Intermittently Tuned RC Oscillator for Precise Low-Frequency Clocks
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Solution Overview
Problem
Electronic systems face challenges in generating precise low-frequency clock signals efficiently, particularly in battery-operated devices, due to the need for dedicated crystal-based oscillators and high power consumption when frequency dividing high-frequency signals.
Innovation Solution
An integrated circuit (IC) with a crystal-based oscillator intermittently tunes a relaxation oscillator, such as an RC-based oscillator, to maintain precise low-frequency clock signals, reducing the need for additional crystal oscillators and minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated crystal-based oscillator is used to generate precise low-frequency clock signals, then precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines a crystal-based oscillator and an RC-based oscillator into a single integrated circuit, where the crystal oscillator provides periodic calibration signals to tune the RC oscillator. This merging eliminates the need for separate dedicated low-frequency crystal oscillators, reducing device complexity while maintaining precision through the calibration mechanism.
Solution Approach 2:
The RC-based oscillator is designed to serve multiple functions: it operates as the primary low-frequency clock source and simultaneously receives calibration inputs from the crystal oscillator. This multi-functionality allows a single oscillator circuit to achieve both precision (through calibration) and simplicity (by avoiding dedicated hardware).
2Measurement precision
If high-frequency clock signals are frequency divided to generate low-frequency signals, then precision is improved, but power consumption increases
Solution Approach 1:
The crystal-based oscillator provides periodic calibration signals at specific intervals rather than continuously operating at high frequency. The RC oscillator runs continuously at low frequency for normal operation, while the crystal oscillator intermittently tunes it. This periodic calibration approach achieves precision without the continuous high power consumption of high-frequency operation.
Solution Approach 2:
The system dynamically changes the operating parameters of the RC oscillator by adjusting its frequency based on calibration data from the crystal oscillator. This parameter adjustment allows the RC oscillator to maintain precise frequency accuracy without requiring continuous high-frequency operation, thereby reducing power consumption while maintaining precision.
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 provides precise low-frequency clock signals while eliminating the costs and resource requirements of extra components and reducing power consumption, making it suitable for battery-operated applications.
Implementation Method 1
Another type of oscillator is a crystal-based oscillator, which has a resonant frequency that is set by the mechanical resonance of a vibrating piezoelectric crystal.
Implementation Method 2
One type of oscillator is a relaxation oscillator, such as a resistor-capacitor (RC)-based oscillator, which has a relaxation frequency that is a function of one or multiple capacitances and one or multiple resistances of the oscillator.
Data Source
AI summary
A technique includes using a first oscillator to clock operations of a radio of an integrated circuit (IC). The technique includes intermittently using the first oscillator to frequency tune a second oscillator of the IC.