Die-to-Die Inductive Communication for Galvanic Isolation

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Solution Overview

Problem

Conventional methods for achieving galvanic isolation between circuits are often expensive, space-consuming, and inefficient, making them unsuitable for applications requiring effective electrical isolation while enabling communication between circuits with different voltage references or to prevent transient signal interference.

Innovation Solution

The use of inductive communication devices with integrated circuit dies and dielectric material to provide galvanic isolation between circuits, utilizing primary and secondary coils for bi-directional communication while maintaining electrical isolation through dielectric material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional galvanic isolation techniques (optical isolators, capacitive isolators, transformer-based isolators) are used, then electrical isolation between circuits is achieved, but device cost, space consumption, and power consumption increase significantly

Engineering Contradiction:

Improvegalvanic isolation effectivenessVSAvoidisolation device size and cost

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical/electrical isolation components (transformers, optical isolators, capacitive isolators) with an inductive coupling system implemented entirely in the semiconductor domain. The isolation function is achieved through magnetic coupling between primary and secondary coils formed on separate IC dies, eliminating the need for discrete isolation components and reducing device complexity while maintaining galvanic isolation effectiveness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent embeds the isolation function within the IC die structure itself by forming coils and coupling structures directly on the semiconductor substrates. The primary and secondary coils are nested within their respective IC dies, with the isolation function integrated into the chip architecture rather than requiring external isolation components, thereby reducing overall device size and complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If conventional galvanic isolation techniques are used, then electrical isolation is achieved, but the isolation devices consume significant power

Engineering Contradiction:

Improvegalvanic isolation effectivenessVSAvoidisolation device power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces power-hungry conventional isolation techniques with an inductive coupling mechanism that operates with lower power consumption. The magnetic coupling between coils provides galvanic isolation without requiring the active components and high power consumption associated with optical isolators or transformer-based systems, thereby reducing the power footprint while maintaining isolation effectiveness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If galvanic isolation is implemented using conventional methods, then protection from transient signals and voltage differences is achieved, but the solution becomes expensive and space-consuming

Engineering Contradiction:

Improvetransient signal interference and voltage reference differencesVSAvoidisolation device area

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent replaces bulky conventional isolation components with compact inductive coupling structures implemented on IC dies. The magnetic coupling mechanism provides effective galvanic isolation against transient signals and voltage reference differences while occupying minimal space, as the coils and coupling structures are formed within the semiconductor fabrication process rather than requiring discrete external components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution effectively provides galvanic isolation while enabling efficient communication between circuits with different voltage references, reducing the risk of signal interference and improving system reliability and safety.

Implementation Method 1

inductive communication devices with integrated circuit dies and dielectric material to provide galvanic isolation between circuits, utilizing primary and secondary coils for bi-directional communication

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9219028B1Die-to-die inductive communication devices and methods

Publication Date: 2015.12.22 NXP USA INC

AI summary

An embodiment of a packaged device includes first and second package leads, a first integrated circuit (IC) die, and a sub-assembly that includes a second IC die coupled to a substrate. The first IC die has a first coil, and the second IC die has a second coil. The first and second IC die are arranged within the device so that the first and second coils are aligned with each other across a gap between the first and second IC die, and the first and second IC die are galvanically isolated from each other. The first IC die is electrically coupled to the first package lead (e.g., with a wirebond), and a substrate bond pad is electrically coupled to the second package lead (e.g., with a wirebond). The sub-assembly also may include encapsulation at least over a wirebond that electrically couples the second IC die to the substrate.