Transformer-Isolated Gate Driver Signal Transmission at Lower Cost

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Solution Overview

Problem

Existing signal transmitters for insulating primary and secondary circuit systems in applications like power supplies and motor drivers face challenges in efficient signal transmission while avoiding high manufacturing costs associated with dedicated high voltage processes.

Innovation Solution

A signal transmitter design using a transformer chip with dual transformers, sealed in a single package, allows for DC insulation between a controller chip and a driver chip, enabling the use of general low-to-medium voltage processes, reducing manufacturing costs and enhancing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated high voltage processes are used to achieve DC insulation between primary and secondary circuit systems, then insulation reliability is improved, but manufacturing cost increases

Engineering Contradiction:

ImproveDC insulation reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces a transformer chip as an intermediary component between the controller chip (primary circuit) and driver chip (secondary circuit). The transformer provides galvanic isolation through magnetic coupling, achieving DC insulation without requiring expensive high voltage fabrication processes. The transformer chip acts as a mediator that transfers signals while blocking DC voltage between the two circuit systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent divides the signal transmitter into three separate chips: controller chip, transformer chip, and driver chip. This segmentation allows each component to be manufactured using appropriate processes - the controller and driver chips can use standard low-to-medium voltage processes, while the transformer chip provides the necessary isolation. This avoids the need to manufacture entire high voltage circuits using costly high voltage processes.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If general low-to-medium voltage processes are used to reduce manufacturing costs, then ease of manufacture is improved, but achieving DC insulation becomes more difficult

Engineering Contradiction:

Improvemanufacturing costVSAvoidDC insulation capability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The transformer chip serves as a mediator that enables DC insulation using standard low-to-medium voltage processes. By placing the transformer between the controller and driver chips, the system achieves galvanic isolation without requiring high voltage fabrication capabilities for the main circuit chips, thus reducing manufacturing costs while maintaining insulation reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces electrical insulation methods (which would require high voltage processes) with magnetic coupling through the transformer. This substitution allows signal transmission and DC insulation to be achieved through magnetic field coupling rather than direct electrical isolation, enabling the use of standard voltage processes for chip fabrication.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If multiple chips are used to achieve DC insulation, then insulation reliability is improved, but device complexity increases

Engineering Contradiction:

ImproveDC insulation reliabilityVSAvoidnumber of chips

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the isolation function with the signal transmission function by integrating the transformer into a multi-chip module package. While three separate chips are used (controller, transformer, driver), they are packaged together as a single integrated unit, reducing the practical complexity of system integration and connection while maintaining the insulation benefits of multiple chips.

Inventive Principle:

Principle #5Merging (Combining)

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 design achieves efficient signal transmission with DC insulation, reducing manufacturing costs and enabling applications in vehicles such as engine, electric, hybrid, and fuel cell vehicles, while maintaining reliable operation.

Implementation Method 1

a transformer that includes a primary coil to which a pulse signal is applied and a secondary coil that is electromagnetically coupled to the primary coil

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20250385679A1Signal transmitter, electronic device, vehicle, and insulated gate driver integrated circuit

Publication Date: 2025.12.18 ROHM CO LTD

AI summary

A signal transmitter includes: a transmission circuit; a reception circuit; and a plurality of insulating elements configured to transmit a plurality of signals, respectively, from the transmission circuit to the reception circuit while insulating between the transmission circuit and the reception circuit, wherein the transmission circuit includes: an oscillator circuit configured to generate a plurality of clock signals having different phases; and a plurality of driving circuits configured to drive the plurality of insulating elements in synchronization with the plurality of clock signals, respectively.