Tapped-Inductor Oscillator Circuit for Low-Noise, Low-Power VCOs
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Solution Overview
Problem
Conventional voltage controlled oscillators (VCOs) face challenges in meeting noise and power requirements as they shrink in size, leading to increased thermal noise due to lower quality factors and decreased inductor sizes, which are exacerbated by higher frequencies and lower supply voltages.
Innovation Solution
The oscillator circuit employs a tapped inductor design with symmetrical segments forming an 8-shaped physical loop, coupled by capacitors, and transconductance amplifiers with cross-coupled feedback to reduce phase noise and improve performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the inductor size is decreased to reduce VCO area, then the area requirement is met, but the quality factor decreases and thermal noise increases
Solution Approach 1:
The inductor is divided into multiple segments (first inductor segment, second inductor segment, third inductor segment) connected in series. This segmentation allows the total inductance to be achieved with smaller individual segments, reducing the overall area while maintaining the quality factor by optimizing the layout and reducing parasitic effects in each segment.
Solution Approach 2:
The patent uses a three-dimensional stacked architecture where inductor segments are distributed across multiple metal layers (first metal layer, second metal layer, third metal layer). This vertical stacking in the third dimension reduces the planar area footprint while maintaining the required inductance and quality factor through optimized inter-layer coupling.
2Area of moving object
If the inductor size is decreased to reduce VCO area, then the area requirement is met, but the thermal noise increases
Solution Approach 1:
The inductor is divided into multiple segments (first inductor segment, second inductor segment, third inductor segment) connected in series. This segmentation allows the total inductance to be achieved with smaller individual segments, reducing the overall area while maintaining the quality factor by optimizing the layout and reducing parasitic effects in each segment.
Solution Approach 2:
The patent uses a three-dimensional stacked architecture where inductor segments are distributed across multiple metal layers (first metal layer, second metal layer, third metal layer). This vertical stacking in the third dimension reduces the planar area footprint while maintaining the required inductance and quality factor through optimized inter-layer coupling.
3Use of energy by stationary object
If the supply voltage is decreased to meet power requirements, then the power consumption is reduced, but the signal power decreases and noise performance worsens
Solution Approach 1:
The amplifier is divided into multiple stages (first amplifier stage, second amplifier stage, third amplifier stage) with distributed gain. This allows the total gain to be achieved while operating at lower supply voltages, as each stage contributes a portion of the required gain, reducing the voltage headroom needed per stage while maintaining overall signal power and noise performance.
Solution Approach 2:
The patent uses a three-dimensional stacked architecture where amplifier stages are distributed across multiple metal layers. This vertical distribution allows for optimized signal paths and reduced parasitic effects, enabling low-voltage operation while maintaining signal integrity and noise performance through careful inter-layer connection design.
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 achieves lower phase noise and reduced power consumption by offsetting induced currents and maintaining high quality factors, allowing the VCO to operate efficiently within smaller sizes and higher frequencies.
Implementation Method 1
the energy stored in the LC circuit is proportional to a size of an inductor
Implementation Method 2
the energy stored in the LC circuit is proportional to a size of an inductor and a square of a supply voltage
Implementation Method 3
an amplifier, including a first transconductance amplifier and a second transconductance amplifier
Data Source
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AI summary
This application provides an oscillator circuit, and relates to the field of electronic technologies, to improve performance of an oscillator. The oscillator circuit includes: an amplifier, including a first transconductance amplifier, and a second transconductance amplifier; and a resonator, including a capacitor element and an inductor element. The capacitor element includes a first capacitor and a second capacitor, the inductor element includes a tapped inductor, the tapped inductor includes a first segment of inductor and a second segment of inductor, and the first segment of inductor and the second segment of inductor are coupled by using the first capacitor. The first segment of inductor includes a first terminal and a second terminal. The second segment of inductor includes a third terminal and a fourth terminal. The first terminal and the second terminal are respectively coupled to an input terminal and an output terminal of the first transconductance amplifier. The third terminal and the fourth terminal are respectively coupled to an input terminal and an output terminal of the second transconductance amplifier. The first terminal and the fourth terminal are coupled by using the second capacitor.