Crystal oscillator start-up circuit
AssigneeCypress Semiconductor Corporation
InventorsYoshihiko MATSUO, Kimitoshi NIRATSUKA
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Abstract
A crystal oscillator start-up circuit capable of reducing a start-up time of a crystal oscillator is disclosed. The crystal oscillator start-up circuit is provided with a crystal oscillation unit including a crystal oscillator, a converter and an external oscillator. The crystal oscillation unit generates an output signal corresponding to the impedance characteristic of the crystal oscillator. The converter converts the output signal of the crystal oscillation unit to a voltage signal. The external oscillator outputs to the crystal oscillation unit an oscillation signal whose frequency is adjusted by the voltage signal to approach a resonance frequency of the crystal oscillator.
Claims10
A crystal oscillator start-up circuit, comprising:
- a crystal oscillation unit configured to generate an output signal according to an impedance characteristic of a crystal oscillator;
- a converter configured to convert the output signal to a voltage signal;
- and
- an external oscillator configured to generate an oscillation signal, a frequency of the oscillation signal being adjusted by a control signal to approach a resonance frequency of the crystal oscillator,
- wherein the control signal is the voltage signal.
A method for starting up a crystal oscillator, comprising:
- generating, by a crystal oscillation unit, an output signal according to an impedance characteristic of the crystal oscillator;
- converting, by a converter, the output signal to a voltage signal;
- and
- generating, by an external oscillator, an oscillation signal, a frequency of the oscillation signal being adjusted by a control signal to approach a resonance frequency of the crystal oscillator,
- wherein the control signal is the voltage signal.
Dependencies are inferred from the claim text.