PLL Tunable Oscillator Fine Control for Voltage and Temperature Drift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Phase-locked loops (PLLs) face challenges in maintaining the predetermined relationship between the phase or frequency of the output signal and the reference signal due to environmental changes such as temperature and supply voltage drift, which can lead to post-calibration drift and instability in the output frequency.
Innovation Solution
The proposed solution involves initializing a fine-tuning control code for a tunable oscillator in a PLL, which sets the number of tuning-elements in the fine bank of the oscillator. This initialization is based on temperature and supply voltage values, allowing for compensation of post-calibration drift by adjusting the number of tuning-elements in the fine bank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PLL uses a tunable oscillator with tuning-elements to control output frequency, then the PLL can maintain a predetermined relationship with the reference signal, but environmental changes (temperature and supply voltage drift) cause post-calibration drift and instability
Solution Approach 1:
The patent applies preliminary action by initializing the fine-tuning control code before calibration based on predicted temperature and supply voltage values. This pre-initialization sets the tuning-elements to an anticipated optimal state, allowing the PLL to compensate for environmental drift before it significantly impacts performance. The fine-tuning code is calculated in advance using predicted environmental conditions, preparing the oscillator for upcoming drift compensation needs.
Solution Approach 2:
The patent changes the parameter of the fine-tuning control code based on environmental conditions. By adjusting the fine-tuning code according to predicted temperature and supply voltage values, the system dynamically modifies the oscillator's tuning parameters to compensate for drift. This parameter adjustment allows the PLL to maintain frequency stability despite environmental variations affecting the hardware.
2Reliability
If the PLL adjusts the number of tuning-elements to compensate for drift, then frequency stability is maintained, but the complexity of control increases
Solution Approach 1:
The patent manages complexity by systematically changing the fine-tuning control code parameter based on environmental predictions. Rather than implementing complex real-time adjustment mechanisms, the system uses predicted temperature and supply voltage values to calculate and set the appropriate fine-tuning code in advance. This approach maintains frequency stability through parameter adjustment while avoiding the need for complex dynamic control circuitry.
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.