Oscillator Correction Circuit Using Dual Temperature References
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Solution Overview
Problem
Oscillation circuits face challenges in maintaining frequency accuracy due to temperature-related errors in Band-Gap Reference (BGR) circuits and resistance temperature characteristics, leading to voltage and frequency errors.
Innovation Solution
An oscillation apparatus with a correction circuitry that includes first and second amplifiers to generate a fourth voltage, which corrects the oscillation frequency by amplifying differences between reference voltages with distinct temperature characteristics, thereby canceling out temperature-dependent voltage errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a BGR circuit is used to generate reference voltage, then the oscillation circuit can operate, but temperature-dependent voltage errors occur leading to frequency inaccuracies
Solution Approach 1:
The reference voltage generation is segmented into multiple independent voltage sources (first reference voltage and second reference voltage) with different temperature characteristics. Each voltage source is processed separately through dedicated amplifiers to generate correction signals, allowing independent optimization and compensation of temperature effects without interfering with the basic oscillation operation.
Solution Approach 2:
The patent implements feedback mechanisms where the first amplifier amplifies the difference between the first reference voltage and a first feedback voltage, and the second amplifier amplifies the difference between the second reference voltage and a second feedback voltage. These feedback loops continuously adjust the correction voltages to compensate for temperature-dependent errors, maintaining frequency accuracy while preserving reliable oscillation operation.
2Measurement precision
If temperature compensation is implemented using multiple reference voltages and amplifiers, then frequency accuracy improves, but device complexity increases
Solution Approach 1:
The first and second reference voltages serve multiple functions: they provide the basis for oscillation operation, generate correction signals for temperature compensation, and enable the amplifiers to produce correction voltages that adjust the oscillation frequency. This multi-functionality reduces the need for separate dedicated compensation circuits, thereby limiting the increase in device complexity while achieving improved frequency accuracy.
Solution Approach 2:
The patent changes the temperature characteristics parameter of the reference voltages by using two different voltage sources with distinct temperature behaviors. The amplifiers then adjust the correction voltages based on these parameter differences, enabling frequency accuracy improvement through parameter variation rather than through complex structural modifications.
Data Source
AI summary
An oscillation apparatus includes a correction circuitry including a first amplifier and a second amplifier, and an oscillation circuitry. The first amplifier amplifies a difference between a first voltage having a first temperature characteristic and a second voltage having a second temperature characteristic different from the first temperature characteristic to generate a third voltage having a third temperature characteristic different from both the first temperature characteristic and the second temperature characteristic. The second amplifier amplifies a difference between a sum of the second voltage and the third voltage, and, a feedback voltage, to generate a fourth voltage which corrects an oscillation frequency of an oscillation voltage. The oscillation circuitry outputs the oscillation voltage controlled in frequency based on the fourth voltage.