PLL Resonator Voltage Control for Wider Frequency Tuning
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Solution Overview
Problem
LC resonators in phase-locked loops (PLLs) have a narrow frequency variable range, making it difficult to adjust the PLL's operation frequency to match changing communication speeds, particularly in semiconductor integrated circuit devices, where a broad frequency range is needed for effective communication.
Innovation Solution
A resonator is supplied with voltage from a constant-voltage source, where the output voltage is adjusted by a voltage adjustment signal, allowing the resonator to output a clock signal with a frequency varied by changing capacitance in response to control signals, thereby expanding the oscillation frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an LC resonator is used as a voltage-controlled oscillator in the PLL, then the PLL can operate with stable frequency, but the frequency variable range is narrow and broadband frequency output is difficult
Solution Approach 1:
The patent changes the operating parameters of the LC resonator by adjusting the supply voltage from the constant-voltage source. By varying the voltage level, the resonant frequency of the LC circuit is shifted, enabling broadband frequency output while maintaining stable oscillation. This resolves the contradiction by allowing the same LC resonator to operate at different frequency points within a broad range.
Solution Approach 2:
The patent introduces dynamic control of the supply voltage to the LC resonator through a constant-voltage source that responds to control signals. This dynamic voltage adjustment enables the resonator to adapt its frequency in real-time, transforming a static frequency component into a dynamically adjustable one, thus expanding the frequency variable range while preserving stability.
2Ease of operation
If the reference clock frequency is adjusted to compensate for PLL operation, then slight adjustment of VCO variable range is achieved, but control of PLL output frequency by external signal is difficult
Solution Approach 1:
The patent introduces a constant-voltage source as an intermediary between the control signal and the LC resonator. This intermediary converts external control signals into precise voltage adjustments that directly affect the resonator's operating frequency. The mediator enables easy external control of the PLL output frequency while maintaining smooth adjustment of the VCO variable range.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides a resonator with a broad oscillation frequency range, enabling the PLL to adjust its lock frequency over a wide range, effectively addressing the limitations of traditional LC resonators.
Implementation Method 1
a resonator that outputs a clock signal having a frequency that is varied by varying capacitance in accordance with a received control signal
Implementation Method 2
a frequency of the clock signal is varied by voltage output from the constant-voltage source
Data Source
AI summary
A resonator is supplied with voltage from a constant-voltage source, and the constant-voltage source outputs output voltage adjusted by a voltage adjustment signal to the resonator. The resonator outputs a clock signal having a frequency varied by varying capacitance in accordance with a received control signal and a frequency adjustment signal, and a frequency of the clock signal is varied by voltage output from the constant-voltage source.