Electronic Oscillator with Independent Load Capacitance Tuning

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Solution Overview

Problem

Existing electronic oscillators face challenges in achieving precise adjustment of oscillation frequency, particularly when using quartz and MEMS resonators, as the required precision in load capacitance adjustment leads to increased variations in oscillation frequency.

Innovation Solution

An electronic oscillator design that includes a resonator coupled in parallel to an active circuit, with two electrodes connected to distinct variable capacitances forming the load capacitance, and a control device to independently control the values of these variable capacitances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of capacitors in the banks is increased to achieve greater precision in adjusting the load capacitance value, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improveprecision in adjusting load capacitance valueVSAvoidnumber of capacitors in the banks
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the load capacitance adjustment into two independent parts: a first variable capacitance (C1) and a second variable capacitance (C2). Each capacitance is controlled by separate control signals, allowing independent adjustment. This segmentation enables precise frequency tuning without requiring a large number of capacitors in a single bank, as each bank can use fewer capacitors while collectively providing fine adjustment resolution.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the value of the load capacitance is reduced to achieve finer frequency adjustment, then the measurement precision is improved, but the oscillation stability deteriorates due to greater frequency variations

Engineering Contradiction:
Improvefrequency adjustment precisionVSAvoidoscillation frequency stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

By splitting the load capacitance into two independently controllable variable capacitances, the patent enables differential adjustment where C1 and C2 can be tuned separately. This allows the total load capacitance to be optimized for stability while still achieving fine frequency resolution through the independent control of each capacitance element, avoiding the need to reduce overall capacitance value which would harm stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the control parameters by introducing two independent control signals instead of a single control signal. This allows the system to adjust frequency by varying the difference between C1 and C2 while maintaining a stable total capacitance level, thereby achieving fine frequency resolution without compromising oscillation stability.

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 design allows for precise and independent adjustment of the load capacitance values, enabling finer control over the oscillation frequency with reduced variations, thus enhancing the precision and stability of the oscillator.

Implementation Method 1

Electronic oscillators using quartz resonators are widely used... The high quality factor and low intrinsic electrical resistance of quartz resonators allow them to maintain stable oscillation

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the resonator comprising two electrodes coupled to distinct variable capacitances forming a load capacitance of the electronic oscillator

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4557607A1Electronic oscillator with independent controls of variable capacities
Publication Date: 2025.05.21 STMICROELECTRONICS INT NV
  • EP4557607A1 patent drawingFigure 1~2
  • EP4557607A1 patent drawingFigure 3~5
  • EP4557607A1 patent drawingFigure 6~7

AI summary

The present description relates to an electronic oscillator (100) comprising a resonator (102) coupled in parallel to at least one active circuit (104), the resonator comprising two electrodes (110, 112) coupled to separate variable capacitors (116, 118) forming a load capacitor of the electronic oscillator, and a control device (148) configured to independently control the values ​​of the variable capacitors.