Oscillator Capacitance Split for Temperature and Frequency Control
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Solution Overview
Problem
Existing voltage controlled oscillators face challenges in achieving both appropriate temperature compensation and frequency control of oscillation frequencies across a wide temperature range due to the limitations of variable capacitance circuits with positive capacitance characteristics.
Innovation Solution
Incorporating a circuit device with a first variable capacitance circuit having a positive capacitance change characteristic and a second variable capacitance circuit with a negative capacitance change characteristic, where the temperature compensation circuit supplies a temperature compensation voltage to the first variable capacitance circuit and the frequency control circuit supplies a frequency control voltage to the second variable capacitance circuit, allowing for effective temperature compensation and frequency control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If only variable capacitance circuits with positive capacitance characteristics are used, then the circuit structure is simple, but it is difficult to achieve both appropriate temperature compensation for oscillation frequency in a wide temperature range and control of oscillation frequency
Solution Approach 1:
The patent divides the variable capacitance control function into two separate circuits: a first variable capacitance circuit for temperature compensation and a second variable capacitance circuit for frequency control. This segmentation allows each circuit to be optimized for its specific function, enabling wide temperature compensation while maintaining frequency control capability
Solution Approach 2:
The patent assigns different capacitance characteristics to different circuits based on their functional requirements. The first variable capacitance circuit uses positive capacitance characteristics for temperature compensation, while the second variable capacitance circuit uses negative capacitance characteristics for frequency control, optimizing each part's properties for its specific purpose
2Device complexity
If variable capacitance circuits with positive characteristics are used for temperature compensation, then the circuit scale can be minimized, but frequency control by frequency control voltage becomes difficult
Solution Approach 1:
The patent separates temperature compensation and frequency control into distinct circuits with different capacitance characteristics. The second variable capacitance circuit with negative capacitance characteristics is specifically dedicated to frequency control, ensuring that frequency control voltage can effectively adjust oscillation frequency while the first circuit handles temperature compensation
Solution Approach 2:
The patent changes the capacitance characteristic parameter of the second variable capacitance circuit to have negative characteristics, which enables effective frequency control. This parameter change allows the circuit to respond appropriately to frequency control voltage while maintaining minimal circuit scale
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 configuration enables precise temperature compensation and frequency control across a wide temperature range, reducing the need for complex amplifier circuits and minimizing circuit scale while maintaining accurate oscillation frequency.
Implementation Method 1
a first variable capacitance circuit whose capacitance change characteristic with respect to a capacitance control voltage is a positive characteristic
Implementation Method 2
a second variable capacitance circuit whose capacitance change characteristic with respect to the capacitance control voltage is a negative characteristic
Implementation Method 3
based on a temperature detection result of a temperature sensor
Data Source
AI summary
A circuit device includes: an oscillation circuit configured to oscillate a resonator; a temperature compensation circuit configured to output a temperature compensation voltage for temperature compensating an oscillation frequency of the oscillation circuit, based on a temperature detection result of a temperature sensor; and a frequency control circuit configured to output a frequency control voltage for the oscillation frequency. The oscillation circuit includes a first variable capacitance circuit having a positive capacitance change characteristic with respect to a capacitance control voltage and a second variable capacitance circuit having a negative capacitance change characteristic with respect to the capacitance control voltage. The temperature compensation circuit supplies the temperature compensation voltage as the capacitance control voltage to the first variable capacitance circuit, and the frequency control circuit supplies the frequency control voltage as the capacitance control voltage to the second variable capacitance circuit.