Integrated Thyristor ESD Protection for Mixed-Signal High Voltage Interfaces
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Solution Overview
Problem
Conventional solutions for ESD protection in mixed-signal high voltage integrated circuits face challenges such as excessive loading, voltage terminal isolation sensitivity, and increased complexity due to the need for separate isolated devices, which can compromise the reliability of low voltage interface terminals.
Innovation Solution
A protection device is designed with a substrate of a first conductivity type, featuring a thyristor region coupled to an input/output voltage terminal and diodes configured to provide dual-tub isolation between voltage terminals, allowing for built-in discharge paths and reduced area requirements, while maintaining high voltage tolerance and isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate isolated devices are used for ESD protection, then voltage terminal isolation is improved, but device complexity and area requirements increase
Solution Approach 1:
The patent combines multiple ESD protection functions into a single integrated protection device structure. The device integrates a first protection circuit for the first voltage terminal, a second protection circuit for the second voltage terminal, and a third protection circuit for the third voltage terminal within one unified structure, eliminating the need for separate isolated devices and reducing overall device complexity while maintaining isolation effectiveness.
Solution Approach 2:
The protection device performs multiple ESD protection functions simultaneously across different voltage terminals (first, second, and third voltage terminals) with different voltage levels. The single device structure provides universal protection capability for multiple terminals that would traditionally require separate dedicated protection devices, thereby reducing integration complexity.
2Reliability
If separate isolated devices are used for ESD protection, then voltage terminal isolation is improved, but area requirements increase
Solution Approach 1:
The patent merges multiple protection functions into a single compact device structure that protects multiple voltage terminals simultaneously. By integrating the first protection circuit, second protection circuit, and third protection circuit into one unified device, the total area required is significantly reduced compared to using separate isolated devices for each terminal.
3Reliability
If protection devices are added for ESD protection, then reliability is improved, but loading on voltage terminals increases
Solution Approach 1:
The protection circuits within the device dynamically respond to voltage conditions at each terminal. The circuits remain in a high-impedance state during normal operation to minimize loading, and automatically transition to a low-impedance state when ESD events are detected, providing protection only when needed. This dynamic behavior reduces overall loading on the voltage terminals compared to continuously active protection devices.
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 provides robust ESD protection and isolation for low voltage communication interface pads, reducing the risk of damage from transient signal events and improving circuit reliability with a compact design.
Implementation Method 1
The protection devices can be incorporated on-chip or at the system-level, and can maintain the voltage level at the pads within a predefined safe range by transitioning from a high impedance/low leakage state to a low impedance/high conductivity state when the voltage of the transient signal reaches a trigger voltage.
Implementation Method 2
a first decoupling component region comprising a first decoupling component anode region at least partially abutting a first decoupling component cathode region. The first decoupling component anode region is coupled to the first voltage source terminal. The first decoupling component cathode region is coupled to the input/output voltage terminal.
Data Source
AI summary
A high voltage isolation protection device for low voltage communication interface systems in mixed-signal high voltage electronic circuit is disclosed. According to one aspect, the protection device includes a semiconductor structure configured to provide isolation between low voltage terminals and protection from transient events. The protection device includes a thyristor having an anode, a cathode, and a gate, and a thyristor cathode-gate control region that is built into the protection device. The protection device is configured to provide multiple built-in path-up to power-high terminals and path-down to power-low terminals at different voltage levels. The protection device also includes independently built-in discharge paths to the common substrate that is connected to a different power-low voltage reference. The conduction paths may be built into a single structure with dual isolation regions. As a result, the protection device enables superior robustness and compact protection solutions for smart power applications.