Quadratic Temperature Compensation for VCO Frequency Stability

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Solution Overview

Problem

Existing RF signal oscillators, particularly voltage controlled oscillators (VCOs), face challenges in maintaining stable frequency due to temperature drift, which current compensation methods like phase locked loops (PLLs) or high Q resonators address at increased complexity and cost.

Innovation Solution

A quadratic extension component generates a quadratic control voltage, applied to the VCO's tuning port, providing second-order temperature compensation to mitigate frequency drift, using a combination of proportional to absolute temperature (PTAT) components and squaring circuitry to achieve precise frequency stabilization with reduced power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a phase locked loop (PLL) is used to compensate for temperature drift, then frequency stability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvefrequency stabilityVSAvoidcircuit complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential temperature compensation function from the complex PLL system by using a simplified quadratic extension component that directly adjusts the VCO tuning voltage based on temperature, eliminating the need for full PLL circuitry while maintaining frequency stability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the compensation approach from linear PLL control to quadratic temperature compensation by using squaring circuitry to generate a quadratic control voltage that more accurately compensates for the non-linear temperature drift characteristics of the VCO

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If high Q dielectric resonators with appropriate temperature coefficient are used, then frequency stability is improved, but cost and manufacturing effort increase

Engineering Contradiction:

Improvefrequency stabilityVSAvoidmanufacturing effort

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive high Q dielectric resonators with a cost-effective quadratic extension component made from standard semiconductor elements including squaring circuitry and PTAT current sources that can be manufactured using conventional CMOS processes

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Stability of the object's composition

If laser frequency centering is used, then frequency stability is improved, but cost and effort increase

Engineering Contradiction:

Improvefrequency centering precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent substitutes the mechanical/optical laser frequency centering process with an electrical quadratic compensation system that automatically adjusts the VCO frequency based on temperature, eliminating the need for expensive laser equipment and manual adjustment processes

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Stability of the object's composition

If additional compensation components are added to mitigate temperature drift, then frequency stability is improved, but power consumption increases

Engineering Contradiction:

Improvefrequency stabilityVSAvoidpower consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent implements a self-service temperature compensation system where the quadratic extension component automatically generates the appropriate control voltage based on temperature sensor input, eliminating the need for external control circuits and reducing overall power consumption

Inventive Principle:

Principle #25Self-service

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

The solution effectively maintains the VCO's operating frequency within narrow bandwidth requirements, reducing temperature drift to less than 0.1% of the operating frequency, enabling reliable operation in both pulsed and continuous wave modes without the need for additional costly components.

Implementation Method 1

providing second-order temperature compensation to mitigate frequency drift, using a combination of proportional to absolute temperature (PTAT) components and squaring circuitry

Methodology Applied

Scientific EffectProportional to absolute temperature (PTAT):

Data Source

PatentUS9748962B2Systems and methods for oscillators using quadratic temperature compensation

Publication Date: 2017.08.29 INFINEON TECHNOLOGIES AG

AI summary

A voltage controlled oscillator arrangement is disclosed. The arrangement includes a voltage controlled oscillator and a quadratic extension component. The voltage controlled oscillator has a tuning port. The tuning port is configured to select an operating frequency according to an applied voltage. The quadratic extension component is configured to generate a quadratic tuning voltage that as the applied voltage to the tuning port. The quadratic tuning voltage is generated according to a linear temperature compensation signal.