Adaptive-Voltage Ring Oscillator for Constant Frequency Drift Control
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Solution Overview
Problem
Conventional ring oscillators fail to deliver a reliable and constant oscillation frequency due to temperature variations and manufacturing process variations, leading to frequency instability across different temperatures and devices.
Innovation Solution
The implementation of an adaptive voltage supply that provides a temperature-dependent voltage to the delay elements in the ring oscillator, compensating for changes in carrier mobility and maintaining a constant oscillation frequency over a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional ring oscillators are used without external crystal oscillators, then cost savings and reduced pin count are achieved, but oscillation frequency stability over temperature range deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the supply voltage to the ring oscillator based on temperature measurements. A temperature sensor monitors the operating temperature and a control circuit modifies the supply voltage parameter accordingly, compensating for temperature-induced frequency drift and maintaining stable oscillation frequency across varying temperatures.
2Temperature
If temperature increases, then carrier mobility decreases causing switching time to increase, but oscillation frequency decreases as a result
Solution Approach 1:
The patent implements preliminary anti-action by preemptively increasing the supply voltage when temperature rises are detected. This counteracting action compensates for the expected decrease in carrier mobility and switching speed, preventing the oscillation frequency from dropping despite temperature increases.
3Ease of manufacture
If manufacturing process variations occur, then transistor characteristics vary, but oscillation frequency varies between identical ring oscillators
Solution Approach 1:
The patent employs feedback mechanisms where the actual oscillation frequency is monitored and compared against a target frequency. Based on this comparison, the supply voltage is adjusted in real-time to correct frequency deviations caused by manufacturing variations, ensuring consistent oscillation frequency across different devices produced by the same manufacturing process.
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 ensures that the oscillation frequency remains substantially constant across a predetermined temperature range, reducing frequency variations and enhancing the reliability of ring oscillators.
Implementation Method 1
an adaptive voltage supply that provides a temperature-dependent voltage to the delay elements in the ring oscillator, compensating for changes in carrier mobility and maintaining a constant oscillation frequency over a wide temperature range
Data Source
AI summary
Some embodiments disclosed herein relate to techniques for providing a relatively constant oscillation frequency. In some instances, these techniques can make use of a ring oscillator that is powered by an adaptive voltage supply. The adaptive voltage supply provides a temperature-dependent supply voltage to respective delay elements in the ring oscillator, such that the oscillation frequency of the ring oscillator is approximately constant over a predetermined temperature range. For example, if temperature increases, the supply voltage can be increased proportionally, thereby tending to limit variation in the oscillation frequency delivered by the ring oscillator.