Latch-Loop Synchronizer Circuit for Lower Metastability Latency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multi-flop synchronizers used to reduce metastability in data synchronization suffer from significant latency, high silicon area consumption, and increased power consumption due to additional flip-flop stages.
Innovation Solution
A data synchronizer circuit comprising an input stage, a driver stage, and a keeper stage with specific buffer configurations and transistor sizes to increase the gain-bandwidth product of latch loops, reducing metastability while minimizing latency and silicon area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional flip-flop stages are added to reduce metastability, then metastability failure rate is reduced, but latency increases
Solution Approach 1:
The patent changes the parameters of the latch loop by adding a driver stage with increased drive strength and reduced loading capacitance. This modifies the electrical characteristics (drive strength, capacitance) to increase the gain-bandwidth product, enabling faster metastability resolution without adding multiple sequential stages, thus reducing latency while maintaining reliability.
2Reliability
If additional flip-flop stages are added to reduce metastability, then metastability failure rate is reduced, but silicon area consumption increases
Solution Approach 1:
Instead of adding more flip-flop stages that would increase silicon area, the patent modifies the parameters of existing latch loop components. By increasing drive strength and reducing loading capacitance through the driver stage, the system achieves better metastability resolution within the same or reduced area footprint.
3Reliability
If additional flip-flop stages are added to reduce metastability, then metastability failure rate is reduced, but power consumption increases
Solution Approach 1:
The patent reduces power consumption by optimizing the electrical parameters of the latch loop. The driver stage with increased drive strength and reduced loading capacitance enables faster settling times, which reduces the time power is consumed during metastability events. Additionally, the reduced capacitance directly lowers dynamic power consumption compared to adding more flip-flop stages.
4Speed
If buffer drive strength is increased and loading capacitance is reduced, then gain-bandwidth product increases, but device complexity increases
Solution Approach 1:
The patent segments the latch circuit into distinct functional stages: an input stage, a driver stage with optimized buffers, and a keeper stage. This segmentation allows the driver stage to be specifically optimized for speed (increased drive strength, reduced capacitance) without complicating the entire device, as other stages maintain their original simplicity.
Data Source
AI summary
A data synchronizer including an input stage, a driver stage, and a keeper stage. The input stage latches input data to a data node in response to a first clock signal transition. The driver stage has an input coupled to the data node and has an output coupled to a gain node. The keeper stage latches data asserted on the gain node back to the input stage to maintain data on the data node in response to a second transition of the clock signal. The driver stage has an increased drive strength and a reduced loading capacitance to increase the gain-bandwidth product of the latch loop to reduce metastability. A flip-flop may be configured with input and output latches each including driver stages having increased drive strength and reduced loading capacitance to increase the gain-bandwidth product of each of the latch loops to reduce metastability.