Oscillator Amplitude Regulator With Dual Feedback Noise Control
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Solution Overview
Problem
High frequency generation circuits face challenges with increased power consumption, noise, and longer start-up times due to the need for accurate amplitude control across varying Q-values and PVT conditions, which existing negative feedback loops fail to address effectively without introducing noise or increasing power consumption.
Innovation Solution
A dual feedback path system is implemented, where a first feedback path provides continuous amplitude control and a second feedback path offers discrete control of amplitude regulating parameters, allowing the first feedback path to operate at reduced gain, thereby reducing power consumption and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a negative feedback loop with high gain is used to control oscillator amplitude, then amplitude control accuracy is improved, but noise is introduced into the oscillator core
Solution Approach 1:
The patent introduces an amplitude detector as an intermediary component that measures the oscillator output amplitude and converts it to a control signal. This mediator allows the feedback loop to control amplitude without directly coupling high-gain amplification to the oscillator core, thereby reducing noise injection while maintaining control accuracy.
Solution Approach 2:
The patent implements a negative feedback loop that continuously monitors the oscillator output amplitude through the detector and adjusts the oscillator core accordingly. This closed-loop feedback mechanism maintains accurate amplitude control while allowing optimization of the feedback path to minimize noise introduction.
2Object-generated harmful factors
If the loop gain of the negative feedback loop is increased to reduce AM noise, then AM noise is reduced, but power consumption increases and PM noise is not reduced
Solution Approach 1:
The patent replaces the traditional high-gain amplification approach with a detection and control signal generation approach. The amplitude detector converts amplitude information into a control signal that adjusts the oscillator core parameters, substituting direct high-gain amplification with a more efficient sensing and actuation mechanism that consumes less power.
3Object-generated harmful factors
If the bandwidth of the negative feedback loop is reduced to reduce noise, then noise is reduced, but startup time increases and filter size increases
Solution Approach 1:
The patent segments the feedback control into two independent paths: a wideband path for rapid transient response and startup, and a narrowband path for low-noise steady-state amplitude control. This segmentation allows each path to be optimized for its specific function without compromise.
Solution Approach 2:
The patent implements dynamic bandwidth adjustment where the feedback loop bandwidth is automatically adapted based on operating conditions. During startup and transient conditions, the bandwidth is widened for fast response; during steady-state operation, the bandwidth is narrowed to minimize noise, achieving both fast startup and low noise performance.
Data Source
AI summary
An electronic device comprises a first feedback circuit operatively connected to an amplitude detector and a first control input of an oscillator. The first feedback circuit is configured to control an amplitude of an output of the oscillator by continuously applying a first control signal to the first control input in response to an amplitude detected by the amplitude detector. The electronic device further comprises a second feedback circuit operatively connected to the amplitude detector and a second control input of the oscillator. The second feedback circuit is configured to modify one or more amplitude regulating parameters of the oscillator by providing a second control signal in response to the amplitude being beyond an upper or lower amplitude threshold, and refrain from modifying the one or more amplitude regulating parameters when the amplitude is within the upper and lower amplitude thresholds.