Multiple Time Domain Synchronizer With Latency Selection
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Solution Overview
Problem
Conventional memory buffer designs face challenges in efficiently controlling the timing of data and control signals due to excessive layout area requirements and inability to support variable timing needs, particularly when slower signals respond to faster signals, and struggle to maintain low read and write latencies in DDR3-compatible memory buffers.
Innovation Solution
A multiple time domain synchronizer is implemented, utilizing serially-connected registers, latency selection circuits, and synchronization circuits with unequal timing paths to manage signals across different clock phases, allowing for independent control of signals with varying timing requirements, and includes a core clock generator and insertion delay devices to ensure proper timing alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pipelines are used to delay command and control data, then timing control capability is improved, but layout area increases excessively
Solution Approach 1:
The patent merges multiple pipeline stages into a single synchronized register that can dynamically select between different delay paths. Instead of implementing separate pipelines for each delay requirement, a unified structure is created where a single register can be configured to provide variable timing delays through multiplexed control signals, thereby reducing the total layout area while maintaining timing control flexibility.
Solution Approach 2:
The synchronizer circuit is designed to perform multiple functions: it can synchronize signals across different clock domains, provide variable timing delays, and support both command and data signal processing. This multi-functional design eliminates the need for separate dedicated pipelines for each function, reducing overall circuit area while maintaining full timing control capability.
2Adaptability or versatility
If pipelines are used for signal delay, then timing flexibility is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic timing control where register enable signals and multiplexer select signals can be adjusted in real-time based on the specific timing requirements of different commands. This dynamic configuration allows the same hardware structure to adapt to variable timing needs without requiring multiple fixed pipelines, thereby reducing device complexity while maintaining timing flexibility.
Solution Approach 2:
The synchronizer allows changing of timing parameters through control signals that adjust the enable states of different register stages and select different delay paths. By parameterizing the timing behavior through controllable signals rather than fixed hardware configurations, the system achieves timing flexibility with reduced structural complexity.
3Productivity
If faster signals are used, then productivity is improved, but timing synchronization becomes more difficult
Solution Approach 1:
The patent introduces a synchronization circuit as an intermediary between faster signals and the rest of the system. This circuit includes registers that can be selectively enabled to hold or pass signals, acting as a buffer that synchronizes high-speed signals with slower clock domains. The intermediary structure manages timing mismatches without requiring the entire system to operate at the higher speed, thus maintaining productivity while simplifying synchronization.
Data Source
AI summary
A multiple time domain synchronizer includes a data pipeline containing a plurality of serially-connected delay elements therein. A latency selection circuit is provided, which has a plurality of inputs electrically coupled to outputs of a corresponding plurality of delay elements in the data pipeline. The latency selection circuit is configured to pass a data pipeline signal from an output of a selected one of the plurality of delay elements in response to a latency control signal. A synchronization circuit is provided, which is electrically coupled to an output of the latency selection circuit. This synchronization circuit, which includes first and second unequal timing paths therein, is responsive to a clock that synchronizes capture of the data pipeline signal selected by the latency selection circuit and a destination code that selects one of the first and second unequal timing paths to be traversed by the captured data pipeline signal as active.