Clock Circuit And Method For Recalibrating An Injection Oscillator Coupled To Kick-Start A Crystal Oscillator
Number of patents in Portfolio can not be more than 2000
United States of America
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N/A
Issued Date -
Mar 26, 2020
app pub date -
Sep 20, 2018
filing date -
Sep 20, 2018
priority date (Note) -
Published
status (Latency Note)
Importance
Abstract
Embodiments of clock circuits disclosed herein include a crystal oscillator circuit, an injection oscillator coupled to kick-start the crystal oscillator circuit and a digital frequency calibration circuit coupled to recalibrate the injection oscillator. The crystal oscillator circuit is configured to generate a clock signal at a resonant frequency. The injection oscillator is coupled to supply an oscillation signal at an injection frequency to the crystal oscillator circuit to reduce a start-up time of the crystal oscillator circuit. The digital frequency calibration circuit is coupled to receive the resonant frequency and the injection frequency as inputs, and configured to supply a digital control signal to the injection oscillator to set the injection frequency of the injection oscillator substantially equal to the resonant frequency of the crystal oscillator circuit. Methods are provided herein to recalibrate the injection frequency of an injection oscillator over time, temperature and/or supply voltage.
First Claim
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