Tunable Oscillator Bias Circuit for Stable Frequency Compensation
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Solution Overview
Problem
Conventional oscillators are large, expensive, and inflexible, with manufacturing costs and size limitations due to the inclusion of band gap reference circuits, and they cannot adjust oscillation frequency without adding a frequency variable circuit, which increases costs and size.
Innovation Solution
A tunable oscillator design incorporating a current bias circuit, a variable voltage bias circuit, an oscillation signal generator circuit, and a switching control circuit that generates a frequency-variable oscillation signal based on a bias voltage, allowing for stable frequency adjustment without a band gap reference circuit, using current mirrors, self-bias circuits, and variable resistor circuits to compensate for temperature and power voltage fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a band gap reference circuit is used to generate temperature-independent voltage and current, then the oscillation signal period becomes independent of temperature, but the oscillator size increases and manufacturing cost increases
Solution Approach 1:
The patent extracts the essential function of temperature compensation from the complex band gap reference circuit. Instead of using the full band gap circuit, the invention uses a simplified approach with a temperature compensation circuit that generates a compensation current based on temperature variations, which is then combined with the bias current to achieve temperature-independent oscillation frequency without requiring the expensive and large band gap reference circuit
Solution Approach 2:
The patent creates a simplified copy of the temperature compensation function. Rather than implementing the complete band gap reference circuit, the invention replicates the essential temperature compensation effect using a dedicated temperature compensation circuit that generates proportional compensation currents, achieving the same temperature independence goal with reduced complexity and size
2Reliability
If a band gap reference circuit is used to generate temperature-independent voltage and current, then the oscillation signal period becomes independent of temperature, but the manufacturing cost increases
Solution Approach 1:
The patent extracts the essential function of temperature compensation from the complex band gap reference circuit. Instead of using the full band gap circuit, the invention uses a simplified approach with a temperature compensation circuit that generates a compensation current based on temperature variations, which is then combined with the bias current to achieve temperature-independent oscillation frequency without requiring the expensive and large band gap reference circuit
Solution Approach 2:
The patent replaces the expensive band gap reference circuit with a cheaper alternative implementation. The temperature compensation circuit uses simpler, lower-cost components that can be easily manufactured, achieving the same temperature compensation function at reduced manufacturing cost
3Adaptability or versatility
If a frequency variable circuit is added to adjust oscillation frequency, then the oscillation frequency can be changed, but the manufacturing cost increases and the oscillator size increases
Solution Approach 1:
The patent implements dynamic frequency adjustment by making the oscillation frequency dependent on a controllable parameter. The bias current, which determines the oscillation frequency, is made adjustable through a current control circuit that can vary the bias current based on control signals, enabling frequency tuning without adding separate frequency variable circuits
Solution Approach 2:
The patent integrates the frequency adjustment function into the existing bias circuitry. The current control circuit serves multiple functions: it provides the bias current for oscillation, enables frequency tuning through control signals, and works in conjunction with the temperature compensation circuit. This multi-functionality eliminates the need for separate frequency variable circuits
4Adaptability or versatility
If a frequency variable circuit is added to adjust oscillation frequency, then the oscillation frequency can be changed, but the manufacturing cost increases
Solution Approach 1:
The patent implements dynamic frequency adjustment by making the oscillation frequency dependent on a controllable parameter. The bias current, which determines the oscillation frequency, is made adjustable through a current control circuit that can vary the bias current based on control signals, enabling frequency tuning without adding separate frequency variable circuits
Solution Approach 2:
The patent integrates the frequency adjustment function into the existing bias circuitry. The current control circuit serves multiple functions: it provides the bias current for oscillation, enables frequency tuning through control signals, and works in conjunction with the temperature compensation circuit. This multi-functionality eliminates the need for separate frequency variable circuits
Data Source
AI summary
A tunable oscillator includes a current bias circuit configured to generate a reference bias current, a variable voltage bias circuit configured to receive the reference bias current and generate a bias voltage varied based on a voltage control signal, an oscillation signal generator circuit configured to generate an oscillation signal based on the reference bias current and a switching control signal, and a switching control circuit configured to generate the switching control signal based on the bias voltage and the oscillation signal. A frequency of the oscillation signal is varied based on a magnitude of the bias voltage.