Bias-Controlled Oscillator Circuit for Temperature-Stable Frequency
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Solution Overview
Problem
Existing oscillators face challenges in maintaining accurate frequency stability against temperature and process variations, leading to complex and difficult-to-control circuits with many variables.
Innovation Solution
An oscillating device with a driving module and oscillating module, where the bias current is made proportional to the bias, allowing for simple compensation of temperature and process variations using a few calibration bits, and a voltage regulating circuit provides a stable power source to reduce the influence of power supply voltage on oscillating frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a quartz oscillator is used to achieve high frequency stability and accuracy, then the frequency error is extremely small and temperature influence is minimal, but the system cost increases and the product size increases due to the printed circuit board
Solution Approach 1:
The patent creates a built-in oscillator that copies the function of a quartz oscillator but with reduced complexity. The ring oscillator circuit replicates the frequency generation capability while eliminating the need for external quartz crystal components and associated circuitry, achieving a balance between accuracy and integration
Solution Approach 2:
The patent uses temperature compensation by changing the bias current parameter dynamically. The compensation circuit adjusts the bias current based on temperature variations to maintain stable oscillation frequency, allowing the built-in oscillator to achieve temperature stability comparable to quartz oscillators without the associated cost and size penalties
2Reliability
If temperature and process compensation circuits are added to maintain frequency stability, then the oscillating frequency remains stable under drifts, but the circuit becomes complicated and difficult to control due to too many variables
Solution Approach 1:
The patent merges the temperature compensation function with the oscillation generation function into a single integrated circuit. The compensation circuit and oscillating circuit share common components and control signals, eliminating the need for separate compensation modules and reducing the overall number of variables that need to be controlled
Solution Approach 2:
The patent implements a feedback mechanism where the oscillation frequency is monitored and the bias current is automatically adjusted based on detected frequency deviations. This closed-loop control simplifies the compensation process by using the oscillator's own output as the feedback signal, reducing the need for external temperature sensors and complex control logic
Data Source
AI summary
The present invention relates to an oscillating device, which comprises a driving module and an oscillating module. The driving module is used for producing a first driving voltage and a second driving voltage. The oscillating module comprises a first symmetric load circuit, a second symmetric load circuit, and a bias circuit. The first symmetric load circuit and the second symmetric load circuit produce a bias according to the first driving voltage. The bias circuit produces a bias current according to the second driving voltage. The oscillating module produces an oscillating signal according to the first driving voltage and the bias current, where the bias current is proportional to the bias. Thereby, by making the driving signal produced by driving module proportional to the bias of the oscillating module, simple compensation for temperature and process can be performed. Thereby, the frequency can be tuned using a few calibration bits.