Oscillation Device Constant Voltage Circuit Temperature Regulation
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Solution Overview
Problem
Conventional oscillation devices face a tradeoff between minimizing the difference in voltage response to temperature changes between constant voltage and oscillation stop voltage, leading to high consumption currents, typically ranging from 75 to 110 nA.
Innovation Solution
Incorporating a temperature characteristic regulation element into the constant voltage circuit, which includes a reference voltage circuit with a constant current source, a differential amplification circuit, and MOS transistors, to minimize the difference between the voltage responses and regulate the consumption current, thereby reducing the overall consumption current of the oscillation device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage output from the constant voltage circuit is set higher than the oscillation stop voltage to ensure operation in the temperature range, then the reliability is improved, but the consumption current increases
Solution Approach 1:
The patent makes the constant voltage output dynamic by continuously adjusting it according to temperature variations, ensuring the voltage remains just above the oscillation stop voltage across the temperature range (-40°C to 85°C) without being excessively high, thereby achieving reliable operation with minimal consumption current
Solution Approach 2:
The patent adjusts the threshold voltages of the transistors (PMOS: 0.5V, NMOS: -0.5V) to optimize the constant voltage output characteristics, enabling the circuit to maintain reliable operation across temperature ranges while consuming only several nA of current
Data Source
AI summary
A constant voltage circuit which can realize a low consumption current, and a crystal oscillation circuit using the constant voltage circuit. The constant voltage circuit is provided with a temperature characteristic regulation element, in order to minimize a difference between a negative slope of a voltage response of a constant voltage to a temperature change and a negative slope of a voltage response of the smallest operation voltage that can oscillate in the crystal oscillation circuit to the temperature change, so that the consumption current of the crystal oscillation circuit is decreased. When the constant current generated by the constant voltage circuit is decreased, the consumption current of the constant voltage circuit is decreased, and the consumption current of the whole oscillation device is decreased.