ESD Protection Circuit with Segmented Discharge Devices
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Solution Overview
Problem
Semiconductor integrated circuits using high impedance transistor technologies are vulnerable to electrostatic discharge (ESD) and require different levels of ESD protection, leading to inefficient use of layout area due to designing a single ESD solution for the highest level of protection.
Innovation Solution
The ESD-triggered protection apparatus includes a first circuit with an ESD trigger circuit and a control circuit that generates a switching pulse to direct current from an ESD pulse to the ground rail, and a second circuit with a trigger cell buffer controlling an ESD discharge device, both utilizing metal oxide semiconductor (MOS) power transistors with varying channel widths to manage different ESD levels efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single ESD solution is designed for the highest level of protection required, then the highest level of ESD protection is achieved, but layout area efficiency deteriorates for applications with less stringent requirements
Solution Approach 1:
The ESD protection system is segmented into multiple independent discharge devices (first ESD discharge device and second ESD discharge device) with different current handling capabilities. Each device can be independently activated based on the ESD event severity, allowing the system to provide appropriate protection levels without always engaging the full protection capacity, thus optimizing layout area usage.
Solution Approach 2:
The system dynamically adjusts its protection response based on the detected ESD pulse characteristics. The control circuit activates only the necessary discharge devices based on the ESD event magnitude, transitioning from a static single-size protection approach to a dynamic multi-level response that matches actual protection needs and reduces unnecessary layout area consumption.
2Reliability
If MOSFETs are sized to handle expected ESD current, then current handling capability is improved, but layout area efficiency deteriorates when ESD current is lower
Solution Approach 1:
Different regions of the ESD protection system have different current handling characteristics. The first ESD discharge device is designed with a wide current channel for high current events, while the second ESD discharge device has a narrower channel for lower current events. This local differentiation allows each component to be optimally sized for its specific function, improving overall area efficiency.
Solution Approach 2:
The system changes the operational parameters of the discharge devices based on ESD event characteristics. By varying which devices are activated and adjusting their operational states, the system adapts its current handling capability to match the actual ESD threat level, avoiding the need to always operate at maximum capacity and reducing required layout area.
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 solution provides selective ESD protection levels, reducing layout area usage and optimizing ESD handling across various applications by strategically placing the circuits within an integrated circuit's I/O ring, ensuring efficient current transfer and energy dissipation.
Implementation Method 1
electrostatic discharge (ESD) protection
Implementation Method 2
transfer a current generated by the ESD pulse to the ground rail
Data Source
AI summary
An electrostatic discharge (ESD)-triggered protection apparatus includes a first circuit and a second circuit. The first circuit includes an ESD trigger circuit to sense an ESD pulse and to generate a switching pulse responsive to the ESD pulse; a first ESD discharge device communicatively coupled to the ESD trigger circuit and responsive to the switching pulse to transfer a current generated by the ESD pulse to the ground rail; a control circuit that generates a control signal in response to the switching pulse. The second circuit includes at least one trigger cell buffer that is configured to receive the control signal and to control a second ESD discharge device such that the current generated by the ESD pulse is transferred to the ground rail.