Variable Capacitance Oscillator Control for Fine Temperature Compensation

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Solution Overview

Problem

Existing oscillator technologies face reduced accuracy in temperature compensation due to insufficient capacitance switching resolution, which increases frequency deviation, and attempting to improve resolution by reducing capacitance element values leads to increased variation in capacitance values, compromising accuracy.

Innovation Solution

A circuit device with a variable capacitance circuit and a processing circuit that switches capacitance control data in a time-division manner based on temperature data, allowing for finer increments in capacitance adjustments without reducing the capacitance element values, thereby improving resolution and accuracy of temperature compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the capacitance value of the capacitance element is reduced to increase the resolution of capacitance switching, then the resolution of capacitance switching is improved, but the variation in capacitance value increases which reduces the accuracy of temperature compensation

Engineering Contradiction:

Improveresolution of capacitance switchingVSAvoidaccuracy of temperature compensation

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent applies periodic action by switching capacitance control data in a time-division manner between first and second capacitance values. The processing circuit switches between different capacitance control data corresponding to different temperature data at different time periods, achieving effective capacitance adjustment without reducing the physical capacitance element values. This temporal switching mechanism resolves the contradiction by providing fine resolution through time-based control rather than through smaller capacitance values.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If the capacitance value of the capacitance element is reduced to increase the resolution of capacitance switching, then the resolution of capacitance switching is improved, but the frequency deviation of the oscillation frequency may increase

Engineering Contradiction:

Improveresolution of capacitance switchingVSAvoidfrequency deviation

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The processing circuit implements periodic switching between different capacitance control data sets that correspond to different temperature conditions. By switching between first and second capacitance control data in a time-division manner, the system achieves fine resolution capacitance adjustment without using smaller capacitance elements, thereby avoiding increased frequency deviation while maintaining high resolution control.

Inventive Principle:

Principle #19Periodic action

3Device complexity

If a small number of capacitance elements are used with same capacitance value to perform precise control, then the device complexity is reduced, but the resolution of capacitance switching becomes insufficient

Engineering Contradiction:

Improvenumber of capacitance elementsVSAvoidresolution of capacitance switching

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by introducing time-based switching of capacitance control data. Instead of using multiple capacitance elements with different values, the system dynamically switches between different capacitance control data sets corresponding to different temperature conditions. This temporal dimension adds control resolution without increasing the number of physical capacitance elements, resolving the contradiction between device simplicity and control precision.

Inventive Principle:

Principle #15Dynamics

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 enhances the accuracy of temperature compensation by allowing for precise capacitance adjustments between defined increments, maintaining high accuracy without increasing capacitance variation, thus stabilizing oscillation frequency across temperature fluctuations.

Implementation Method 1

temperature data obtained by A/D converting a temperature detection voltage from a temperature sensor

Methodology Applied

Scientific EffectTemperature detection:

Implementation Method 2

an oscillation circuit that includes a variable capacitance circuit configured by a capacitor array and oscillates at an oscillation frequency corresponding to a capacitance value of the variable capacitance circuit

Methodology Applied

Scientific EffectCapacitance-frequency relationship:

Data Source

PatentUS11038509B2Circuit device, oscillator, real-time clock device, electronic device, and vehicle

Publication Date: 2021.06.15 SEIKO EPSON CORP

AI summary

A circuit device includes an oscillation circuit and a processing circuit. The oscillation circuit includes a variable capacitance circuit configured by a capacitor array and oscillates at an oscillation frequency corresponding to the capacitance value of the variable capacitance circuit. First temperature data and second temperature data subsequent to the first temperature data are input to the processing circuit as temperature data. In the period between the start of the capacitance control based on the first temperature data and the start of the capacitance control based on the second temperature data, the processing circuit switches the first capacitance control data corresponding to the first temperature data and the second capacitance control data different from the first capacitance control data in a time-division manner to be output to the variable capacitance circuit.