MLSCR ESD Protection with Dynamic Voltage Control
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Solution Overview
Problem
Modified lateral silicon-controlled rectifiers (MLSCRs) in ESD protection devices often have high or low trigger and holding voltages, are prone to latch-up, and cannot be simultaneously turned on, leading to non-uniform turn-on phenomena and slow turn-on speeds, which affect their protection capability.
Innovation Solution
Incorporating a voltage control circuit that provides a current path from the control terminal of the MLSCR to either the first or second line, allowing for reduced trigger voltage and enhanced turn-on speed, while preventing latch-up by stopping the current path during normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a voltage control circuit provides a current path from the control terminal to the first line, then the turn-on speed of the MLSCR is enhanced, but the trigger voltage becomes too low causing non-uniform turn-on phenomenon
Solution Approach 1:
The patent applies dynamics by making the trigger voltage dynamically adjustable through the voltage control circuit. The circuit switches between two trigger voltage levels (first trigger voltage when current path is provided, second trigger voltage when not provided) based on operational conditions, allowing the MLSCR to achieve both fast turn-on speed and uniform turn-on behavior by adapting the trigger voltage to the specific operational context.
2Speed
If the trigger voltage of the MLSCR is decreased to enhance turn-on speed, then the turn-on speed is improved, but the latch-up effect occurs
Solution Approach 1:
The patent uses dynamics by implementing a controllable current path that adjusts the trigger voltage based on operational mode. During ESD protection events, the current path is activated to provide a low trigger voltage for fast turn-on. During normal operation, the current path is deactivated to maintain a higher trigger voltage that prevents latch-up, thus dynamically resolving the contradiction between fast turn-on and latch-up prevention.
3Adaptability or versatility
If multiple MLSCRs are controlled simultaneously, then the protection coverage is improved, but the non-uniform turn-on phenomenon occurs
Solution Approach 1:
The patent applies local quality by providing individual voltage control circuits for each MLSCR device. Each control circuit can independently adjust the trigger voltage of its associated MLSCR based on local conditions, ensuring that all MLSCRs turn on uniformly across different locations in the circuit, thus resolving the non-uniform turn-on phenomenon while maintaining comprehensive protection coverage.
Data Source
AI summary
An electrostatic discharge (ESD) protection device including a modified lateral silicon-controlled rectifier (MLSCR) and a voltage control circuit is provided. The MLSCR has a first terminal, a second terminal and a control terminal connected to a first P+-type doped region, where the first terminal and the second terminal are electrically connected to a first line and a second line, respectively. The voltage control circuit is electrically connected to the first line, the second line and the control terminal. When an electrostatic pulse is appeared on the first line, the voltage control circuit provides a current path from the first line to the control terminal. When an input signal is supplied to the first line, the voltage control circuit receives a power voltage, and stops providing the current path according to the power voltage.