Logic Buffer RC Delay for ESD-Induced False Trigger Suppression
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Solution Overview
Problem
Integrated circuits (ICs) face challenges in preventing unwanted output signal transitions triggered by short-duration input signal logic inversions, such as those caused by electrostatic discharge (ESD) events, as existing protection circuits may not adequately manage transient overvoltage conditions.
Innovation Solution
A buffer circuit is designed with a delay circuit, typically an RC circuit, that increases the transition time between logical voltage levels, preventing output signal transitions by synchronizing or complementing the input signal based on a threshold voltage, thereby maintaining a constant logical voltage level during short-duration logic inversions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard buffer circuit is used without delay circuit, then the circuit response speed is fast, but the circuit cannot prevent unwanted output signal transitions triggered by short-duration input signal logic inversions
Solution Approach 1:
An RC delay circuit is introduced as an intermediary component between the input signal source and the buffer circuit. This delay circuit acts as a mediator that filters short-duration logic inversions by extending their duration beyond the buffer's response threshold, thereby preventing unwanted output transitions while allowing legitimate signals to pass through unchanged.
Solution Approach 2:
The RC delay circuit performs preliminary action by pre-processing the input signal before it reaches the buffer. It extends the duration of logic inversions in advance, so that when the signal reaches the buffer, the inversions have already been transformed into durations that the buffer can recognize and filter out, preventing false transitions.
2Reliability
If an RC delay circuit is added to extend transition time, then short-duration logic inversions are filtered, but the circuit complexity increases
Solution Approach 1:
The patent employs a simple RC delay circuit composed of basic resistive and capacitive elements that are inexpensive and commonly available. This disposable-like approach uses simple, replaceable components to achieve the delay function without requiring complex or expensive circuitry, thereby minimizing the increase in device complexity while maintaining reliability.
3Productivity
If the buffer circuit responds quickly to input signals, then signal processing efficiency is high, but false triggers during ESD events occur
Solution Approach 1:
The RC delay circuit performs preliminary anti-action by pre-extending the duration of logic inversions caused by ESD events before they reach the buffer. This pre-processing ensures that when the buffer receives the signal, the harmful ESD-induced inversions have already been transformed into durations that trigger the buffer's built-in filtering, thereby preventing false triggers while maintaining efficient processing of legitimate signals.
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 buffer circuit effectively prevents unwanted power-on sequences and maintains a stable output signal during ESD events by increasing the transition time of the output signal relative to the input signal, ensuring a constant logical voltage level and reducing the risk of false triggers.
Implementation Method 1
A buffer circuit is designed with a delay circuit, typically an RC circuit, that increases the transition time between logical voltage levels
Data Source
AI summary
A buffer circuit includes an input terminal configured to receive an input signal, an output terminal, a buffer, and an RC circuit coupled in series with the buffer between the input terminal and the output terminal. The RC circuit includes a first transistor and an RC network including a resistor and a capacitor, the first transistor is coupled in series with the resistor between a power supply node and a reference node, and the buffer and the RC circuit are configured to generate an output signal based on the input signal.