Pseudo-Bidirectional ESD Circuit With Harmonic Filtering

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Solution Overview

Problem

Existing electrostatic discharge protection devices in electronic devices often cause disturbances and generate harmonics, affecting the operation of neighboring circuits or components, and their presence can hinder the reliability of these devices.

Innovation Solution

A pseudo-bidirectional electrostatic discharge protection device is introduced, featuring diodes and capacitive elements with specific capacitance values, including a third diode with higher capacitance than the first and second diodes, and additional capacitive and resistive elements to minimize harmonic production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrostatic discharge protection devices are added to protect integrated circuits, then reliability against electrostatic discharge is improved, but disturbances and harmonics are generated that affect adjacent circuits

Engineering Contradiction:

Improveprotection against electrostatic dischargeVSAvoidharmonics and disturbances

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces capacitive elements as intermediary components connected in parallel with the protection diodes. These capacitors act as mediators that filter out harmonics and disturbances generated by the electrostatic discharge protection device, allowing the protection function to remain while reducing the harmful effects on adjacent circuits.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the electrical parameters of the protection device by adding capacitive elements with specific capacitance values. This changes the frequency response and impedance characteristics of the protection circuit, enabling it to suppress harmonics while maintaining electrostatic discharge protection capability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If protection devices are integrated into the circuit, then electrostatic discharge protection is achieved, but the operation of adjacent circuits is impeded

Engineering Contradiction:

Improveelectrostatic discharge protectionVSAvoidoperation of adjacent circuits

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The capacitive elements serve as intermediary filtering components that decouple the protection device from adjacent circuits. By filtering out disturbances and harmonics, they prevent the protection device from interfering with the normal operation of neighboring circuits while maintaining the protection function.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If standard protection diodes are used, then electrostatic discharge protection is provided, but significant harmonic power is generated

Engineering Contradiction:

Improveelectrostatic discharge protectionVSAvoidharmonic power

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The capacitive elements are introduced as intermediary filtering components connected in parallel with the protection diodes. These capacitors specifically target and filter out harmonic frequencies generated during electrostatic discharge events, reducing the harmonic power while preserving the protection function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the electrical parameters of the protection circuit by adding capacitance in parallel with the diodes. This modifies the impedance characteristics and frequency response, enabling the circuit to suppress harmonic generation while maintaining effective electrostatic discharge protection.

Inventive Principle:

Principle #35Parameter changes

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 solution effectively reduces the power of harmonics and disturbances, enhancing the reliability of electronic devices by minimizing interference between terminals and improving the operational stability of integrated circuits and components.

Implementation Method 1

a third diode connecting the internal node to a third terminal for applying a reference potential, in which the third diode has a capacitance greater than that of the first and second diodes

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

the first and second capacitive elements are respectively connected in parallel with the first and second diodes

Methodology Applied

Scientific EffectHarmonic filtering: Filter (electronic)

Data Source

PatentEP4432358A1Electrostatic discharge protection device

Publication Date: 2024.09.18 STMICROELECTRONICS INT NV

Figure 1~3

AI summary

The present description relates to a pseudo-bidirectional device (200) for protection against electrostatic discharge, comprising: - first and second diodes (101-1, 101-2) connecting first and second terminals (103-1, 103-2) respectively to the same internal node (105) of the device; and - a third diode (107) connecting the internal node (105) to a third terminal (109) for application of a reference potential, in which the third diode (107) has a capacitance greater than that of the first and second diodes (101-1, 101-2), the device further comprising first and second capacitive elements (201-1, 201-2) connected respectively in parallel with the first and second diodes (101-1, 101-2).