Input Transition Detector With Mirror Delay for Glitch Filtering
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Solution Overview
Problem
Conventional input transition detection circuits are prone to errors due to signal glitches, which are recognized as valid input signal transitions, leading to erroneous detection pulses and unstable system operation in electronic systems.
Innovation Solution
A glitch-free input transition detection circuit is implemented using a mirror delay circuit and an input blocking circuit to prevent signal glitches from being detected as valid transitions, ensuring stable and correct transition detection pulses by blocking invalid signal pulses and maintaining consistent pulse width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional input transition detection circuits are used, then signal transitions can be detected, but signal glitches are erroneously recognized as valid transitions causing detection errors
Solution Approach 1:
The patent applies preliminary action by introducing a delay element that delays the input signal before comparison. This delay is configured to match the minimum pulse width of valid transitions, allowing the circuit to preemptively filter out glitches that occur before the delayed signal edge arrives, thereby preventing erroneous detections before they can occur
Solution Approach 2:
The patent uses an intermediary approach by introducing a delay element as a mediator between the input signal and the transition detector. This intermediary component transforms the timing relationship of signals, creating a time window that allows valid transitions to pass through while blocking premature glitch signals from triggering false detections
2Reliability
If the input signal path is blocked to filter glitches, then detection accuracy improves, but valid signal transitions may also be blocked
Solution Approach 1:
The patent applies dynamics by making the signal path dynamically controllable through a switch element. The switch is controlled by the timing relationship between the input signal and its delayed version, automatically opening to block glitches and closing to allow valid transitions. This dynamic control enables the circuit to adapt its blocking behavior based on the actual signal characteristics in real-time
Solution Approach 2:
The circuit uses preliminary action by pre-configuring the delay element to create a time window before the actual transition detection occurs. This preliminary timing arrangement ensures that when the switch closes to allow signal passage, valid transitions are already properly timed and ready to be detected, maintaining high detection speed without sacrificing accuracy
Data Source
AI summary
A circuit for detecting a signal transition on an input signal includes a mirror delay circuit and an input blocking circuit to prevent signal glitches or undesired signal pulses from being passed to the output signal node, thereby preventing signal distortions from being detected as a valid signal transition. The input transition detection circuit generates stable and correct transition detection pulses having a consistent pulse width.