Clock Skew Calibration in Semiconductor Receivers Using Track Signals
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Solution Overview
Problem
In modern semiconductor devices, clock skew caused by variations in propagation delays, capacitive and inductive effects, and temperature and process variations leads to data setup and hold violations, reduced timing margins, and synchronization failures, necessitating the adjustment of clock signals for reliable data communication.
Innovation Solution
A semiconductor package and method that utilizes a receiver and controller to generate internal clock signal pairs of different phases, sample data and track signals, detect skew status, and adjust phases based on skew status using a clock shift signal to align clock signals with data signals, incorporating a track signal with a constant pattern for recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If clock signal frequency is increased to maintain performance at higher operating speeds, then communication speed improves, but clock skew increases causing data setup and hold violations
Solution Approach 1:
The patent implements dynamic clock skew calibration by continuously monitoring data sampling accuracy and adjusting clock signal phases in real-time. The calibration circuit dynamically modifies clock signal characteristics based on detected skew conditions, enabling the system to adapt to varying operating conditions and maintain reliable synchronization at high communication speeds
Solution Approach 2:
The patent employs feedback mechanisms where the calibration circuit receives feedback about data sampling accuracy and clock skew conditions. Based on this feedback, the system automatically adjusts clock signal phases to optimize timing alignment, creating a closed-loop control system that maintains synchronization reliability while operating at high speeds
2Productivity
If clock signal frequency is increased to reduce transmission time, then productivity improves, but timing precision deteriorates due to increased skew
Solution Approach 1:
The system dynamically adjusts clock signal phases through calibration circuits that continuously optimize timing alignment. This dynamic adjustment allows the system to maintain precise timing control even at high data transmission speeds, preventing timing precision deterioration that would normally occur with increased frequency
Solution Approach 2:
The patent changes clock signal parameters (phase, timing) through calibration adjustments. By modifying these parameters dynamically based on operating conditions, the system maintains timing precision while operating at high productivity levels, effectively decoupling speed from timing accuracy degradation
3Reliability
If skew calibration mechanisms are added to adjust clock signals, then synchronization reliability improves, but device complexity increases
Solution Approach 1:
The patent introduces calibration circuits as intermediary components that mediate between the clock signal source and the data processing units. These calibration circuits selectively adjust clock signals only when skew conditions are detected, providing synchronization reliability while maintaining relatively simple integration within the semiconductor package structure
4Adaptability or versatility
If multiple calibration circuits are used to adjust different clock signals, then adaptability improves, but manufacturing complexity increases
Solution Approach 1:
The patent implements calibration circuits at specific locations where clock skew problems are most likely to occur, rather than uniformly across all clock signal paths. This localized approach provides adaptability for critical timing paths while reducing overall manufacturing complexity by calibrating only where necessary
Data Source
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AI summary
A semiconductor device includes a receiver and a controller. The receiver is configured to sample a data signal and a track signal received through data lanes in response to rising edges of first and second internal clock signal pairs. The controller is configured to detect a skew status between the track signal and the first and second internal clock signal pairs, based on the number of times a specific logic level of the track signal is sampled in synchronization with each of the first and second internal clock signal pairs, and provide the receiver with a clock shift signal for calibrating a clock skew, based on the skew status.