Delay Locked Loop Burst Tracking for Faster Phase Locking
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Solution Overview
Problem
Conventional Delay Locked Loops (DLLs) have a prolonged locking time and are slow in correcting phase jitter due to varying delay values by only one unit delay per cycle, which affects their performance.
Innovation Solution
A DLL configuration that includes a quantization unit to measure phase differences in units of a unit delay amount, allowing the delay unit to vary its delay value by multiple unit delay amounts based on quantization results, thereby enabling faster operation and quicker correction of phase jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the delay value is varied by one unit delay per cycle, then the DLL operates with simple control logic, but the locking time is prolonged and the operation speed is slow
Solution Approach 1:
The phase difference correction is segmented into multiple adjustable steps. Instead of adjusting by one unit delay per cycle, the quantization unit divides the phase difference into multiple unit delay steps that can be adjusted in bursts, allowing faster convergence while maintaining manageable control logic through structured segmentation of the adjustment process
Solution Approach 2:
The DLL employs periodic burst adjustments where the delay value is varied by multiple unit delay amounts in periodic bursts rather than continuous single-step adjustments. This periodic burst scheme accelerates locking speed during critical phases while allowing simpler control during stable operation, resolving the contradiction between speed and complexity
2Productivity
If the delay value is varied by one unit delay per cycle, then the control mechanism remains simple, but the phase jitter correction is slow
Solution Approach 1:
The delay adjustment mechanism transitions from static single-step adjustment to dynamic multi-step burst adjustment. The quantization unit enables the system to dynamically select appropriate adjustment step sizes based on the current phase difference magnitude, allowing rapid correction when needed while maintaining simplicity when phase alignment is achieved
Solution Approach 2:
The system changes the adjustment parameter from fixed one-unit-delay-per-cycle to variable multi-unit-delay bursts. The quantization unit modifies the delay adjustment parameter dynamically, enabling faster correction speeds when phase jitter is large while reducing to simpler operation when precision is achieved, thus improving productivity without permanently increasing complexity
Data Source
AI summary
A Delay Locked Loop (DLL) includes a replica delay unit configured to delay an output clock to generate a feedback clock; a phase detector configured to measure a phase difference between the feedback clock and an input clock; a quantization unit configured to quantize the phase difference measured by the phase detector; and a delay unit configured to delay the input clock based on a quantization result from the quantization unit to generate the output clock.