Internal Oscillator Synchronization for Stable Frequency Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated circuit internal oscillators face challenges in maintaining precise frequency accuracy over varying operating temperatures and voltages, leading to deviations in clock frequency calibration.
Innovation Solution
An integrated circuit device with a digital processor, clock oscillator, counter, frequency adjustment controller, and oscillator tuning circuit that automatically synchronizes the internal clock oscillator to an external frequency reference by adjusting its frequency based on comparisons between counted periods and a reference count, ensuring stability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the internal clock oscillator frequency is calibrated at factory for specific operating conditions, then the frequency accuracy is improved at calibration conditions, but the frequency accuracy deteriorates when operating temperature and voltage deviate from calibration conditions
Solution Approach 1:
The patent implements a feedback mechanism where the internal clock oscillator frequency is continuously monitored and compared against a reference frequency. A frequency adjustment controller receives feedback about frequency deviations and automatically adjusts the oscillator frequency by controlling tuning elements, thereby maintaining accurate frequency despite temperature and voltage variations
Solution Approach 2:
The system performs self-correction of frequency drift through automatic frequency adjustment. The frequency adjustment controller continuously monitors the oscillator output and autonomously adjusts tuning elements to compensate for environmental variations, enabling the system to maintain frequency accuracy without external intervention
2Measurement precision
If manual frequency calibration is performed at factory, then the initial frequency accuracy is improved, but long-term frequency stability deteriorates due to environmental variations
Solution Approach 1:
A continuous feedback loop compares the internal oscillator frequency with a reference frequency and automatically adjusts the oscillator to compensate for drift, ensuring long-term frequency stability without requiring manual recalibration
Solution Approach 2:
The system pre-establishes frequency adjustment capabilities through factory calibration of the reference frequency and configures the frequency adjustment controller to automatically compensate for future environmental variations, preventing frequency drift before it occurs
3Device complexity
If no frequency adjustment mechanism is used, then the device complexity is reduced, but the frequency accuracy deteriorates under varying operating conditions
Solution Approach 1:
The patent introduces a feedback-based frequency adjustment system that automatically monitors and corrects oscillator frequency deviations, maintaining high frequency accuracy without requiring complex manual calibration procedures or multiple oscillators
Solution Approach 2:
The system dynamically adjusts oscillator parameters through electronic control of tuning elements, allowing frequency compensation for environmental variations without changing the physical structure or adding significant complexity to the oscillator design
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An internal integrated circuit clock oscillator is automatically synchronized to an external frequency reference by counting the number of periods of the internal clock oscillator (hereinafter "count") that occur within a period of a lower frequency external frequency reference then comparing the count to the reference count. When the reference count is greater than the count, the frequency of the internal clock oscillator is increased. When the reference count is less than the count, the frequency of the internal clock oscillator is decreased. When the reference count and the count are substantially the same, the frequency of the internal clock oscillator is not changed.