Transformer-Coupled Dual-Mode Oscillator for Low Phase Noise
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Solution Overview
Problem
Existing dual-mode oscillators provide wide-band oscillation signals but suffer from poor phase noise performance, limiting the performance of wireless communications systems.
Innovation Solution
A dual-mode oscillator design incorporating two transformer-coupled oscillators and a mode switching circuit, where the drain of one MOS transistor is connected to the gate of another through a step-up transformer, improving phase noise performance by increasing gate voltage swing without raising supply voltage, and a multi-phase oscillator configuration using a Mobius loop connection of dual-mode oscillators and multi-phase coupled circuits to generate multiple phases and enhance phase noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing dual-mode oscillator design with two LC oscillators and mode switching circuit is used, then wide-band oscillation signals can be provided, but phase noise performance deteriorates
Solution Approach 1:
A step-up transformer is introduced as an intermediary component between the first and second MOS transistors. The transformer couples the drain of the first transistor to the gate of the second transistor, enabling magnetic coupling that transfers energy efficiently while providing galvanic isolation. This intermediary structure allows the oscillators to operate in both in-phase and reverse-phase modes with improved phase noise performance, as the transformer's magnetic coupling reduces noise while maintaining the wide frequency range capability through mode switching.
2Reliability
If gate voltage swing is increased to improve phase noise performance, then supply voltage must be increased, but this increases power consumption
Solution Approach 1:
The patent replaces the direct electrical connection (mechanical/electrical system) between transistors with a magnetic coupling system using a step-up transformer. Instead of increasing supply voltage to achieve higher gate voltage swing, the transformer's magnetic field coupling amplifies the voltage swing through electromagnetic induction. The transformer steps up the voltage from the first transistor's drain to the second transistor's gate, achieving higher gate voltage swing without proportionally increasing supply voltage, thus improving phase noise performance while controlling power consumption.
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
The solution achieves improved phase noise performance and wider frequency ranges while maintaining low power consumption, effectively addressing the limitations of existing dual-mode oscillators in wireless communications systems.
Implementation Method 1
a drain of a first MOS transistor in each transformer-coupled oscillator is connected to a gate of a second MOS transistor through a step-up transformer, so that a larger gate voltage swing is obtained without increasing a supply voltage of the oscillator
Implementation Method 2
Each LC oscillator includes a pair of transistors and an LC oscillation circuit. Two switch groups, that is, switches S1 and S2 and switches S3 and S4, in the mode switching circuit are alternately turned on, so that the two LC oscillators are in two different operating modes.
Data Source
AI summary
A dual-mode oscillator and a multi-phase oscillator includes a mode switching circuit to switch between two operating modes and obtain oscillation signals having two different bands. The dual-mode oscillator also includes two transformer-coupled oscillators and a step-up transformer in the transformer-coupled oscillators where the step-up transformer multiplies a drain voltage swing of a first MOS transistor and then injects a voltage signal to a gate of a second MOS transistor to obtain a larger gate voltage swing without increasing a supply voltage of the oscillator. The dual-mode oscillators are connected through multi-phase coupled circuits to form a Mobius loop.