Anti-Parallel SCR ESD Protection Between Isolated Voltage Domains
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Solution Overview
Problem
Electronic devices face challenges from electro-static discharge (ESD) events due to large voltage differences, which can cause damage through increased internal operating voltages and currents, particularly in memory devices like NAND Flash, leading to potential failures.
Innovation Solution
Incorporation of an ESD protection circuit using anti-parallel silicon-controlled rectifiers (SCRs) with trigger circuits between different voltage domains, which activate during ESD events to provide low impedance protection by connecting voltage domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage domains are isolated during normal operation, then device reliability is improved, but response time during ESD events worsens
Solution Approach 1:
The patent pre-configures protection circuits (diodes, transistors, resistors) in specific arrangements between voltage domains before ESD events occur. These circuits are designed to be inactive during normal operation but automatically activate when ESD conditions are detected, eliminating the need for sequential detection and activation steps during actual ESD events.
Solution Approach 2:
The protection mechanism allows rapid transition from isolated state to connected protective state by using pre-biased circuits that immediately conduct during ESD events. The circuits skip the normal sequential operation phases and directly engage protection pathways when voltage thresholds are exceeded, achieving ultra-fast response times.
2Reliability
If ESD protection circuits are added, then protection capability is improved, but device complexity worsens
Solution Approach 1:
The patent combines multiple protection functions into integrated circuit blocks that operate between voltage domains. The protection circuits are merged with the existing voltage domain architecture, sharing common substrates and interconnect structures, which reduces overall device complexity while maintaining comprehensive ESD protection across multiple domains.
Solution Approach 2:
The protection circuits are designed to provide universal ESD protection across multiple voltage domains simultaneously. The same circuit topology and component types are reused across different voltage domain interfaces, creating a multi-functional protection system that handles various ESD scenarios without requiring separate dedicated circuits for each domain pair.
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 ESD protection circuit effectively mitigates damage from ESD events by isolating voltage domains during normal operation and rapidly connecting them during ESD, enhancing device robustness and flexibility without sequence requirements.
Implementation Method 1
electro-static discharge (ESD) events associated with the application of electricity through an external contact, an electrical short, and/or a dielectric breakdown
Data Source
AI summary
An apparatus includes a protection circuit electrically connected to first and second voltage domains. The protection circuit includes a first silicon-controlled rectifier (SCR) and a second SCR connected in anti-parallel configuration. The first SCR is configured to connect the first voltage domain and the second voltage domain based on detection of a first triggering condition. The second SCR is configured to connect the second voltage domain and the first voltage domain based on detection of a second triggering condition. The protection circuit is configured to isolate the first and second voltage domains without the triggering conditions.