Multi-Resonant LC Oscillator for Trapezoidal CMOS Clocking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LC oscillators generate sinusoidal clock signals that require additional stages for modification to achieve trapezoidal waveforms needed for CMOS systems, leading to increased power dissipation and phase noise issues in phase-locked loop (PLL) oscillators.
Innovation Solution
A multi-resonant LC network configuration that simultaneously resonates at a fundamental frequency and its third harmonic, generating a trapezoidal clock signal through a combination of resonating signal components with phase-aligned inflection points, reducing the need for additional amplification and buffering stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional LC oscillator generates a sinusoidal clock signal, then the oscillator can operate with a simple circuit configuration, but additional amplification and buffering stages are required to achieve the trapezoidal waveform needed for CMOS systems, leading to increased power dissipation and phase noise
Solution Approach 1:
The patent combines multiple resonant modes (fundamental frequency and third harmonic) within a single LC oscillator circuit to directly generate a trapezoidal waveform. By merging the fundamental resonance and its third harmonic in one unified resonant structure, the circuit eliminates the need for separate amplification and buffering stages that would otherwise be required to convert a sinusoidal output to a trapezoidal waveform, thereby reducing power dissipation while maintaining circuit simplicity
Solution Approach 2:
The patent changes the resonant parameters of the LC network by introducing a specific third harmonic resonance frequency (three times the fundamental frequency) alongside the fundamental resonance. This parameter modification allows the oscillator to naturally produce a trapezoidal waveform with appropriate rise and fall times directly from the resonant circuit, eliminating the need for additional waveform-shaping stages and reducing overall power consumption
2Device complexity
If a conventional LC oscillator generates a sinusoidal clock signal, then the oscillator can operate with a simple circuit configuration, but additional amplification and buffering stages are required to achieve the trapezoidal waveform needed for CMOS systems, leading to increased phase noise
Solution Approach 1:
The patent combines multiple resonant modes (fundamental frequency and third harmonic) within a single LC oscillator circuit to directly generate a trapezoidal waveform. By merging the fundamental resonance and its third harmonic in one unified resonant structure, the circuit eliminates the need for separate amplification and buffering stages that would otherwise be required to convert a sinusoidal output to a trapezoidal waveform, thereby reducing power dissipation while maintaining circuit simplicity
Solution Approach 2:
The patent extracts and utilizes the third harmonic component directly from the fundamental resonant mode within the LC network. By taking out and leveraging this harmonic component inherently present in the resonant circuit, the design directly generates the desired trapezoidal waveform features (sharp edges and flat tops) without requiring external waveform-shaping circuitry, thus reducing phase noise accumulation that would occur through multiple amplification stages
3Productivity
If a sinusoidal clock signal is generated by an LC tank, then the signal can be produced with a single resonant mode, but the waveform lacks the trapezoidal shape required for efficient CMOS logic operation, necessitating additional signal conditioning stages
Solution Approach 1:
The patent changes the resonant parameters of the LC network by introducing a specific third harmonic resonance frequency (three times the fundamental frequency) alongside the fundamental resonance. This parameter modification allows the oscillator to naturally produce a trapezoidal waveform with appropriate rise and fall times directly from the resonant circuit, eliminating the need for additional waveform-shaping stages and reducing overall power consumption
Solution Approach 2:
The patent utilizes resonant vibration at multiple frequencies (fundamental and third harmonic) within the LC network to directly generate a trapezoidal waveform. By employing multi-frequency resonant vibration modes, the circuit produces the desired waveform shape with sharp transitions and flat portions inherent to trapezoidal signals, improving compatibility with CMOS logic operation without requiring additional signal conditioning stages
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 approach reduces power dissipation and phase noise, enabling direct drive of CMOS logic devices with improved slew rates and reduced jitter, while maintaining efficient power usage by recycling charge within the LC network.
Implementation Method 1
the LC network is configured to simultaneously resonate at a first resonance frequency and a second resonance frequency that is substantially three times the first resonance frequency
Data Source
AI summary
A clock device including: an LC network comprising: a first inductive portion; a second inductive portion connected to the first inductive portion; a third inductive portion connected to the second inductive portion; a first capacitive portion connected to the first, the second, and the third inductive portions; and a second capacitive portion connected to the first inductive portion and the third inductive portion, wherein the LC network is configured to simultaneously resonate at a first frequency and a second frequency that is substantially three times the first frequency, and wherein the clock signal is provided between the first and the third inductive portions by combining a first signal component and a second signal component that is a third harmonic of the first signal component and each inflection point of the first signal component is phase aligned with a corresponding inflection point of the second signal component.