Dynamic Hysteresis Buffer Circuit for High-Speed Noise Immunity
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Solution Overview
Problem
Existing input/output (I/O) circuits face challenges in achieving high speed operation while maintaining high noise immunity, as traditional buffers are prone to errors due to noise in incoming signals, which can lead to erroneous transitions in output signals.
Innovation Solution
The implementation of a circuit with two buffers, one having dynamic, asymmetric hysteresis and the other with fixed, wide hysteresis, allows for high noise immunity while maintaining high speed operation by transitioning between hysteresis states based on control signals, thereby reducing noise-induced errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional buffers are used, then the circuit structure is simple, but noise immunity is poor and erroneous transitions occur
Solution Approach 1:
The buffer circuit is segmented into two separate buffers: a first buffer with narrow hysteresis for fast transitions and a second buffer with wide hysteresis for noise immunity. Each buffer performs a specialized function, and their outputs are combined through logic gates to achieve both speed and reliability without requiring a completely complex redesign of the entire buffer system.
Solution Approach 2:
The outputs of the first buffer (fast response) and second buffer (noise immune) are merged through logic gates (AND/OR gates) to produce the final output signal. This combination allows the circuit to leverage the strengths of both buffers: the fast transition capability of the first buffer and the noise immunity of the second buffer, achieving both speed and reliability simultaneously.
2Reliability
If wide hysteresis is used, then noise immunity is improved, but transition speed decreases
Solution Approach 1:
The buffering function is segmented into two specialized buffers: the first buffer uses narrow hysteresis to enable fast transitions when signal levels clearly exceed thresholds, while the second buffer uses wide hysteresis to provide noise immunity during uncertain transition regions. This segmentation allows each buffer to optimize for its specific function without compromise.
Solution Approach 2:
The circuit dynamically selects which buffer's output dominates based on signal conditions. When the input signal is far from threshold values, the first buffer's fast response dominates. When the signal approaches threshold values and noise immunity becomes critical, the second buffer's wide hysteresis takes effect, dynamically adapting the response characteristics to current operating conditions.
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
This configuration effectively provides high noise immunity while ensuring high speed operation, balancing the tradeoff between noise tolerance and speed requirements in digital electronic devices and systems.
Implementation Method 1
The first buffer exhibits a first hysteresis range while configured in a first hysteresis state and exhibits a second hysteresis range while configured in a second hysteresis state
Implementation Method 2
The second buffer exhibits a third hysteresis range with a lower threshold more negative than at least a lower threshold of the second hysteresis range, and an upper threshold more positive than at least an upper threshold of the first hysteresis range
Data Source
AI summary
This disclosure provides examples of circuits, devices, systems, and methods for providing high speed operation and a high noise margin. In one implementation, a circuit includes a first buffer configured to receive an incoming signal and a control signal and to generate an output signal based on the incoming signal. The first buffer exhibits a first hysteresis range while configured in a first hysteresis state and a second hysteresis range while configured in a second hysteresis state. The first buffer is configured to transition from the first to the second hysteresis state and vice versa in response to the control signal. The circuit includes a second buffer configured to receive the incoming signal and to generate the control signal based on the incoming signal. The second buffer exhibits a third hysteresis range with a lower threshold and an upper threshold.