ESD Protection Switch Control for Low-Leakage Thin-Oxide MOS
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Solution Overview
Problem
Existing thin-oxide MOS transistors in electronic devices are vulnerable to breakdown during electrostatic discharge (ESD) events due to high voltage, and conventional clamp cells provide inadequate ESD protection with excessive current leakage, impacting device performance.
Innovation Solution
The ESD protection circuitry incorporates a protection switch and switch controller with thick oxide components, controlled by a switch controller to disconnect or connect the external pin from internal circuitry based on voltage supply status and ESD events, using an ESD clamp cell to limit voltage and prevent leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thin-oxide clamp cells are used to protect thin-oxide MOS transistors during ESD events, then ESD protection is improved, but current leakage increases significantly
Solution Approach 1:
The protection switch transitions from a static always-on design to a dynamic controlled design. The switch controller dynamically adjusts the switch state based on real-time detection of ESD events and power supply status, enabling the circuit to adapt its protection level and leakage characteristics according to operational conditions.
Solution Approach 2:
The switch controller implements feedback mechanisms by monitoring ESD event detection signals and power supply status signals, then adjusting the protection switch state accordingly. This closed-loop control enables the system to respond to changing conditions and optimize the balance between protection and leakage.
2Ease of operation
If the protection switch is always conducting to maintain circuit connectivity, then signal transmission is improved, but the thin-oxide MOS transistors become vulnerable to ESD damage
Solution Approach 1:
The protection switch transitions from a static always-on design to a dynamic controlled design. The switch controller dynamically adjusts the switch state based on real-time detection of ESD events and power supply status, enabling the circuit to adapt its protection level and leakage characteristics according to operational conditions.
Solution Approach 2:
The system detects ESD events and power supply status in advance and takes preventive action by controlling the protection switch to disconnect the external pin from internal circuitry before ESD damage can occur to the thin-oxide MOS transistors.
3Reliability
If the protection switch is always non-conducting to protect against ESD, then transistor protection is improved, but normal signal transmission is blocked
Solution Approach 1:
The protection switch transitions from a static always-on design to a dynamic controlled design. The switch controller dynamically adjusts the switch state based on real-time detection of ESD events and power supply status, enabling the circuit to adapt its protection level and leakage characteristics according to operational conditions.
Solution Approach 2:
The protection switch operates in periodic cycles of conducting and non-conducting states based on detected conditions. During normal operation, the switch conducts to allow signal transmission; upon detecting ESD events or power supply issues, it transitions to non-conducting state to provide protection.
Data Source
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AI summary
The present disclosure relates to electrostatic discharge (ESD) protection circuitry of an electronic device, which is capable of protecting thin-oxide metal-oxide-semiconductor (MOS) transistors within the electronic device during an ESD event and/or a power-on transient stage without large current leakage. The disclosed ESD protection circuitry at least includes a protection switch and a switch controller. The protection switch is coupled between an external pin of the electronic device and internal circuitry of the electronic device, which is composed of thin-oxide MOS transistors. The switch controller is configured to control the protection switch to be conducting or non-conducting based on both a status of a first voltage supply powering the ESD protection block and a presence of an ESD event at the external pin, such that the external pin is electrically connected to or disconnected from the internal circuitry.