Switchable RC Glitch Filter for Multi-Standard Digital Signals
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Solution Overview
Problem
Existing noise suppression circuits in integrated circuits lack compatibility with different standards, as they either require glitch filtering or operate at faster speeds, necessitating a solution that can adapt to various glitch filtering requirements.
Innovation Solution
A noise suppression circuit with two data paths, one enabling glitch filtering and the other allowing faster operation without filtering, using control signals to direct input data through either path, incorporating a NOR gate, transmission gates, resistive and capacitive elements, and a Schmitt trigger inverter to selectively filter out glitches based on configurable pulse widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glitch filtering is enabled in the noise suppression circuit, then noise suppression capability is improved, but operation speed deteriorates
Solution Approach 1:
The circuit dynamically switches between two operational modes (glitch filtering enabled/disabled) based on control signals. The first data path implements glitch filtering with RC time constants, while the second data path bypasses filtering for fast operation. This dynamic reconfiguration resolves the contradiction by allowing the system to adapt its noise suppression level according to real-time requirements.
Solution Approach 2:
The noise suppression circuit is segmented into two separate data paths: a first data path with glitch filtering capability and a second data path without filtering. Each path is independently controllable, allowing the system to select the appropriate path based on whether noise suppression or speed is the priority, thereby resolving the performance contradiction.
2Reliability
If glitch filtering is enabled to filter out noises, then noise suppression is improved, but compatibility with different standards deteriorates
Solution Approach 1:
The noise suppression circuit is designed with multi-functionality to support different operational standards. By providing both a first data path with glitch filtering and a second data path without filtering, the circuit can adapt to different I/O standards (such as I2C requiring filtering and I3C requiring fast operation), making the circuit universally compatible with multiple standards.
Solution Approach 2:
The circuit dynamically adjusts its behavior based on control signals to match different standard requirements. When operating under standards requiring noise suppression, the first data path is activated. When operating under standards prioritizing speed, the second data path is activated. This dynamic adaptation enables compatibility with different standards while maintaining noise suppression capability when needed.
3Reliability
If the RC filter is continuously active to suppress glitches, then noise filtering is improved, but energy consumption increases
Solution Approach 1:
The RC filter is activated periodically or conditionally rather than continuously. Control signals enable the first data path with glitch filtering only when noise suppression is required, and disable it when fast operation is sufficient. This periodic activation reduces energy consumption while maintaining glitch filtering capability when needed.
Solution Approach 2:
The circuit dynamically switches between energy-efficient modes by activating the RC filter only when necessary. The control logic determines when to enable the first data path with filtering based on signal characteristics or system state, allowing the circuit to minimize energy consumption while maintaining reliability when glitches are present.
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
Enables compatibility with different standards like I2C and I3C by allowing selective glitch filtering, preventing initial glitches upon enabling filtering, and ensuring the noise suppression circuit operates efficiently without energy loss, thus providing filtered or unfiltered data streams based on specific requirements.
Implementation Method 1
The RC filter has a configurable pulse width that corresponds to an RC time constant of the RC filter
Implementation Method 2
a Schmitt trigger inverter
Data Source
AI summary
A noise suppression circuit includes a resistor-capacitor (RC) filter where a resistive element of the RC filter has a first terminal configured to receive an input data stream and a second terminal coupled to a circuit node Vrc and a capacitive element coupled to the circuit node, a logic gate having an input coupled to the circuit node and an output configured to provide a filtered data stream, and a switch. The switch is configured to short out the resistive element of the RC filter when the input data stream and the filtered data stream are at a same value and not short out the resistive element when the input data stream and the filtered data stream are at different values.