Ring Oscillator Biasing in the Temperature Inversion Zone
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Solution Overview
Problem
Existing oscillators in integrated circuits face challenges in achieving both low current consumption and accurate frequency output, with capacitive resistive structures being highly accurate but consuming too much current, while ring oscillators with odd inverter loops have low consumption but compromised accuracy, especially under varying voltage and temperature conditions.
Innovation Solution
The integrated circuit employs a ring oscillator with inverters operating in or near their temperature inversion zone, utilizing a current source to provide a power voltage compatible with this operation, and an adjustment module to fine-tune the bias current based on temperature measurements to maintain frequency accuracy and reduce consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive resistive structures are used for the oscillator, then frequency accuracy is improved, but current consumption increases significantly
Solution Approach 1:
The patent changes the operating parameters of the inverter transistors by biasing them in the temperature inversion zone rather than in the standard saturation or linear regions. This parameter change allows the oscillator to achieve good frequency accuracy (within ±1%) while maintaining low current consumption, thus resolving the contradiction between accuracy and energy consumption.
Solution Approach 2:
The patent introduces dynamic adaptation by adjusting the bias current based on temperature conditions. The oscillator automatically adapts its operating point to maintain accuracy across different temperatures while optimizing power consumption, transforming a static design into a dynamically adaptive system.
2Use of energy by moving object
If ring oscillators with odd inverter loops are used, then current consumption is reduced, but frequency accuracy deteriorates
Solution Approach 1:
The patent changes the operating parameters of the inverter transistors by biasing them in the temperature inversion zone rather than in the standard saturation or linear regions. This parameter change allows the oscillator to achieve good frequency accuracy (within ±1%) while maintaining low current consumption, thus resolving the contradiction between accuracy and energy consumption.
Solution Approach 2:
The patent implements feedback mechanisms through temperature sensing and bias current adjustment. The system monitors temperature conditions and adjusts the bias current accordingly to maintain optimal operating points, ensuring frequency accuracy is maintained across varying conditions while preserving the low-power benefits of ring oscillators.
3Measurement precision
If transistors are operated at higher power voltage to improve frequency stability, then accuracy is improved, but power consumption increases
Solution Approach 1:
The patent changes the operating parameters of the inverter transistors by biasing them in the temperature inversion zone rather than in the standard saturation or linear regions. This parameter change allows the oscillator to achieve good frequency accuracy (within ±1%) while maintaining low current consumption, thus resolving the contradiction between accuracy and energy consumption.
Solution Approach 2:
The patent applies partial action by using just enough power voltage to achieve the desired frequency stability within ±1%, rather than applying excessive power voltage that would guarantee stability but consume more energy. The bias current is carefully adjusted to provide only the necessary margin for stability, optimizing the trade-off between accuracy and power consumption.
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 results in an oscillator with improved accuracy and reduced current consumption, achieving frequency stability within ±1% across different temperatures and voltage conditions, while minimizing power usage.
Implementation Method 1
the temperature inversion zone of a transistor is a feature known to a person skilled in the art. More specifically, the temperature inversion relates to the phenomenon according to which, for some voltage ranges, the transistor operates faster at high temperature. When the temperature increases, the performance of the transistor is affected by two factors, namely a decrease in the mobility of the carriers and a reduction in the threshold voltage.
Data Source
AI summary
Integrated circuit, comprising at least one ring oscillator including a succession of inverters looped back to form the ring, the at least one oscillator being intended to operate at a desired output frequency and configured so that the inverter transistors operate in or near their temperature inversion zone.