VCO Tuning Range Extension Using MOS Parasitic Capacitance

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Solution Overview

Problem

Conventional techniques for extending the tuning range of voltage-controlled oscillators (VCOs) in phase-locked loops often result in degradation of circuit quality factor and phase noise performance.

Innovation Solution

Utilizing parasitic capacitance of semiconductor devices in the VCO circuit, specifically by controlling the capacitance of MOS devices, to extend the tuning range without degrading VCO circuit performance, through signal conditioning that includes frequency filtering and analog or digital processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional techniques are used to enlarge the tuning range of a VCO, then the tuning range is extended, but the circuit quality factor deteriorates leading to degraded phase noise performance

Engineering Contradiction:

Improvetuning rangeVSAvoidphase noise performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent converts the harmful parasitic capacitance of MOS devices into a beneficial resource for extending the tuning range. By applying reverse bias voltage to the bulk terminals of the MOS devices, the parasitic drain-to-bulk capacitance is modulated to provide additional capacitance variation, thereby extending the VCO tuning range without degrading phase noise performance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the electrical parameters of the MOS devices by applying reverse bias voltage to the bulk terminals. This modifies the depletion region width and consequently the parasitic capacitance, enabling extended tuning range. The signal conditioning circuit processes the tuning voltage to generate appropriate bulk bias voltages that optimize the capacitance modulation.

Inventive Principle:

Principle #35Parameter changes

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 approach allows for an extended tuning range of VCOs with minimal performance degradation, maintaining phase noise performance and operational frequency.

Implementation Method 1

the parasitic capacitance of semiconductor devices in the VCO circuit may be utilized to extend the tuning range of a VCO without significant degradation of VCO circuit performance

Methodology Applied

Scientific EffectParasitic capacitance: Parasitic Capacitance

Implementation Method 2

The frequency of the output signal may be controlled by controlling a capacitance of at least one voltage-variable capacitance with the first signal

Methodology Applied

Scientific EffectVoltage-variable capacitance: Capacitance

Data Source

PatentUS10333465B2VCO tuning range extension using parasitic diode capacitance control

Publication Date: 2019.06.25 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Embodiments of methods and apparatuses may provide the capability to extend the tuning range of a VCO in a way that does not degrade VCO circuit performance. For example, the parasitic capacitance of semiconductor devices in the VCO circuit may be utilized to extend the tuning range of a VCO without significant degradation of VCO circuit performance. For example, in an embodiment, a method voltage-control of an oscillator may comprise receiving a first signal for control of a frequency of an output signal from the oscillator, deriving a second signal from the first signal, controlling the frequency of the output signal from the oscillator using the first signal, and extending a frequency range of the oscillator using the second signal.