Multiplying Injection-Locked Oscillator Jitter and Lock Stability
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Solution Overview
Problem
Integrated circuit devices, such as those in mobile devices, face challenges in maintaining optimal operation across varying supply voltages and temperatures due to process variations, leading to changes in electrical characteristics and locking behavior of multiplying injection-locked oscillators (MILOs), resulting in increased peak-to-peak jitter and loss of lock on input signals.
Innovation Solution
The MILO is designed to adjust its natural frequency by modifying trim settings, using phase detectors and dividers to ensure locking across a range of operating conditions without additional calibration, and incorporates techniques like duty cycle correction and multiplexing to reduce deterministic jitter, allowing it to maintain low jitter and lock onto input signals across different conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the MILO operates across a range of supply voltages and temperatures, then the circuit's adaptability is improved, but the peak-to-peak jitter increases and locking behavior deteriorates
Solution Approach 1:
The patent implements dynamic frequency adjustment by detecting the actual oscillation frequency of the MILO and comparing it with the target frequency. Based on the frequency error, the system dynamically modifies the delay amount of delay elements in the feedback path to adjust the natural frequency, enabling the circuit to adapt to varying operating conditions while maintaining reliable locking behavior
Solution Approach 2:
The patent employs a feedback mechanism where the output of the MILO is fed back through a frequency detector that measures the actual oscillation frequency. This measured frequency is compared with the target frequency, and the resulting error signal is used to control the delay elements, creating a closed-loop system that maintains stable locking behavior across different supply voltages and temperatures
2Reliability
If the natural frequency is adjusted to maintain locking across operating conditions, then the reliability is improved, but the device complexity increases due to additional calibration circuitry
Solution Approach 1:
The patent implements self-calibration by using the MILO's own output signal as the input to the frequency detector. The system automatically detects its own frequency error and adjusts its delay elements accordingly, eliminating the need for external calibration equipment or complex calibration circuitry while maintaining reliable locking behavior across operating conditions
3Speed
If delay elements are used to adjust natural frequency, then the frequency tuning range is improved, but the manufacturing precision requirements increase due to process variations
Solution Approach 1:
The patent uses feedback control to compensate for manufacturing variations in delay elements. The frequency detector continuously monitors the actual oscillation frequency and the controller adjusts the delay amount dynamically to maintain the target frequency, thereby compensating for process variations and reducing the impact of manufacturing precision limitations
Solution Approach 2:
The patent changes the delay parameter dynamically based on the detected frequency error. By adjusting the delay amount in real-time rather than relying on fixed precision delay elements, the system achieves a wide frequency tuning range while compensating for manufacturing variations through parameter modulation
Data Source
AI summary
Methods and apparatuses featuring a multiplying injection-locked oscillator are described. Some embodiments include a pulse-generator-and-injector and one or more injection-locked oscillators. The outputs of the pulse-generator-and-injector can be injected into corresponding injection points of an injection-locked oscillator. In embodiments that include multiple injection-locked oscillators, the outputs of each injection-locked oscillator can be injected into the corresponding injection points of the next injection-locked oscillator. Some embodiments reduce deterministic jitter by dynamically modifying the loop length of an injection-locked oscillator, and/or by using a duty cycle corrector, and/or by multiplexing/blending the outputs from multiple delay elements of an injection-locked oscillator.