PLL Tunable Oscillator Fine Control for Drift Compensation
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Solution Overview
Problem
Existing phase-locked loops (PLLs) face challenges in maintaining stable output signal frequency due to environmental changes such as temperature and supply voltage drift, which can lead to unreliable tracking of reference signals.
Innovation Solution
The implementation of a fine-tuning control code that initializes and adjusts the number of tuning-elements in a tunable oscillator, specifically through a fine bank of tuning-elements, to compensate for post-calibration drift caused by temperature and supply voltage fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of tuning-elements in a tunable oscillator is increased to compensate for temperature and supply voltage drift, then the range of drift compensation is improved, but the device complexity increases
Solution Approach 1:
The patent divides the tuning-elements into multiple banks (first bank, second bank, third bank) that can be independently controlled. This segmentation allows the system to manage complexity by organizing numerous tuning-elements into manageable groups, each contributing to the overall drift compensation range without requiring all elements to be controlled simultaneously as a single unit.
Solution Approach 2:
The patent implements dynamic control of tuning-elements based on detected drift conditions. The system selectively enables or disables specific banks of tuning-elements according to the magnitude and direction of detected temperature or supply voltage drift, allowing the complexity of the system to adapt to the actual compensation needs rather than maintaining maximum complexity at all times.
2Stability of the object's composition
If fine-tuning control is implemented to maintain stable output frequency, then the frequency stability is improved, but the control mechanism complexity increases
Solution Approach 1:
The patent employs a feedback mechanism where drift of the output signal frequency is detected, and this detection triggers selective adjustment of tuning-elements. The feedback loop monitors frequency stability and activates fine-tuning control only when drift exceeds thresholds, maintaining frequency stability while avoiding continuous complex control operations that would increase overall system complexity.
Solution Approach 2:
The patent changes the control parameter from continuous analog adjustment to discrete digital control of tuning-element banks. By controlling specific banks (first, second, third banks) in discrete steps based on detected drift conditions, the system achieves fine-tuning frequency stability through parameter changes rather than continuous complex control mechanisms.
3Reliability
If the range of drift compensation is increased to prevent lock failure and jitter, then the reliability is improved, but the number of tuning-elements required increases
Solution Approach 1:
The patent segments tuning-elements into multiple banks that can be independently activated. This segmentation allows the system to achieve extended drift compensation range by selectively combining different banks rather than requiring all tuning-elements to be continuously active, effectively increasing the compensation range while managing the quantity of simultaneously active components.
Solution Approach 2:
The patent designs the tuning-element banks to serve multiple functions: they can be individually activated for different drift conditions, combined for extended range compensation, and selectively disabled to reduce active component count. This multi-functionality allows the same physical tuning-elements to provide both fine-tuning and coarse-adjustment capabilities across different operating conditions.
Data Source
AI summary
One or more examples relate, generally to supply voltage based or temperature based fine control of a tunable oscillator of a PLL. An associated method includes: receiving one or more values indicative of temperature or supply voltage of a phase-locked loop (PLL); setting a digital fine-tuning control code to an initialization code, the initialization code at least partially based on the received one or more values indicative of temperature or supply voltage of the PLL, wherein the digital fine-tuning control code for setting a number of tuning-elements within a fine bank of a tunable oscillator; and starting, with the set digital fine-tuning control code, a process to set an initial frequency of the oscillator at or close to a target frequency. The process may be a calibration process performed before initially acquiring lock or re-acquiring lock.