Embedded Second Harmonic Filtering in LC Oscillator Tanks
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Solution Overview
Problem
Existing LC oscillators are sensitive to process variations and have poor noise-related performance due to independent main and extra tanks, leading to increased phase noise and area limitations that result in low-quality factor second harmonic filtering.
Innovation Solution
An LC oscillator with an embedded second harmonic filter, where all components are integrated within a single LC tank, reducing sensitivity to process variations and improving noise-related performance by minimizing mismatches between inductors and capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an extra tank is added to filter the second harmonic frequency, then the second harmonic filtering is improved, but the device complexity and area increase
Solution Approach 1:
The patent merges the second harmonic filter into the existing main resonant tank by sharing inductors and capacitors. Specifically, the first and second inductors serve dual purposes: forming the main resonant tank at frequency f0 and creating the second harmonic filter at frequency 2f0. This integration eliminates the need for separate extra tanks, reducing device complexity and area while maintaining effective second harmonic filtering capability.
2Area of stationary object
If the extra tank is designed with low-quality factor due to area limitation, then the area constraint is satisfied, but the noise-related performance deteriorates
Solution Approach 1:
By merging the second harmonic filter with the main resonant tank, the patent achieves high quality factor for both functions within the same area. The shared inductors and capacitors create coupled resonant systems that maintain high Q-factor performance without requiring separate low-Q extra tanks, thus satisfying area constraints while preserving noise-related performance.
3Adaptability or versatility
If the main resonant tank and extra tank are independent, then the design flexibility is improved, but the sensitivity to process variation increases
Solution Approach 1:
The patent merges the main resonant tank and second harmonic filter into a single integrated structure where inductors L1, L2 and capacitors C1, C2 are shared between both functions. This coupling ensures that process variations affect both resonant frequencies simultaneously, creating a tracking effect that reduces sensitivity to manufacturing precision issues while maintaining design flexibility through unified component selection.
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 integrated design enhances noise-related performance by reducing phase noise and maintaining voltage gain, while minimizing the impact of process variations and area constraints, thus improving overall efficiency and signal quality.
Implementation Method 1
a first resonant tank comprising a first inductor and a first capacitor, a second resonant tank comprising a second inductor and a second capacitor
Implementation Method 2
inductor-capacitor (LC) oscillator
Data Source
AI summary
An inductor-capacitor (LC) oscillator with an embedded second harmonic filter and an associated dual core oscillator are provided. The LC oscillator includes a first transistor, a second transistor, a first part-one inductor, a second part-one inductor, a part-one capacitor, a part-two inductor and at least one part-two capacitor. A first end of the first part-one inductor and a first end of the second part-one inductor are coupled to gate terminals of the second transistor and the first transistor, respectively. The part-one capacitor is coupled between the first end of the first part-one inductor and the first end of the second part-one inductor. The part-two inductor is coupled between a second end of the first part-one inductor and a second end of the second part-one inductor. The at least one part-two capacitor is coupled to drain terminals of the first transistor and the second transistor.