Crystal Oscillator Acceleration Circuit for Faster Stable Start-Up
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Solution Overview
Problem
Crystal oscillators have a relatively long start-up time, which can be a limitation in applications requiring quick startup, such as Bluetooth devices. Existing technologies often require additional fast start-up circuitry to accelerate the start-up process of crystal oscillators.
Innovation Solution
An oscillator acceleration circuit is introduced, which includes an inverting amplifier, a feedback resistor, and an acceleration circuit. The acceleration circuit provides a transfer function similar to that of a resistor and capacitor connected in parallel, where the resistance of the resistor is less than zero, allowing for faster start-up of the crystal oscillator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crystal oscillator is used to provide accurate clocks, then clock stability and low clock jitter are improved, but start-up time increases
Solution Approach 1:
The acceleration circuit performs preliminary action by providing a negative resistance effect during the start-up phase to quickly build up oscillation amplitude. The circuit includes transistors and capacitors configured to create a negative impedance that compensates for the crystal's initial inability to oscillate, enabling faster start-up while maintaining stable operation once the crystal is fully oscillating.
2Loss of time
If additional fast start-up circuitry is added to accelerate crystal oscillator start-up, then start-up time is reduced, but device complexity increases
Solution Approach 1:
The acceleration circuit merges the start-up acceleration function with the existing crystal oscillator circuit by coupling the acceleration circuit directly to the crystal oscillator's input and output terminals. This integration allows the same circuit structure to serve dual purposes: accelerating start-up and maintaining normal oscillation, thereby reducing overall device complexity compared to separate fast start-up circuitry.
Data Source
AI summary
An oscillator acceleration circuit, configured to accelerate the start-up of an oscillator, wherein the oscillator has an input terminal and an output terminal. The oscillator acceleration circuit includes an inverting amplifier, a feedback resistor and an acceleration circuit; the inverting amplifier has an input terminal and an output terminal correspondingly coupled to the input terminal and the output terminal of the oscillator. The feedback resistor is coupled between the input terminal and the output terminal of the oscillator, and the acceleration circuit is coupled between the input terminal and the output terminal of the oscillator. The acceleration circuit is configured to provide a transfer function, wherein the transfer function is the same as the transfer function provided by a resistor and a capacitor connected in parallel; wherein the resistance of the resistor is less than zero.