Pass Gate Safety Window Control for Metastable Signal Transfer
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Solution Overview
Problem
Conventional pass gate circuits experience meta-stability issues when input and control signals simultaneously transition, leading to unstable output signals due to simultaneous transitions of input signal A and control signal B.
Innovation Solution
A pass gate circuit with a control signal generating unit that creates a safety window with a predetermined width to generate an internal control signal, which maintains the signal transfer state and prevents simultaneous transitions of the input signal and the control signal, thereby stabilizing the output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pass gate circuit is used for switching operations, then signal transfer capability is improved, but meta-stability occurs when input and control signals simultaneously transition
Solution Approach 1:
The control signal generating unit detects the transition of the input signal in advance and generates a safety window signal before the simultaneous transition occurs. This preliminary action allows the internal control signal to be adjusted proactively, preventing the meta-stability problem from occurring in the first place
Solution Approach 2:
A control signal generating unit is introduced as an intermediary component between the input signal and the pass gate circuit. This intermediary detects input signal transitions, generates safety window signals, and produces internal control signals that prevent simultaneous transitions, thereby mediating the conflict between signal transfer capability and output stability
2Speed
If input signal and control signal transition simultaneously, then switching speed is improved, but output signal amplitude decreases causing meta-stability
Solution Approach 1:
The control signal generating unit applies preliminary anti-action by detecting the input signal transition and generating a safety window signal that prevents the control signal from transitioning simultaneously with the input signal. This counter-measure eliminates the harmful simultaneous transition effect before it can occur
Solution Approach 2:
The system performs preliminary detection of input signal transitions and generates internal control signals in advance, ensuring that the control signal does not transition at the same time as the input signal, thereby preventing output signal amplitude degradation
Data Source
AI summary
Provided are a pass gate circuit and a method of controlling the same for improving meta-stability when transferring signals. The gate circuit includes a signal transfer unit transferring an input signal in response to a transfer control signal, and a control signal generating unit generating a safety window having a predetermined width in response to detection of a transition of the input signal, generating an internal control signal for maintaining the signal transfer state of the signal transfer unit, and outputting the internal control signal to the signal transfer unit as the transfer control signal.