Input Circuit Hold Logic for Ground Noise Chatter Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Parasitic characteristics of bond wires and lead pins in integrated circuits can cause glitches and chatter in signals due to noise on the ground plane, leading to misinterpretation of signals and adverse effects on circuit operation.
Innovation Solution
A circuit configuration that includes a chatter suppression circuit, which monitors changes in voltage at pads and uses a Schmitt trigger, hold low, and hold high circuits to prevent output signal changes when noise-induced changes in ground voltage are detected, thereby mitigating glitches and chatter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bond wires and lead pins are used to couple pads to external components, then electrical connection is achieved, but parasitic characteristics cause signal glitches and chatter
Solution Approach 1:
A chatter suppression circuit is introduced as an intermediary component between the noisy input signal path and the logic circuit. This circuit includes a Schmitt trigger with hysteresis that acts as a mediator to filter out noise-induced signal chatter while preserving legitimate signal transitions, thereby resolving the contradiction between maintaining electrical connection and eliminating parasitic effects.
Solution Approach 2:
The Schmitt trigger in the chatter suppression circuit employs hysteresis feedback to stabilize the output signal. The feedback mechanism creates different threshold levels for rising and falling edges, preventing multiple false transitions caused by noise and ground plane variations, thus improving signal integrity despite the presence of parasitic inductance.
2Reliability
If noise filtering is applied to suppress signal chatter, then signal integrity improves, but circuit complexity increases
Solution Approach 1:
The chatter suppression circuit serves as a dedicated intermediary module that isolates the noise-prone input path from the logic circuit. By placing this specialized filtering circuit at the input stage, noise suppression is achieved without requiring complex modifications throughout the entire circuit, thus limiting the increase in overall circuit complexity.
Solution Approach 2:
The Schmitt trigger changes the signal parameters by applying hysteresis voltage thresholds, transforming a noisy analog signal into a clean digital output. This parameter transformation approach provides effective noise filtering through a relatively simple circuit configuration, balancing signal stability improvement with acceptable circuit complexity.
Data Source
AI summary
In some examples, a circuit includes a capacitor having a first terminal and a second terminal, the first terminal coupled to a voltage supply terminal of the circuit. The circuit also includes a transistor having a transistor gate, a transistor drain, and a transistor source, the transistor source coupled to ground and the transistor drain coupled to an input terminal of the circuit. The transistor is configured to conduct responsive to a gate signal received at the transistor gate, the gate signal based on a signal provided at the second terminal of the capacitor. The circuit also includes a Schmitt trigger having a Schmitt trigger input coupled to the transistor drain.