Digital Delay Lock Loop Phase Alignment at High Frequencies
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional delay lock loop (DLL) circuits in digital systems are susceptible to unwanted latencies due to characteristics of analog circuitry, particularly at higher frequencies and with smaller feature sizes, leading to errors and distortion in phase alignment between reference and output clock signals.
Innovation Solution
The implementation of digitally controlled DLL circuits that utilize a phase detector, phase accumulator, decoder, and delay element to align clock signals, combining digital and analog circuitry to mitigate latency and improve accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional analog DLL circuits are used, then the circuit structure is simple, but latency and phase alignment errors increase at high frequencies and small feature sizes
Solution Approach 1:
The patent replaces conventional analog circuitry with a digitally controlled delay element. The digital controller receives control signals and adjusts delay amounts through digital logic, eliminating the reliance on analog components that suffer from latency and phase alignment errors at high frequencies. This substitution of digital for analog mechanisms directly resolves the contradiction by maintaining simplicity while improving reliability.
Solution Approach 2:
The patent implements a delay element with multiple selectable delay amounts (first, second, third delay amounts) controlled by digital control signals. By changing the delay parameter digitally rather than through analog adjustment, the system achieves accurate phase alignment at high frequencies without the latency problems of conventional analog circuits, while maintaining a relatively simple overall structure.
2Measurement precision
If digitally controlled DLL circuits are implemented, then accuracy and reliability improve, but circuit complexity increases
Solution Approach 1:
The patent segments the delay control function into distinct digital components: a digital controller that receives control signals and a delay element with multiple selectable delay amounts. This segmentation allows precise digital control of phase alignment while keeping each component relatively simple, resolving the contradiction between precision and complexity.
Solution Approach 2:
The delay element is designed to respond to different control signals to provide multiple delay amounts, making it a multi-functional component. This universal delay element can adapt to various phase alignment requirements without requiring separate circuits for each delay setting, thereby improving precision without proportionally increasing overall circuit complexity.
3Ease of manufacture
If analog circuitry is used for delay control, then the circuit is simpler to implement, but latency errors occur particularly at higher frequencies
Solution Approach 1:
The patent substitutes digital control mechanisms for analog delay control. The digital controller and digitally controlled delay element eliminate the frequency-dependent latency errors inherent in analog circuits while maintaining ease of implementation through standard digital logic design practices. This substitution directly addresses the contradiction by improving reliability without significantly complicating manufacturing.
Data Source
AI summary
Digital delay lock circuits and methods for operating digital delay lock circuits are provided. A phase detector is configured to receive first and second clock signals and generate a digital signal indicating a relationship between a phase of the first clock signal and a phase of the second clock signal. A phase accumulator circuit is configured to receive the digital signal and generate a phase signal based on values of the digital signal over multiple clock cycles. A decoder is configured to receive the phase signal and generate a digital control word based on the phase signal. A delay element is configured to receive the digital control word. The delay element is further configured to change the relationship between the phase of the first clock signal and the phase of the second clock signal by modifying the phase of the second clock signal according to the digital control word.