Piezoelectric Oscillator Frequency Range and Stability Control
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Solution Overview
Problem
Existing piezoelectric oscillators face challenges in covering a wide range of frequencies using a single IC, leading to increased costs and instability due to high initial costs of IC fabrication and temperature sensitivity, as they require high initial costs and are not cost-effective for mass production.
Innovation Solution
A piezoelectric oscillator design incorporating a piezoelectric resonator, an oscillation circuit with a variable resistance circuit and a constant current circuit, including a current mirror circuit and a control circuit to adjust the output current and resistance values, allowing for a single IC to operate across a wide frequency range and maintain stability across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a piezoelectric resonator is downsized to increase frequency range coverage, then the frequency range is widened, but the effective resistance increases and frequency dips are produced
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the collector current and collector potential of the oscillation transistor based on the oscillation frequency. The control circuit modifies operating parameters (current and voltage) to compensate for the increased effective resistance and frequency dips caused by using a downsized piezoelectric resonator, thereby maintaining oscillation stability across a wide frequency range.
2Loss of time
If the collector current is increased to shorten oscillation starting-up time, then the starting-up time is reduced, but the power consumption increases
Solution Approach 1:
The patent implements dynamics by making the collector current and collector potential variable rather than fixed. The control circuit dynamically adjusts these parameters based on the oscillation frequency, allowing the system to optimize between fast startup (higher current) and low power consumption (lower current) depending on the operating conditions, thereby resolving the contradiction between startup time and power consumption.
3Device complexity
If a single IC is used to cover wide frequency range, then the device complexity is reduced, but the manufacturing precision requirements increase due to temperature sensitivity
Solution Approach 1:
The patent applies feedback by using a control circuit that monitors the oscillation frequency and adjusts the collector current and collector potential accordingly. This feedback mechanism compensates for temperature variations and manufacturing tolerances, maintaining frequency stability despite the use of a single IC design that integrates multiple functions.
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
Enables a single IC to be used across a wide range of frequencies, reducing costs and improving noise characteristics by setting adequate collector potentials and output currents, thus stabilizing the oscillator's operation and reducing production costs.
Implementation Method 1
a piezoelectric resonator
Implementation Method 2
a first current mirror circuit
Data Source
AI summary
A piezoelectric oscillator includes: a piezoelectric resonator; an oscillation circuit including a variable resistance circuit and a transistor for oscillation; a constant current circuit, the constant current circuit including a first current mirror circuit, and a current control circuit having an output terminal and controlling a current flowing in the first current circuit so as to enable an output current of the constant current circuit to be adjusted, the output terminal of the first current mirror circuit being coupled to at least one of a collector and a base of the transistor for oscillation with the variable resistance circuit; and a control circuit coupled to the current control circuit and the variable resistance circuit, the control circuit controlling the current control circuit and a resistance value of the variable resistance circuit.