Autotransformer Local Oscillator Without Buffer Amplifier
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Solution Overview
Problem
Conventional local oscillators in transceiver systems face challenges in balancing energy consumption, phase noise, and surface area occupation, with buffer amplifiers introducing variable gain and degrading signal duty cycle, and over-dimensioning these amplifiers leads to excessive energy consumption.
Innovation Solution
Incorporating an autotransformer with a primary inductive element and secondary inductive elements coupled to the frequency divider input terminals, eliminating the need for a buffer amplifier while maintaining low oscillation levels and suitable phase noise, and allowing for flexible circuit architecture with reduced surface area occupation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a buffer amplifier is used to isolate the LC resonator from the frequency divider and generate an amplified signal, then the frequency divider receives sufficient signal amplitude, but the buffer amplifier has variable gain sensitive to temperature and frequency, degrades the duty cycle of the input signal, and consumes excessive energy when over-dimensioned
Solution Approach 1:
The patent removes the buffer amplifier from the conventional local oscillator architecture. Instead of using a buffer amplifier to isolate the LC resonator and amplify the signal, the invention directly couples the LC resonator to the frequency divider through an inductive element, eliminating the component responsible for variable gain and excessive energy consumption.
Solution Approach 2:
The patent employs an asymmetric inductive coupling structure where the inductive element has different coupling coefficients to the LC resonator and the frequency divider. This asymmetric design allows the same inductive element to provide both isolation for the LC resonator and sufficient signal amplitude for the frequency divider, replacing the need for an active buffer amplifier.
2Reliability
If the buffer amplifier is over-dimensioned to reduce sensitivity to temperature and frequency variations, then gain stability improves, but energy consumption becomes excessive
Solution Approach 1:
The inductive element automatically adjusts its coupling characteristics based on the operating conditions, providing inherent gain stability without requiring an over-dimensioned buffer amplifier. The passive inductive coupling self-regulates the signal transmission, eliminating the need for excessive power consumption to achieve stability.
3Area of stationary object
If the frequency of the LC resonator is increased to reduce the surface area of the inductive element, then the surface area occupation decreases, but the coupling between the oscillator and the output signal increases
Solution Approach 1:
The patent segments the inductive coupling function into two distinct inductive elements: one for coupling the LC resonator and another for coupling the frequency divider output. This segmentation allows each inductive element to be optimized independently, enabling high frequency operation with reduced surface area while minimizing unwanted coupling through proper positioning and design of each segment.
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 configuration reduces energy consumption without compromising performance, maintains low phase noise, and allows for a more compact and efficient integrated circuit design by eliminating the need for a buffer amplifier and reducing conductive track length.
Implementation Method 1
an autotransformer including the first inductive element and two second inductive elements respectively coupled to the terminals of the first inductive element and to two output terminals of the autotransformer
Data Source
AI summary
A local oscillator device includes an oscillator module including a first inductive element and a capacitive element coupled in parallel with the inductive element. A frequency divider is coupled to the oscillator module for delivering a local oscillator signal. The local oscillator device includes an autotransformer including the first inductive element and two second inductive elements respectively coupled to the terminals of the first inductive element and to two output terminals of the autotransformer, the output terminals being further coupled to input terminals of the frequency divider.