RC-Delayed Logic Buffer for ESD-Induced Signal Inversion
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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, particularly due to electrostatic discharge (ESD) events, which existing protection circuits often fail to address effectively.
Innovation Solution
A buffer circuit is designed with a delay circuit, such as an RC circuit, in series with the buffer, which increases the transition time between logical voltage levels, thereby preventing unwanted output signal transitions by ensuring the output signal maintains a constant logical voltage level during short-duration input signal logic inversions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing protection circuits are used, then ESD protection is provided, but unwanted output signal transitions are triggered by short-duration input signal logic inversions
Solution Approach 1:
A delay circuit is introduced as an intermediary component between the input signal and the buffer circuit. This delay circuit filters out short-duration logic inversions caused by ESD events while allowing legitimate signal transitions to pass through, thereby preventing unwanted output signal transitions without compromising ESD protection capability
Solution Approach 2:
The delay circuit performs preliminary filtering of the input signal before it reaches the buffer circuit. By extending the transition time of logic signals in advance, the system prevents spurious output transitions before they can occur, addressing the harmful effect at its source
2Object-generated harmful factors
If the transition time of output signal is increased using a delay circuit, then unwanted output signal transitions are prevented, but the response time of the buffer circuit increases
Solution Approach 1:
The delay circuit applies time extension only to transient logic inversions caused by ESD events, while allowing normal signal transitions to maintain their original timing characteristics. This selective filtering approach stabilizes output signals during harmful events without introducing unnecessary delays during normal operation
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 output signal transitions triggered by short-duration logic inversions, ensuring a constant logical voltage level and preventing unwanted power-on sequences in response to ESD events, thus enhancing the protection of ICs.
Implementation Method 1
A buffer circuit is designed with a delay circuit, such as an RC circuit, in series with the buffer, which increases the transition time between logical voltage levels
Data Source
AI summary
A buffer circuit includes an input terminal, 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 is configured to increase a transition time between logical voltage levels of an output signal generated at the output terminal relative to a transition time between logical voltage levels of an input signal received at the input terminal, and the transition time of the output signal is based on a duration of a logic inversion of the input signal.