Floating-Comparator Relaxation Oscillator With Lower Noise
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Solution Overview
Problem
Relaxation oscillators suffer from high phase noise at high frequency offsets and poor performance due to increased power consumption and noise from common mode feedback generation circuits, leading to increased circuit area and costs.
Innovation Solution
A relaxation oscillator design that uses a floating amplifier comparator, eliminating the need for an additional common mode feedback generation circuit, with a signal generation module generating voltage signals that control the oscillation module to output oscillation signals, achieving signal amplification and reducing noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional relaxation oscillator design with common mode feedback generation circuit is used, then oscillation signal can be generated, but power consumption increases and noise increases
Solution Approach 1:
The patent removes the common mode feedback generation circuit from the oscillator design. By extracting this unnecessary component, the invention eliminates the source of increased power consumption and noise while maintaining the core oscillation functionality through the differential amplifier and capacitor charging/discharging mechanism.
Solution Approach 2:
The differential amplifier automatically maintains common mode voltage stability through its inherent differential operation without requiring external feedback circuits. The circuit serves itself by using the natural properties of differential amplification to reject common mode signals, eliminating the need for additional power-consuming feedback generation components.
2Reliability
If traditional relaxation oscillator design with common mode feedback generation circuit is used, then oscillation signal can be generated, but circuit area increases
Solution Approach 1:
The patent extracts and removes the common mode feedback generation circuit from the design, directly reducing the occupied circuit area while preserving the essential oscillation signal generation capability through the simplified differential amplifier-based architecture.
3Stability of the object's composition
If relaxation oscillator is used, then good long-term frequency stability is achieved, but phase noise at high frequency offset is higher than ring oscillator
Solution Approach 1:
The patent changes the operating parameters of the relaxation oscillator by using a differential amplifier with optimized gain and bandwidth characteristics. This parameter optimization allows the circuit to maintain good long-term frequency stability while reducing phase noise at high frequency offsets through improved signal-to-noise ratio in the differential operation.
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
This design results in smaller occupied area, lower power consumption, less noise, and improved performance compared to traditional relaxation oscillators, with the ability to maintain phase noise robustness across various process, voltage, and temperature conditions.
Implementation Method 1
a capacitor, wherein, in a pre-charging stage of the work cycle, the first switch and the second switch are turned on to charge the capacitor
Implementation Method 2
the comparison unit compares the first voltage signal and the second voltage signal with the threshold voltage, respectively, and outputs the first oscillation signal and the second oscillation signal based on a result of the comparing
Data Source
AI summary
The present disclosure relates to a relaxation oscillator, an integrated circuit and an electronic apparatus, the relaxation oscillator comprising a first signal generation module and an oscillation module configured to output a first oscillation signal and a second oscillation signal, the first oscillation signal and the second oscillation signal being opposite in phase, the oscillation module comprising a first switch, a second switch, a capacitor, and a comparison unit. The oscillation module according to the disclosed embodiment using a floating amplifier to implement a comparator, where in a pre-charging stage, the first switch and the second switch are turned on to charge the capacitor, and a common mode of the first oscillation signal and the second oscillation signal is determined; in a comparing stage, the first switch and the second switch are turned off to output the oscillation signal. The embodiment of the present disclosure eliminates the need to provide an additional common mode feedback generation circuit, and does not require an increase in power consumption, achieving the advantages of smaller occupied area, lower power consumption, less noise, and better performance as compared with a relaxation oscillator of the related art.