OCXO Oscillation Circuit With Supply-Voltage Temperature Correction
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Solution Overview
Problem
Existing oven controlled crystal oscillators (OCXO) face reduced accuracy in temperature compensation and frequency stability due to fluctuations in power supply voltage, which affect the heat generated by integrated circuits and subsequently the detected temperature values.
Innovation Solution
An oscillation circuit that includes a digital signal processing circuit to generate a temperature compensation code by using a first polynomial with a correction code added to the temperature code, and a second polynomial with the power supply voltage code as a variable, allowing for high-order expressions and digital filter processing to correct for frequency-temperature characteristics and power supply voltage fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power supply voltage is supplied to integrated circuit, then temperature sensor can operate and detect temperature, but heat generated by integrated circuit fluctuates with power supply voltage causing temperature detection accuracy to deteriorate
Solution Approach 1:
The patent introduces a correction code as an intermediary element that mediates between the power supply voltage fluctuations and the temperature detection accuracy. The correction code is generated based on the power supply voltage code through polynomial processing, and then added to the temperature code to compensate for the heat-induced measurement errors. This intermediary correction mechanism allows the system to maintain accurate temperature compensation despite power supply variations affecting the temperature sensor's operating environment.
Solution Approach 2:
The system implements feedback by continuously monitoring the power supply voltage through the power supply voltage code and using this information to generate real-time correction codes. The correction codes are fed back into the temperature compensation process by adding them to the temperature codes, creating a closed-loop system that actively compensates for power supply-induced errors in temperature measurement and compensation.
2Reliability
If digital signal processing circuit generates correction code using high-order polynomial, then frequency stability is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex analog compensation circuits with digital signal processing. Instead of using complex analog components and circuits to achieve frequency stability, the system uses digital polynomial processing to generate correction codes. This substitution of digital processing for analog mechanisms allows high-order polynomial calculations to be performed with relatively simple digital logic, achieving frequency stability without proportionally increasing device complexity.
Solution Approach 2:
The system changes the parameter representation from analog continuous values to digital discrete codes. By converting power supply voltage and temperature measurements into digital codes and processing them through polynomial equations, the system achieves precise frequency control through parameter manipulation in the digital domain, which is more efficient and less complex than equivalent analog implementations.
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 solution enhances the accuracy of temperature compensation and frequency stability by effectively correcting for fluctuations in power supply voltage, reducing the likelihood of frequency accuracy being lowered, and allowing for a more compact integrated circuit design.
Implementation Method 1
a temperature sensing element that outputs a temperature detection signal
Implementation Method 2
an oven controlled crystal oscillator (OCXO) including a heating element that heats a resonator
Data Source
AI summary
An oscillator circuit includes a circuit for oscillation that oscillates a resonator and outputs an oscillation signal, a temperature sensing element that outputs a temperature detection signal, an analog/digital conversion circuit that converts the temperature detection signal into a temperature code which is a digital signal and converts a power supply voltage into a power supply voltage code which is a digital signal, and a digital signal processing circuit that generates a correction code based on the power supply voltage code, and generates a temperature compensation code for compensating frequency-temperature characteristics of the oscillation signal based on the temperature code and the correction code.