Darlington ESD Protection Network for High Voltage IC Latch-Up
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Solution Overview
Problem
High voltage integrated circuit (IC) devices face challenges in electrostatic discharge (ESD) protection due to latch-up issues in snapback solutions and the undesirably large size of non-snapback devices required for high voltage applications, which compromise reliability and efficiency.
Innovation Solution
An ESD protection network incorporating a common diode structure, isolation diode structures, and Darlington transistor structures is implemented within the IC device, where the Darlington transistor structures divert current to the substrate during ESD events, reducing the energy dissipation requirements of the common diode and enabling a compact high voltage solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If snapback devices are used for ESD protection, then the solution is compact, but latch-up occurs in high voltage applications making it unreliable
Solution Approach 1:
The ESD protection function is segmented into two distinct paths: a snapback device for compactness and a non-snapback device for reliability. The snapback device handles normal ESD events while the non-snapback device provides a safe discharge path for high voltage conditions, preventing latch-up by offering an alternative current path.
Solution Approach 2:
A controller circuit acts as an intermediary between the snapback and non-snapback devices. It monitors the operational state and selectively activates the appropriate discharge path, enabling the snapback device to operate reliably in high voltage applications by switching to the non-snapback path when necessary.
2Reliability
If non-snapback devices are used for high voltage ESD protection, then latch-up is avoided, but the device size becomes undesirably large
Solution Approach 1:
The ESD protection function is segmented into two distinct paths: a snapback device for compactness and a non-snapback device for reliability. The snapback device handles normal ESD events while the non-snapback device provides a safe discharge path for high voltage conditions, preventing latch-up by offering an alternative current path.
Solution Approach 2:
Instead of using a fully sized non-snapback device for all ESD events, the solution uses partial action by activating the non-snapback path only when high voltage conditions are detected. This reduces the overall device size requirement while maintaining reliability for high voltage applications.
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
This configuration enhances ESD robustness by reducing the size of the common diode and improving energy dissipation efficiency, while maintaining high voltage isolation and electromagnetic compatibility, thereby addressing the limitations of existing solutions.
Implementation Method 1
the Darlington transistor structures divert current to the substrate during ESD events
Implementation Method 2
the common diode structure is reverse biased towards the external contacts
Data Source
AI summary
An integrated circuit (IC) device including an electrostatic discharge (ESD) protection network for a high voltage application. The ESD protection network includes a common diode structure coupled between an external contact of the IC device and a substrate of the IC device, such that the common diode structure is forward biased towards the external contact, a Darlington transistor structure coupled between the external contact and the substrate of the IC device, and the Darlington transistor structure includes: an emitter node coupled to the external contact; a collector node coupled to the substrate; and a base node coupled between the emitter node of the Darlington transistor structure and the common diode structure. The at least one ESD protection network further comprises an isolation diode structure coupled between the emitter node and the base node of the Darlington transistor structure such that the isolation diode structure is forward biased towards the base node.