Oscillator Thermal Sensor Layout for Faster Frequency Correction
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Solution Overview
Problem
Conventional oscillators experience a delay in correcting frequency temperature characteristics due to the inability to promptly follow the temperature change of the crystal vibration plate, leading to hysteresis in frequency temperature characteristics.
Innovation Solution
A surface-mount type oscillator with a temperature sensor disposed closer to the metal cover, using a copper foil for thermal conduction to measure ambient temperature, and a transient thermal response calculation unit to estimate the crystal vibration plate's temperature, calculating a frequency correction value to prevent delays and reduce hysteresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermistor is disposed in the vicinity of the reference crystal oscillator to measure temperature, then the frequency temperature characteristics can be corrected, but the temperature measurement follows the crystal vibration plate temperature with a delay, causing hysteresis in frequency correction
Solution Approach 1:
The patent introduces a copper foil as a thermal intermediary between the ambient environment and the temperature sensor. The copper foil rapidly conducts ambient temperature changes to the sensor, enabling the sensor to measure temperature changes before they affect the crystal vibration plate, thus eliminating measurement delay and hysteresis in frequency correction
Solution Approach 2:
The temperature sensor is positioned to measure ambient temperature through the copper foil before the temperature changes are transmitted to the crystal vibration plate. This preliminary measurement allows the system to proactively adjust frequency correction before temperature drift occurs, preventing hysteresis rather than correcting it after the fact
2Measurement precision
If the temperature sensor is placed close to the crystal vibration plate to measure its temperature, then direct temperature measurement is achieved, but the sensor itself experiences thermal conduction delay from the ambient temperature
Solution Approach 1:
The copper foil acts as a thermal intermediary that preferentially conducts ambient temperature to the sensor before it reaches the crystal vibration plate. This creates a thermal measurement path that is faster than the crystal's thermal response, allowing the sensor to detect temperature changes ahead of time without being thermally coupled directly to the crystal
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
Prevents delays in frequency temperature correction and reduces hysteresis by accurately measuring ambient temperature before the crystal vibration plate changes, ensuring timely frequency adjustments.
Implementation Method 1
measuring a temperature via a copper foil for thermal conduction soldered to the metal cover
Data Source
AI summary
An oscillator capable of preventing a delay in correction of frequency temperature characteristics by measuring an ambient temperature before a temperature of a crystal vibration plate is changed and capable of reducing hysteresis of the frequency temperature characteristics.A surface-mount type oscillator provided with an ambient temperature measuring sensor 15 that measures a temperature for correcting frequency temperature characteristics, on a substrate 1 on which a plurality of circuits are mounted, in which the ambient temperature measuring sensor 15 is disposed closer to a metal cover 2 than a reference crystal oscillator 11 including a crystal vibration plate and other circuits, and measures a temperature via a copper foil 16 for thermal conduction that is soldered to the metal cover 2 by the soldered portion 17, and the measured temperature is used for correcting the frequency temperature characteristics.