Glitch Filter Circuit for Low-Delay Edge and Logic Stability
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Solution Overview
Problem
Existing glitch filters in electronic circuits fail to correctly filter input signals due to added delay and loopholes, which can cause signal distortion and noise, affecting circuit performance and potentially leading to operation failure.
Innovation Solution
A glitch filter comprising a high glitch filter circuit, a low glitch filter circuit, and a control circuit, with rising and falling time delay units, NAND and NOR gate circuits, and latches to generate pull-up and pull-down control signals, ensuring accurate logic level determination and reduced edge delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional high glitch filter and low glitch filter are connected in series, then high glitches and low glitches can be filtered, but the filter adds excessive delay to signal edges and creates loopholes where the output toggles to low logic level incorrectly
Solution Approach 1:
The patent applies dynamics by making the filter's response adaptive to different types of glitches. The control circuit dynamically adjusts the filtering behavior based on whether a high glitch or low glitch is detected, allowing the filter to maintain accurate glitch filtering while minimizing unnecessary delay on valid signal edges. This is achieved through the pull-up control signal and pull-down control signal that selectively activate filtering based on glitch type.
Solution Approach 2:
The patent changes the operational parameters of the filter by introducing separate delay times for high glitches (tdr) and low glitches (tdf). Instead of using a fixed delay for all filtering operations, the filter dynamically adjusts its delay parameter based on the detected glitch type, thereby optimizing the balance between filtering accuracy and signal delay. This parameter adaptation resolves the contradiction by allowing minimal delay when filtering is not needed.
2Reliability
If traditional glitch filter structure is used, then some glitches can be filtered, but loopholes occur where the output incorrectly toggles to low logic level during enabling period
Solution Approach 1:
The patent implements feedback through the control circuit that continuously monitors the input signal for glitches and generates appropriate control signals (pull-up and pull-down) to maintain correct output logic levels. When a glitch is detected, the feedback mechanism activates the appropriate control signal to prevent incorrect output toggling, thereby maintaining output stability without losing valid signal information. This feedback loop ensures that the output remains stable during the enabling period while preserving signal integrity.
3Reliability
If series connection of high glitch filter and low glitch filter is implemented, then both high and low glitches can be filtered, but the device complexity increases and performance impact occurs in propagation delay sensitive circuits
Solution Approach 1:
The patent merges the high glitch filter and low glitch filter into a single integrated filter unit with a shared control circuit. Instead of maintaining completely separate filter paths, the invention combines both filtering functions in one device that uses a unified control mechanism (the control circuit generating pull-up and pull-down signals) to handle both high and low glitches. This merging reduces device complexity while maintaining comprehensive glitch filtering capability.
Data Source
AI summary
A glitch filter is disclosed herein. The glitch filter includes a high glitch filter circuit, a low glitch filter and a control circuit. The high glitch filter circuit is configured for generating a pull-up control signal in accordance with the input signal. The low glitch filter circuit is configured for generating a pull-down control signal in accordance with the input signal. The control circuit is configured for determining the logic level of the output of the glitch filter in accordance with the pull-up control signal and the pull-down control signal. A filtering method for filtering glitches is disclosed herein as well.