Fractional-N Injection-Locked Oscillator for Low-Jitter Clock Multiplication
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Solution Overview
Problem
Conventional clock signal generation in ICs faces limitations such as semiconductor area usage and jitter, particularly in high-frequency applications, where phase noise and power consumption become significant issues.
Innovation Solution
A fractional-N multiplying injection-locked oscillator (MILO) system that includes a fractional-N generator, a multiplying injection-locked oscillator, and a frequency tracking loop, which uses a low-frequency reference signal to produce a high-frequency oscillating signal with reduced jitter and power consumption, capable of operating beyond 10 GHz and supporting multiple non-integer frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional clock signal synthesis methods are used, then clock signals can be generated from reference signals, but semiconductor area usage increases and jitter performance deteriorates
Solution Approach 1:
The system divides the clock synthesis function into multiple independent fractional-N multiplying injection-locked oscillators, each capable of generating clock signals independently. This segmentation reduces the area required per oscillator while maintaining or improving jitter performance through parallel operation and reduced mutual interference.
Solution Approach 2:
The invention changes the operating parameters by using fractional-N multiplication to generate high-frequency clock signals from lower-frequency reference signals. This parameter transformation allows efficient area utilization while achieving low jitter through the injection-locked oscillation mechanism and frequency multiplication process.
2Speed
If high-frequency clock signals are generated conventionally, then clock signals can be produced, but power consumption increases and jitter increases
Solution Approach 1:
The injection-locked oscillators use periodic injection signals at fractional-N intervals to generate high-frequency clock signals. This periodic action allows the oscillators to operate efficiently at high frequencies while consuming less power compared to conventional continuous operation methods, as the injection locking mechanism sustains oscillation with minimal energy input.
Solution Approach 2:
The system transforms the frequency parameter by multiplying the reference signal frequency by a fractional-N factor to achieve high-frequency output. This parameter change enables high-speed operation while the injection-locked architecture maintains low power consumption through efficient energy transfer and reduced losses compared to conventional voltage-controlled oscillators.
3Manufacturing precision
If conventional oscillators are used, then clock signals can be generated, but jitter performance deteriorates and power consumption increases
Solution Approach 1:
The frequency tracking loop provides feedback to the fractional-N multiplying injection-locked oscillators, continuously monitoring and adjusting the output frequency to maintain optimal performance. This feedback mechanism reduces jitter by correcting frequency deviations while managing power consumption through adaptive control, avoiding the need for excessive power margins required by conventional oscillators.
Solution Approach 2:
The invention changes the oscillation mechanism parameter by using injection-locked oscillation instead of conventional voltage-controlled oscillation. This parameter change achieves superior jitter performance through the inherent stability of injection locking while reducing power consumption through the efficient energy transfer mechanism of the multiplying injection-locked architecture.
4Adaptability or versatility
If multiple transceivers require separate reference signals, then each transceiver can be independently configured, but device complexity and area usage increase
Solution Approach 1:
The system implements a single reference signal that serves multiple fractional-N multiplying injection-locked oscillators simultaneously. Each oscillator can be independently configured through digital control to provide different clock frequencies to different transceivers, achieving universal functionality that reduces system complexity and area while maintaining configuration flexibility through programmable frequency multiplication ratios.
Data Source
AI summary
An apparatus relates generally to the generation of an oscillating signal. In this apparatus, a fractional-N generator is for receiving a frequency control word and a reference signal. A multiplying injection-locked oscillator is coupled to the fractional-N generator for receiving a clock signal for outputting an oscillating signal. A frequency tracking loop is coupled to the fractional-N generator for receiving the clock signal, and further coupled to the multiplying injection-locked oscillator for receiving the oscillating signal.