Injection-Locked Oscillator Clock Generation With Lower Phase Noise
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Solution Overview
Problem
Conventional injection-locked oscillators (ILOs) face challenges in reducing phase noise while maintaining power efficiency, as increasing injection strength often leads to increased power consumption and complex loop gain adjustments.
Innovation Solution
The use of programmable inverters in series with self-biased inverters in the clock injection stages and the incorporation of dummy buffers in the ring oscillator stages to enhance injection strength and balance tank loading, respectively, allowing for reduced phase noise without increasing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If injection strength is increased to reduce phase noise, then phase noise is reduced, but power consumption increases
Solution Approach 1:
The patent applies parameter changes by making the inverter dimensions programmable and adjustable. The injection strength is controlled by adjusting the width-to-length ratios of the injection inverters, allowing the system to optimize phase noise performance for different operating conditions without proportionally increasing power consumption. This resolves the contradiction by enabling precise control of the injection parameter independently of overall power consumption.
Solution Approach 2:
The patent implements dynamic control through programmable inverters that can adjust their injection strength based on operating conditions. The ability to dynamically reconfigure the inverter dimensions allows the system to adapt injection strength to match actual phase noise requirements, avoiding unnecessary power consumption when high injection strength is not needed.
2Measurement precision
If injection strength is increased to reduce phase noise, then phase noise is reduced, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a programmable inverter structure that serves multiple functions: it provides injection, gains, and delays all in a single reconfigurable unit. This multi-functionality eliminates the need for separate components to adjust loop gain, thereby reducing device complexity while still achieving phase noise reduction through adjustable injection strength.
Solution Approach 2:
The dynamic reconfiguration capability of the programmable inverters allows the system to adjust injection strength and loop gain simultaneously through a unified structure. This dynamic control simplifies the overall device architecture compared to having separate static components for each function, resolving the contradiction between phase noise performance and device complexity.
Data Source
AI summary
An injection locked oscillator (ILO) circuit is disclosed. The ILO circuit may include a first clock injection stage including a first programmable inverter in series with a first self-biased inverter. The first injection stage may receive a first input clock having a first frequency and generate a first injection signal. The ILO circuit may further include a second clock injection stage including a second programmable inverter in series with a second self-biased inverter. The second injection stage may receive a second input clock signal having the first frequency and to generate a second injection signal. The ILO may further include a phase locked loop (PLL) stage including a multi-stage ring oscillator. The PLL stage may receive the first injection signal and the second injection signal and to generate an output clock signal based at least in part on the first frequency.