RC-Triggered ESD Clamp for High-Voltage Power Rails

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Solution Overview

Problem

Current ESD protection methods for high-voltage power rails are insufficient due to latch-up issues, size restrictions, and inadequate protection capabilities, particularly for integrated circuits exposed to high voltages.

Innovation Solution

An RC-triggered clamp circuit with a resistor, capacitor, transistor, and forward-biased diodes is employed, where the RC circuit generates a triggering signal to turn on the transistor for discharging ESD, and the diodes reduce the voltage to within the clamp's operational limits, ensuring reliable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ESD protection components are added to protect ICs, then ESD protection is improved, but the device size increases

Engineering Contradiction:

ImproveESD protection capabilityVSAvoidcircuit area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The RC-triggered clamp circuit serves multiple functions: it provides ESD protection, prevents latch-up, and maintains compatibility with high-voltage operation. By combining these functions into a single circuit topology, the patent avoids the need for multiple separate protection components, thereby reducing overall circuit area while enhancing protection capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 RC-triggered clamp effectively provides ESD protection for high-voltage power rails without latch-up or size limitations, supporting voltages up to 2V and maintaining reliable operation by reducing the voltage seen by the clamp through series diodes, thus overcoming the limitations of existing solutions.

Implementation Method 1

an RC-circuit having a resistor coupled between a first node and a second node, and a capacitor coupled between the second node and a third node

Methodology Applied

Scientific EffectRC circuit time constant: Capacitance

Implementation Method 2

The RC-triggered clamp also has a transistor with a first source/drain, a gate, and a second source/drain, wherein the first source/drain is coupled to the first node, and the second source/drain is coupled to the third node

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

one or more forward-biased diodes coupled in series between a supply node and the first node

Methodology Applied

Scientific EffectDiode forward conduction: Diode

Implementation Method 4

discharging the ESD though a transistor of the RC-triggered clamp

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9548738B2High voltage RC-clamp for electrostatic discharge (ESD) protection

Publication Date: 2017.01.17 XILINX INC

AI summary

In accordance with some embodiments, an electrostatic discharge (ESD) protection circuit for high-voltage power rails includes an RC-triggered clamp having an RC-circuit having a resistor coupled between a first node and a second node, and a capacitor coupled between the second node and a third node. The RC-triggered clamp also has a transistor with a first source/drain, a gate, and a second source/drain, wherein the first source/drain is coupled to the first node, and the second source/drain is coupled to the third node. The RC-triggered clamp also has an inverter, wherein an input of the inverter is coupled to the second node, and an output of the inverter is coupled to the gate of the transistor. The ESD protection circuit also includes one or more forward-biased diodes coupled in series between a supply node and the first node.