signal transmission with a dielectric breakdown voltage ranging from 2500 Vrms to 7500 Vrms, suitable for high-voltage applications.

Implementation Method 1

transformers with magnetically coupled first and second coils, integrated with low-voltage and high-voltage circuits, to isolate and transmit signals

Methodology Applied

Scientific EffectMagnetic coupling: Electromagnetic Induction

Data Source

PatentUS20250357434A1Isolation chip and method for manufacturing isolation chip

Publication Date: 2025.11.20 ROHM CO LTD

AI summary

An insulation chip includes a substrate, a first insulator, a first conductor, a second insulator, and a second conductor. The first conductor is embedded in the first insulator and exposed from the first insulator. The second insulator covers the first insulator and the first conductor. The second conductor is disposed on the second insulator. The first conductor, which includes an electrode pad, and the second conductor face each other in a thickness direction perpendicular to the upper surface of the first insulator. The second insulator includes insulating layers arranged on the first insulator and an exposing recess extending through the insulating layers to expose the electrode pad. The wall of the exposing recess is stepped such that the distance to the electrode pad increases from the upper surface of the first insulator toward the upper surface of the second insulator.