Dual-Reference Oscillator Circuit for Stable Clock Duty Cycle
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Solution Overview
Problem
Existing oscillators generate clock signals with unstable duty cycles due to unbalanced first and second oscillation signals, leading to precision errors.
Innovation Solution
An oscillator design that includes a charge and discharge circuit generating oscillation signals using constant currents, an integrating circuit producing comparison voltages reflecting changes in these signals, and a comparison circuit generating clock signals based on these voltages, with a bias circuit providing reference voltages and currents to maintain precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reference voltage is used for comparing oscillation signals, then the circuit complexity is reduced, but the duty cycle precision deteriorates due to unbalanced oscillation signals
Solution Approach 1:
The single reference voltage is segmented into two separate reference voltages (first reference voltage and second reference voltage). Each oscillation signal is compared against its corresponding reference voltage independently, allowing for separate adjustment and optimization of each comparison threshold. This segmentation resolves the contradiction by enabling precise duty cycle control without requiring a complex multi-dimensional reference system.
Solution Approach 2:
Different reference voltages are applied to different comparison circuits based on their specific requirements. The first comparison circuit uses a first reference voltage optimized for the first oscillation signal, while the second comparison circuit uses a second reference voltage optimized for the second oscillation signal. This local optimization allows each comparison to be tuned independently, achieving high duty cycle precision without overall system complexity.
2Stability of the object's composition
If constant current sources are used for charging and discharging capacitors, then frequency stability is improved, but sensitivity to process deviations and environmental changes worsens
Solution Approach 1:
The patent implements feedback mechanisms where the comparison results are fed back to adjust the oscillation signals. The second oscillation signal is generated based on the comparison result of the first oscillation signal, creating a closed-loop system that automatically compensates for process deviations and environmental changes. This feedback approach maintains frequency stability while reducing sensitivity to external variations.
Solution Approach 2:
The patent dynamically adjusts operating parameters (such as reference voltages and current levels) based on comparison results and environmental conditions. By changing parameters adaptively rather than fixing them, the system maintains frequency stability across varying conditions while becoming less sensitive to process deviations and environmental changes.
Data Source
AI summary
The present disclosure relates to an oscillator including a charge and discharge circuit which generates a first oscillation signal according to a clock signal using a first constant current and a second oscillation signal according to an inverted clock signal using a second constant current, an integrating circuit which generates a first comparison voltage reflecting an amount of change in the first oscillation signal based on a comparison reference voltage and a second comparison voltage reflecting an amount of change in the second oscillation signal based on the comparison reference voltage, and a comparison circuit which generates the clock signal and the inverted clock signal according to a result of comparison between the first oscillation signal and the first comparison voltage and a result of comparison between the second oscillation signal and the second comparison voltage.