D-PHY Deskew Synchronization for High-Speed Interface Skew
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Solution Overview
Problem
High-speed interface systems face challenges in compensating for phase skew between clock signals and data, which affects data interpretation in receivers, particularly in MIPI-based systems used for display devices and image sensors.
Innovation Solution
A high-speed data interface system that includes a transmission link module and a D-PHY module, utilizing deskew synchronous codes and test data to detect and correct skew between clock signals and data, with a deskew mode initiated during vertical blank periods or power-up sequences, allowing for synchronization of data with the clock signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-speed data transmission is implemented using separate clock and data channels, then transmission speed is improved, but phase skew between clock signal and data occurs
Solution Approach 1:
The patent applies preliminary action by performing deskew calibration before normal data transmission. The transmitter and receiver execute a calibration sequence where test patterns are transmitted and measured to determine optimal delay settings. This preliminary calibration establishes the correct phase relationship between clock and data channels before actual high-speed data transmission begins, preventing skew-related errors during operation.
Solution Approach 2:
The patent implements feedback through a continuous deskew calibration mechanism. The receiver measures the phase skew between received data and clock signals, generates deskew control signals based on these measurements, and feeds them back to the transmitter's delay elements. This closed-loop feedback system dynamically adjusts delay settings to maintain optimal phase alignment despite variations in temperature, voltage, or manufacturing tolerances.
2Measurement precision
If deskew calibration is performed continuously to maintain phase alignment, then data accuracy is improved, but system complexity increases
Solution Approach 1:
The patent applies periodic action by performing deskew calibration at specific intervals rather than continuously. Calibration is executed during vertical blanking periods in video transmission, during link initialization, or when skew threshold violations are detected. This periodic approach maintains data accuracy through regular calibration while avoiding the overhead of continuous calibration, thereby reducing system complexity compared to uninterrupted calibration schemes.
Solution Approach 2:
The patent implements self-service through automatic deskew calibration that requires no manual intervention. The system autonomously detects skew conditions, initiates calibration sequences, measures phase differences, and adjusts delay settings without external control. This self-calibrating capability simplifies the user interface and control logic while maintaining high data interpretation accuracy through automatic adaptation to changing conditions.
Data Source
AI summary
A high-speed interface apparatus and method of correcting skew in the apparatus are provided. A high-speed transmitter includes a transmission D-PHY module that generates and transmits a clock signal through a clock channel, generates a deskew synchronous code and test data in response to a deskew request signal, transmits the deskew synchronous code followed by the test data through a data channel, and transmits a normal synchronous code followed by normal data through the data channel in normal mode.