Controllable Delay Circuit for Clock Signal Phase Alignment
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Solution Overview
Problem
In high-speed transaction systems, accurately aligning clock signals with address and command signals is challenging due to differences in path lengths and delays, leading to incorrect data sampling and errors, especially in DDR systems where precise timing is critical.
Innovation Solution
The implementation of a controllable delay circuit on one of the clock paths, combined with a synchronizing circuit and phase detection circuitry, allows for in-situ alignment of clock signals without adding matching elements, ensuring accurate and flexible phase adjustment independent of process variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If clock paths are matched by inserting additional elements to ensure alignment, then signal alignment is improved, but area, power consumption and clock jitter increase
Solution Approach 1:
The patent extracts the alignment function from the clock path matching approach and implements it through a separate controllable delay circuit. Instead of inserting matching elements throughout the clock paths, the invention uses a single adjustable delay element to compensate for path differences, thereby achieving alignment without the area and complexity penalties of distributed matching elements.
Solution Approach 2:
The patent employs a controllable delay circuit that can dynamically adjust its delay parameter to compensate for variations in clock path lengths. This dynamic adjustment mechanism allows the system to adapt to different operating conditions without requiring fixed matching elements, reducing both area and power consumption while maintaining alignment precision.
2Manufacturing precision
If clock paths are matched to compensate for delays, then signal alignment is improved, but power consumption increases
Solution Approach 1:
The patent separates the alignment function from the clock distribution network by using a standalone controllable delay circuit. This extraction allows the delay adjustment to be performed with minimal power consumption compared to continuously monitoring and adjusting multiple clock paths through distributed matching elements.
Solution Approach 2:
The patent changes the delay parameter of a single controllable delay circuit to achieve alignment, rather than requiring power-intensive distributed matching. The adjustable delay element can be reconfigured based on operating conditions, providing a power-efficient solution that maintains alignment without the continuous power consumption associated with active clock path matching circuits.
3Manufacturing precision
If conventional clock path matching is used, then signal alignment is improved, but clock jitter increases
Solution Approach 1:
The patent extracts the alignment function from the clock path matching approach and implements it through a separate controllable delay circuit. This separation allows the delay adjustment to be made without introducing the jitter that would result from multiple matching elements in series, as the delay circuit can be designed with lower jitter characteristics.
Solution Approach 2:
The controllable delay circuit provides dynamic adjustment capability that can adapt to varying operating conditions without introducing fixed jitter patterns. The adjustable nature of the delay element allows the system to optimize timing without the jitter penalties associated with rigid clock path matching structures.
4Manufacturing precision
If matching elements are inserted into clock paths, then signal alignment is improved, but area increases
Solution Approach 1:
The patent extracts the alignment function from distributed clock path matching and implements it through a single controllable delay circuit. This extraction concentrates the alignment functionality in one location rather than scattering matching elements throughout the clock distribution network, significantly reducing the overall area required for alignment.
Solution Approach 2:
The patent merges the delay adjustment function with the clock distribution architecture by integrating a controllable delay circuit into one of the clock paths. This consolidation approach combines multiple functions (clock distribution and alignment adjustment) into a unified structure, eliminating the need for separate matching elements and reducing total area consumption.
Data Source
AI summary
Interface circuitry transmitting transactions between an initiator and a recipient includes: a clock input receiving a clock signal; a transaction input receiving transactions; clock outputs for outputting the clock signal; transaction outputs outputting the transactions to the recipient; and synchronizing circuits clocked by the clock signal and transmitting the transactions to the transaction output in response to the clock signal. A controllable delay circuit is provided between the clock input and the synchronizing circuits. A further synchronizing circuit configured to provide a similar delay. Phase detection circuitry is arranged to detect alignment of the received clock signals. Calibration control circuitry adjusts a delay of the controllable delay circuit during calibration until the phase detection circuitry detects alignment. The calibration control circuitry controls the controllable delay circuit to generate a delay to the clock signal in dependence upon the delay that generated the alignment detected during calibration.