Dynamic Source Synchronous Bus Signal Alignment
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Solution Overview
Problem
Source synchronous data bus systems face misalignment issues due to uncontrollable design margins, fabrication tolerances, and environmental factors, limiting operating frequency and requiring manual compensation techniques that are inefficient and suboptimal.
Innovation Solution
An apparatus comprising a replica distribution network, bit lag control element, and synchronous lag receiver dynamically measures and adjusts the phase alignment of data strobes and data signals, automatically compensating for misalignment caused by radial distribution and environmental variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If source synchronous protocols are used to transfer data at high bus speeds, then data transfer speed is improved, but signal misalignment occurs due to uncontrollable design margins, fabrication tolerances, and environmental factors
Solution Approach 1:
The patent implements dynamic adjustment mechanisms including delay elements and multiplexers that allow the data path timing to be adjusted in real-time based on measured skew conditions. This enables the system to adapt to changing environmental factors and maintain optimal signal alignment at high speeds
Solution Approach 2:
The patent employs feedback mechanisms where the measured skew between strobe and data signals is used to control delay elements. The system continuously monitors signal alignment and adjusts timing parameters based on this feedback, allowing automatic compensation for misalignment caused by fabrication tolerances and environmental variations
2Adaptability or versatility
If strobe distribution is added within the receiving device to reach internal synchronous receivers, then signal coverage is improved, but propagation delay increases and skews the phase of synchronous transmission
Solution Approach 1:
The patent measures and compensates for strobe distribution delay in advance before actual data transmission. By pre-characterizing the delay introduced by the radial distribution network and applying compensatory delay to the data path, the system eliminates phase skew before it affects synchronous reception
Solution Approach 2:
The patent changes the timing parameters of the data path to match the strobe distribution characteristics. By adjusting delay elements in the data path based on measured skew, the system compensates for the time loss introduced by strobe distribution and restores proper phase alignment
3Stability of the object's composition
If buffering is introduced for strobe distribution to internal receivers, then signal stability is improved, but phase skew increases and limits operating frequency
Solution Approach 1:
The patent adjusts timing parameters dynamically to compensate for buffering delays. By measuring the actual skew introduced by buffering and adjusting data path delay accordingly, the system maintains optimal setup and hold times without being limited by the fixed buffering delay
4Measurement precision
If manual compensation techniques are used for signal misalignment, then alignment accuracy can be improved, but system complexity and calibration effort increase
Solution Approach 1:
The patent implements self-calibrating mechanisms where the system automatically measures its own skew conditions and adjusts its timing parameters without external intervention. The receiving device autonomously characterizes its strobe distribution delays and applies appropriate compensation, eliminating the need for complex external calibration equipment
5Reliability
If equal propagation paths are routed for data and strobe signals, then phase alignment is improved, but design flexibility is reduced due to fabrication tolerances
Solution Approach 1:
The patent pre-characterizes the propagation path differences during manufacturing or initialization and stores these delay values for later compensation. By measuring and storing the skew parameters in advance, the system can compensate for unequal path lengths without requiring physically equal routing, providing design flexibility while maintaining alignment reliability
Data Source
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AI summary
An apparatus that compensates for misalignment on a synchronous data bus. The apparatus includes a replica distribution network, a bit lag control element, and a synchronous lag receiver. The replica distribution network receives a first signal, and generates a second signal, where the replica distribution network comprises replicated propagation characteristics of a radial distribution network for a strobe. The bit lag control element is configured to measure a propagation time beginning with assertion of the first signal and ending with assertion of the second signal, and is configured to generate a value on a lag bus that indicates the propagation time. The synchronous lag receiver is coupled to the bit lag control element, and is configured to receive a first one of a plurality of radially distributed strobes and a data bit, and is configured to delay registering of the data bit by the propagation time.