Unidirectional TVS Structure for Low Clamping Voltage

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Solution Overview

Problem

Existing transient voltage suppressor (TVS) devices are unable to provide sufficient low clamping voltage during operation, which is crucial for protecting sensitive electronics from high voltage transients such as lightning strikes and electrostatic discharge.

Innovation Solution

A unidirectional transient voltage suppressor device is designed with specific doping regions and layer configurations in a semiconductor substrate, combining a TVS device and a SIDACTor device to achieve a lower clamping voltage while maintaining high peak pulse current and reverse standoff voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing TVS device structures are used, then the device can provide basic voltage suppression functionality, but the clamping voltage remains too high to effectively protect sensitive electronics

Engineering Contradiction:
Improveprotection effectivenessVSAvoiddevice structure complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines a TVS diode and a Zener diode into a single integrated device structure. The TVS diode portion provides fast transient response while the Zener diode portion provides low clamping voltage, achieving effective protection without requiring multiple separate components. This merging resolves the contradiction by integrating multiple functions into one manufacturable device.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a composite semiconductor structure with different doped regions (n-type substrate, p-type first base layer, n-type second base layer, p-type third base layer) to create the combined TVS-Zener functionality. This composite structure enables both fast response and low clamping voltage characteristics that cannot be achieved with a single material type.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If a simpler single-diode structure is used, then the device is easier to manufacture, but it cannot achieve sufficiently low clamping voltage

Engineering Contradiction:
Improvedevice structure simplicityVSAvoidclamping voltage performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

By merging the TVS diode and Zener diode into a single integrated structure with shared electrodes and coupled diodes, the patent achieves low clamping voltage performance comparable to complex multi-component solutions while maintaining a relatively simple single-device manufacturing process.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the device structure is optimized for low clamping voltage, then protection effectiveness improves, but the device complexity increases

Engineering Contradiction:
Improveclamping voltageVSAvoidlayer configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the device into distinct functional regions: a TVS diode portion with its own anode and cathode, and a Zener diode portion with its own anode and cathode. These segmented portions are electrically coupled to achieve the combined functionality, allowing optimization of each region for its specific function while maintaining overall device manageability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multi-layer composite semiconductor structure with specifically engineered doped regions enables low clamping voltage performance. The composite nature of the structure (combining different semiconductor layers and doping profiles) achieves the desired electrical characteristics while providing a unified device architecture.

Inventive Principle:
Principle #40Composite materials

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 device achieves a substantially reduced clamping voltage, ensuring effective protection against high voltage transients with improved surge performance and efficient current handling capabilities.

Implementation Method 1

Formations of at least one of: the one or more first regions in the second voltage suppression device first base layer and the doping region, and any combination thereof may form one or more NPN configurations of the transient voltage suppression device

Methodology Applied
Scientific EffectTransistor action:

Implementation Method 2

The first voltage suppression device substrate may be coupled to the first voltage suppression device first base layer, and to the first voltage suppression device second base layer. The second voltage suppression device substrate may be coupled to the second voltage suppression device first base layer and may be coupled to the second voltage suppression device second and third base layers.

Methodology Applied
Scientific EffectP-N junction breakdown: Avalanche Breakdown

Data Source

PatentEP4629778A1Unidirectional transient voltage suppressor device with low clamping voltage
Publication Date: 2025.10.08 LITTELFUSE SEMICON WUXI
  • EP4629778A1 patent drawingFigure 1
  • EP4629778A1 patent drawingFigure 2
  • EP4629778A1 patent drawingFigure 3A~3B

AI summary

A transient voltage suppression device, apparatus, structure and associated methods thereof. The device includes a first voltage suppression device having a substrate, a first base layer, and a second base layer. The substrate is coupled to the first base layer, and to the second base layer. The device includes a second voltage suppression device having a substrate, a first base layer, a second base layer, and a third base layer. The second voltage suppression device substrate is coupled to the second voltage suppression device first, second and third base layers. The second voltage suppression device first base layer includes one or more first regions. The second voltage suppression device includes a doping region disposed across at least portions of the second voltage suppression device first base layer and the second voltage suppression device substrate. The first voltage suppression device is coupled to the second voltage suppression device.