Dual-Path Electrical Clamp Circuit for ESD and Overvoltage Protection

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Solution Overview

Problem

Conventional clamp circuits are inadequate in protecting electrical circuits from both electrostatic discharge (ESD) and other overvoltage (OV) conditions during normal operation, failing to react quickly or effectively to transient voltage changes caused by events like electromagnetic interference or power surges.

Innovation Solution

An electrical protection circuit with dual control paths, one digital and one gradual, to rapidly activate a discharge path for ESD events and subtly control it for OV events, using a combination of inverters and MOSFETs to manage supply voltage variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional clamp circuit is used, then protection against ESD discharge is provided, but the circuit cannot react quickly or effectively to other overvoltage conditions during normal operation

Engineering Contradiction:
Improveprotection effectivenessVSAvoidresponse to different overvoltage conditions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The control mechanism is segmented into two independent control paths: a first control path with a first trigger element for rapid digital response to ESD events, and a second control path with a second trigger element for gradual response to powered overvoltage conditions. This segmentation allows each control path to be optimized for its specific function while working together to provide comprehensive protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control gate voltage is dynamically adjusted based on the type of overvoltage event detected. The first trigger element provides rapid voltage changes for ESD events, while the second trigger element provides gradual voltage adjustments for powered overvoltage conditions. This dynamic control allows the protection device to adapt its response characteristics to different threat levels and types.

Inventive Principle:
Principle #15Dynamics

2Reliability

If a single control path is used, then device complexity is reduced, but the circuit cannot provide both rapid ESD protection and subtle control for powered overvoltage events

Engineering Contradiction:
Improveprotection coverageVSAvoidcontrol circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Two control paths with different characteristics are merged into a single unified control mechanism that drives the same protection device. The first and second trigger elements both control the same protection device through their respective control paths, allowing comprehensive protection functionality to be achieved without proportionally increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The protection device serves multiple functions through a single device structure, controlled by two different control paths. The same protection device can rapidly respond to ESD events through the first control path and provide subtle control for powered overvoltage events through the second control path, achieving multi-functionality without requiring multiple separate protection devices.

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

3Speed

If only a digital control element is used, then rapid response to ESD events is achieved, but subtle control for small voltage changes during operation is lost

Engineering Contradiction:
Improveresponse speedVSAvoidcontrol precision
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

Different control qualities are applied to different control paths: the first control path uses a digital control element optimized for rapid response to severe ESD events, while the second control path uses an analog control element optimized for precise, gradual control during powered overvoltage events. Each control path has the local quality needed for its specific function.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The first trigger element provides excessive action for ESD protection by rapidly activating the protection device, while the second trigger element provides partial action for powered overvoltage by gradually adjusting the control gate voltage. This allows appropriate levels of control action for different threat scenarios.

Inventive Principle:
Principle #16Partial or excessive action

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

Provides robust protection against ESD and OV events by rapidly clamping supply voltages to safe levels, preventing circuit damage and maintaining operational reliability.

Implementation Method 1

an RC circuit electrically coupled between the supply voltage input and the reference potential and having a first internal node for providing a control voltage

Methodology Applied
Scientific EffectRC circuit response:

Implementation Method 2

clump circuits are used, for example, to protect other circuits and devices, such as system on a chip (SoC) devices against damages caused by certain external events... electrostatic discharge (ESD) events

Methodology Applied
Scientific EffectElectrostatic discharge: Electrostatic Discharge

Data Source

PatentEP4709092A1Electrical protection circuit, integrated circuit, and mobile communication device
Publication Date: 2026.03.11 U-BLOX
  • EP4709092A1 patent drawingFigure 1~4
  • EP4709092A1 patent drawingFigure 1~2A
  • EP4709092A1 patent drawingFigure 2A~2B

AI summary

The present disclosure relates to an electrical protection, in particular an electrical clamp circuit (10, 50, 60, 80), comprising a protection device (16) electrically coupled between a supply voltage (VDD) input (12) and a reference potential (VSS) and having a control gate (22) for selectively activating a discharge path. The clamp circuit further comprises an RC circuit (26, 66) electrically coupled between the supply voltage (VDD) input (12) and the reference potential (VSS) and having a first internal node (24) for providing a control voltage, a first control path (18) electrically coupled between the first internal node (24) and the control gate (22) of the protection device (16) and having a first trigger element (32) for triggering the protection device (16), wherein the first trigger element (32) is configured to act as a digital control element, and a second control path (20) electrically coupled between the first internal node (24) and the control gate (22) of the protection device (16) and having a second trigger element (34) for triggering the protection device (16), wherein the second trigger element (34) is configured to act as a gradual control element. The disclosure further relates to an integrated circuit (46) and a communication device (40) comprising an electrical protection circuit.