Clock Phase Alignment in Transceiver Systems
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Solution Overview
Problem
Traditional multi-gigabit transceiver designs face challenges in maintaining precise clock phase alignment across multiple outputs, especially in channel-bonded applications, due to inherent phase differences between clock domains and the use of buffers that introduce latency and uncertainty.
Innovation Solution
The implementation of a method and apparatus that uses a phase alignment device coupled with a clock generator to align clock phases between functional modules, including the injection of a static phase offset signal into a PLL's loop filter to maintain alignment of multiple outputs and control skew, allowing for sub 1 UI control at high data rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional integrated transmit and receive buffers are used to handle phase differences between clock domains, then clock phase alignment is achieved, but latency and uncertainty are introduced to both transmit and receive data paths
Solution Approach 1:
The patent extracts and eliminates the buffers from the data path by implementing a bufferless architecture. Instead of using integrated transmit and receive buffers to handle phase differences, the invention uses a common clock source distributed to both transmitter and receiver, combined with phase alignment circuits that operate without requiring buffering of the data streams themselves.
Solution Approach 2:
The patent implements a universal clock distribution system where a single common clock source serves both the transmitter and receiver functions. This common clock infrastructure provides phase alignment information to both sides simultaneously, eliminating the need for separate buffered clock domains while maintaining precise phase relationships.
2Adaptability or versatility
If buffers are used to handle phase differences, then clock domain compatibility is achieved, but uncertainty is introduced to data paths
Solution Approach 1:
The patent introduces phase alignment circuits as intermediary components that mediate between the common clock source and the transmitter/receiver data paths. These circuits provide the necessary phase adjustment and synchronization information without requiring buffers in the data paths, thereby maintaining determinism while achieving clock domain compatibility.
3Productivity
If multiple transceivers are used in channel-bonded applications, then bandwidth is increased, but skew between multiple outputs becomes difficult to control
Solution Approach 1:
The patent extends the universal common clock distribution system to serve multiple transceivers in channel-bonded configurations. Each transceiver receives phase-aligned clock signals from the common source, ensuring that all outputs remain synchronized. This approach maintains deterministic timing relationships across multiple transceivers while enabling aggregated bandwidth increases.
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 approach minimizes latency and uncertainty in clock distribution, enabling synchronous operation and maintaining alignment across multiple transceivers, thereby improving system performance and reducing the need for buffers in transceiver systems.
Implementation Method 1
a phase alignment device, coupled to the first functional module clock generator, for receiving a second functional module parallel clock and phase aligning the first functional module parallel clock to the second functional module parallel clock
Implementation Method 2
an adjustable skew amount is programmed into a phase alignment device, such as by adjusting an output phase of a charge pump output
Implementation Method 3
adjusting an output phase of a local oscillator of a phase locked loop
Data Source
AI summary
A method and apparatus for providing clock phase alignment in a transceiver system are disclosed. Circuits are provided for providing clock phase alignment to adjust and align the phase between clock domain boundaries and for maintaining alignment of multiple outputs signals.