Injection-Locked Ring Oscillator Phase Calibration With Voltage Control
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Solution Overview
Problem
High-speed serial links in electronic devices face challenges with reliable and low-power clock generation and calibration, particularly due to variations in phase relationships of clock signals, which can lead to errors in data reception.
Innovation Solution
The implementation of a low-power, high-speed injection-locked oscillator architecture with calibration circuits that include a plurality of delay elements, voltage control circuits, a phase comparator, and a controller. This architecture compensates for phase or duty cycle errors during normal operations by adjusting voltage drops across voltage control circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple increased frequency clock signals are used in SERDES, then data transmission speed is improved, but power consumption increases
Solution Approach 1:
The patent employs periodic injection locking signals at the desired clock frequency to synchronize the ring oscillator, replacing continuous high-power clock distribution with periodic low-power injection pulses that maintain synchronization without requiring continuous high-power signal generation
Solution Approach 2:
The patent replaces traditional mechanical/electrical clock distribution systems with an injection-locked oscillator system that uses feedback control and voltage adjustment mechanisms to generate clock signals, substituting direct electrical clock distribution with a controlled oscillation system that consumes less power
2Reliability
If multiple clock signals with different phases are generated, then SERDES performance is improved, but phase relationship variations cause data errors
Solution Approach 1:
The patent incorporates feedback mechanisms where the generated clock signals are monitored and fed back to adjustment circuits that modify voltage levels or delay parameters to maintain accurate phase relationships, ensuring that phase variations are continuously corrected to prevent data errors
Solution Approach 2:
The patent dynamically adjusts parameters such as voltage levels applied to delay elements or injection timing to compensate for phase drift, changing operational parameters in real-time to maintain precise phase relationships between multiple clock signals
3Measurement precision
If calibration circuits are added to compensate for phase errors, then phase accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the calibration function with the existing clock generation circuitry by integrating voltage control mechanisms and delay adjustment elements directly into the oscillator structure, combining phase compensation functions with the primary clock generation function to minimize additional complexity
Solution Approach 2:
The patent designs voltage control circuits that serve multiple functions: they adjust the operating frequency of the ring oscillator, control the phase relationships between different clock outputs, and enable calibration operations, making single circuits perform multiple functions to reduce overall system complexity
Data Source
AI summary
An injection-locked oscillator includes a plurality of delay elements, two or more voltage control circuits, a phase comparator and a controller. The plurality of delay elements is connected in a loop and coupled to a global power supply. Each delay element has an input driven by a preceding stage and an output that drives a next stage. Each voltage control circuit couples one of the plurality of delay elements to the global power supply. The phase comparator is coupled to in-phase and quadrature outputs of the injection-locked oscillator. The controller is coupled to an output of the phase comparator and is configured to drive control inputs of the two or more voltage control circuits. The control input of each voltage control circuit determines a level of a voltage drop across the each voltage control circuit.