Auto-Ranging PLL Divider Control for Wider Frequency Range
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Solution Overview
Problem
Phase-locked loops (PLLs) have limited output frequency ranges due to fixed dividing factors, requiring additional calibration time and being inflexible with unknown reference signal frequencies, which restricts their operational flexibility and efficiency.
Innovation Solution
A phase-locked loop circuit with a controllable dividing factor, managed by a rangefinder circuit that adjusts the dividing factor based on operating characteristics, such as the reference signal, allowing for dynamic frequency adjustments within the oscillator's range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed dividing factor is used in the dividing circuit, then the PLL can be calibrated and tested during manufacturing, but the output frequency range is limited and additional test time is required
Solution Approach 1:
The patent applies the Dynamics principle by making the dividing factor dynamic and adjustable during operation. The state machine monitors the reference signal frequency and automatically switches between different dividing factors (e.g., first dividing factor for lower frequencies, second dividing factor for higher frequencies), allowing the PLL to adapt to a wider frequency range without requiring separate calibration for each frequency point.
Solution Approach 2:
The patent implements Parameter changes by varying the dividing factor based on the reference signal frequency. The system changes the dividing parameter dynamically - using a first dividing factor when the reference signal is below a threshold frequency, and a second dividing factor when it exceeds the threshold, thereby expanding the operational frequency range.
2Adaptability or versatility
If the dividing factor is configured during calibration, then the PLL operates within a specific frequency range, but it cannot adapt to unknown reference signal frequencies
Solution Approach 1:
The patent applies the Self-service principle through the state machine that automatically monitors the reference signal frequency and selects the appropriate dividing factor without external intervention. The system self-configures by comparing the reference signal frequency against threshold values and autonomously switching dividing factors, eliminating the need for manual calibration for different frequency scenarios.
Solution Approach 2:
The system uses Feedback by continuously monitoring the reference signal frequency and using this information to adjust the dividing factor. The state machine receives feedback about the current frequency conditions and automatically modifies the dividing parameter to maintain optimal operation across varying frequency ranges.
3Productivity
If a single dividing factor is used, then the circuit design is simple, but the operational frequency range is restricted
Solution Approach 1:
The patent appliesSegmentation by dividing the frequency operating range into multiple segments, each handled by a specific dividing factor. The state machine segments the frequency spectrum and assigns appropriate dividing factors to different segments, allowing the system to efficiently handle a broad frequency range by processing different frequency bands with optimized dividing parameters.
Data Source
AI summary
A phase locked loop circuit includes an oscillator, a dividing circuit coupled to the oscillator having a controllable dividing factor, and a rangefinder circuit coupled to the dividing circuit. The rangefinder circuit is configured to control the dividing factor in response to an operating characteristic of the phase-locked loop circuit.