Bulk-Controlled VCO Tuning for Wide PLL Range and Low Phase Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing phase lock loops (PLLs) face challenges in maintaining a wide frequency range and low phase noise due to frequency drift caused by temperature and fabrication process variations, which can lead to gain variation and affect other performance characteristics.
Innovation Solution
The implementation of a voltage controlled oscillator (VCO) circuit comprising at least one inductor, one varactor, and two transistors with parasitic diodes, where control voltages applied to the transistors' bulk terminals adjust the oscillation frequency, allowing for improved control and compensation for frequency drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If one large band or stitched digital bands are employed to cover a wide frequency range, then the frequency range is extended, but gain variation occurs and phase noise performance deteriorates
Solution Approach 1:
The VCO is divided into multiple sub-bands, each with its own set of transistors and varactors. Each sub-band operates independently to cover a specific frequency range, avoiding the gain variation and phase noise issues associated with using one large band or stitched bands. The segmentation allows each sub-band to be optimized for low phase noise while collectively covering a wide frequency range.
2Stability of the object's composition
If a large overlap between stitched bands is used to account for frequency drift, then frequency stability is improved, but tuning range and phase noise performance are affected
Solution Approach 1:
The VCO employs dynamic switching between multiple sub-bands based on the desired output frequency and environmental conditions. Each sub-band is dynamically activated or deactivated to maintain optimal performance across the full tuning range. This dynamic approach allows the system to adapt to frequency drift while maintaining wide tuning range and low phase noise, avoiding the need for large static overlap between bands.
3Ease of operation
If control voltage is applied to bulk terminals of transistors, then oscillation frequency can be adjusted, but frequency drift due to temperature and process variations occurs
Solution Approach 1:
The system incorporates frequency detection and feedback mechanisms that monitor the actual oscillation frequency and adjust the control voltage applied to the bulk terminals accordingly. This feedback loop compensates for frequency drift caused by temperature and process variations, maintaining stable frequency control while preserving the ease of operation provided by voltage-controlled tuning.
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 enables a PLL to maintain a stable frequency range and reduce phase noise by effectively controlling the VCO's oscillation frequency, enhancing the PLL's performance characteristics and adaptability to temperature and process variations.
Implementation Method 1
at least one varactor... application of a first control voltage to the first bulk terminal, application of a second control voltage to the second bulk terminal, or application of first and second control voltages to the first and second bulk terminals, respectively, is effective to change the oscillation frequency of the VCO
Implementation Method 2
the first transistor has a first bulk terminal and a first parasitic diode disposed between the first bulk terminal and the first transistor; wherein the second transistor has a second bulk terminal and a second parasitic diode disposed between the second bulk terminal and the second transistor; wherein application of a first control voltage to the first bulk terminal... is effective to change the oscillation frequency of the VCO
Data Source
AI summary
An electrical circuit includes: at least one inductor, at least one varactor, and at least two transistors, all of which electrically arranged to form a voltage controlled oscillator (VCO) having an oscillation frequency; wherein the at least two transistors includes a first transistor and a second transistor; wherein the first transistor has a first bulk terminal and a first parasitic diode disposed between the first bulk terminal and the first transistor; wherein the second transistor has a second bulk terminal and a second parasitic diode disposed between the second bulk terminal and the second transistor; wherein application of a first control voltage to the first bulk terminal, application of a second control voltage to the second bulk terminal, or application of first and second control voltages to the first and second bulk terminals, respectively, is effective to change the oscillation frequency of the VCO.