Stacked Redundant Safety Lock Circuits for Fault-Tolerant Switching

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Solution Overview

Problem

Existing safety switching devices with on-chip redundancy are costly, complex, and limited in application due to architectural requirements, and systems with separate components are not allowed in certain safety-critical applications.

Innovation Solution

A safety switching device is constructed using two separate semiconductor substrates stacked together, forming a single component, with each substrate containing a signal processing unit, and optionally a control and storage structure, allowing independent design and reducing complexity and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate semiconductor substrates are used for redundant signal processing channels, then fault tolerance is improved, but device complexity increases

Engineering Contradiction:
Improvefault toleranceVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the safety switching device into multiple independent semiconductor substrates, each containing a separate signal processing channel. This segmentation allows each substrate to be independently designed, manufactured, and tested, improving fault tolerance while managing complexity through modular architecture. The substrates are physically separated but functionally integrated through the stack assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from planar arrangement of signal processing channels to a three-dimensional stack configuration. Multiple semiconductor substrates are stacked vertically, utilizing the vertical dimension to house redundant channels. This dimensional change reduces the horizontal footprint while maintaining channel independence, thereby improving reliability without proportionally increasing overall device complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If on-chip redundancy is implemented, then manufacturing cost is reduced, but application versatility is limited

Engineering Contradiction:
Improvemanufacturing costVSAvoidapplication versatility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

By separating redundant signal processing channels onto different semiconductor substrates rather than integrating them on a single chip, the patent enables each substrate to be manufactured using standard processes. This segmentation allows the use of conventional manufacturing techniques while still achieving redundancy, thereby controlling costs. Additionally, the modular substrates can be selectively assembled to meet different application requirements, enhancing versatility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal platform where the same basic semiconductor substrate design can serve multiple safety-critical applications. The standardized substrates with independent signal processing channels can be configured in different stack arrangements to meet various safety integrity levels and application-specific requirements, thus achieving both cost efficiency through reusability and versatility through configurability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple separate components are used, then application flexibility is improved, but regulatory approval difficulty increases

Engineering Contradiction:
Improveapplication flexibilityVSAvoidregulatory approval difficulty
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple semiconductor substrates into a single integrated stack assembly that functions as one unified safety switching device. This merging approach maintains the flexibility of having separate, independently verifiable channels while presenting a single integrated product for regulatory approval. The stack structure ensures that all channels are permanently associated, eliminating the need for complex interconnection verification during approval processes.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4086714B1Electronic safety lock
Publication Date: 2025.12.03 PILZ GMBH & CO KG
  • EP4086714B1 patent drawingFigure 1
  • EP4086714B1 patent drawingFigure 2
  • EP4086714B1 patent drawingFigure 3

AI summary

Electronic safety switching device (10) with at least one first signal processing channel (28) and a second signal processing channel (30), to which input signals can be supplied for signal processing and which provide processed output signals, wherein the first signal processing channel (28) and the second signal processing channel (30) process the supplied input signals redundantly to each other, and wherein the first signal processing channel (28) and the second signal processing channel (30) are each constructed using integrated semiconductor structures. The first signal processing channel (28) is arranged monolithically as a first integrated circuit on a first semiconductor substrate (32), and the second signal processing channel (30) is arranged monolithically as a second integrated circuit on a second semiconductor substrate (34).The first semiconductor substrate (32) and the second semiconductor substrate (34) are stacked on top of each other to form a single, one-piece electronic component (38), wherein the first integrated circuit of the first signal processing channel (28) forms a first layer of the electronic component (38) and the second integrated circuit of the second signal processing channel (30) forms a second layer of the electronic component (38). The first and second layers are parallel to each other and offset in one direction orthogonally to each other.