Source-Synchronous Clock Phase Alignment Without DLL Overhead
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Solution Overview
Problem
Source-synchronous interface standards face challenges in maintaining precise timing and signal integrity for high data rates, particularly in aligning clock and data signals without the use of costly DLL and quadrature clock generator solutions.
Innovation Solution
The implementation of clock-data phase alignment circuitry that includes clock phase adjustment circuitry, clock distribution networks, and storage circuits, utilizing adjustable delay circuits and phase detectors to achieve phase alignment between clock and data signals with reduced power and area consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DLL and quadrature clock generator solutions are used to align clock and data signals, then timing precision is improved, but power consumption and area requirements increase
Solution Approach 1:
The patent extracts only the essential phase alignment function from the complex DLL and quadrature clock generator systems. By using a simple phase detector that compares clock and data signals directly and adjusts the clock phase accordingly, the invention achieves timing precision without the excessive power consumption and area requirements of traditional solutions.
Solution Approach 2:
The invention replaces expensive, complex DLL and quadrature clock generator circuits with a simple, low-cost phase detector and clock buffer adjustment mechanism. This simplified approach achieves the necessary timing alignment function at a fraction of the power consumption and area cost of traditional methods.
2Measurement precision
If DLL and quadrature clock generator solutions are used to align clock and data signals, then timing precision is improved, but device area increases
Solution Approach 1:
The patent extracts only the essential phase alignment function from the complex DLL and quadrature clock generator systems. By using a simple phase detector that compares clock and data signals directly and adjusts the clock phase accordingly, the invention achieves timing precision without the excessive power consumption and area requirements of traditional solutions.
Solution Approach 2:
The invention replaces expensive, complex DLL and quadrature clock generator circuits with a simple, low-cost phase detector and clock buffer adjustment mechanism. This simplified approach achieves the necessary timing alignment function at a fraction of the power consumption and area cost of traditional methods.
3Reliability
If clock and data signals are transmitted separately in source-synchronous interfaces, then signal integrity is improved through common mode rejection, but phase alignment becomes more difficult to maintain
Solution Approach 1:
The patent implements a feedback mechanism where the phase detector continuously monitors the phase relationship between separately transmitted clock and data signals and adjusts the clock buffer delay accordingly. This feedback loop automatically maintains proper phase alignment despite variations in transmission conditions, solving the alignment difficulty while preserving the signal integrity benefits of separate transmission.
Solution Approach 2:
The system uses the incoming data signal itself as the reference for phase detection, eliminating the need for external alignment mechanisms. The phase detector compares the data signal phase with the clock signal and automatically adjusts the clock phase to achieve alignment, making the system self-aligning and reducing overall complexity.
Data Source
AI summary
The present embodiments relate to clock-data phase alignment circuitry in source-synchronous interface circuits. Source-synchronous interface standards require the transmission and reception of a clock signal that is transmitted separately from the data signal. On the receiver side, the clock signal must be phase shifted relative to the data signal to enable the capture of the data. Clock-data phase alignment circuitry is presented that may receive a differential clock with complementary clock signals CLK_P and CLK_N. An adjustable delay circuit and clock distribution network may delay clock signal CLK_P and provide the delayed clock signal to a storage circuit that may store the data signal. A replica clock distribution network and a replica adjustable delay circuit may form a feedback path and provide the delayed first clock signal back to clock phase adjustment circuitry which may control the adjustment of the adjustable delay circuit and the replica adjustable delay circuit.