Crystal oscillator with fast start-up
AssigneeDialog Semiconductor GmbH
InventorsMarinus Wilhelmus Kruiskamp, Bram Verhoef
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Abstract
The present document relates to oscillator circuits and a method. An oscillator circuit generates an oscillating voltage signal, wherein the crystal has a first electrode and a second electrode. The oscillator circuit has a power source with a supply terminal and a reference terminal. The oscillator circuit has a switching circuit arranged between the power source and the crystal. The switching circuit, in a start-up phase, alternately connects the supply terminal of the power source to the first and second electrode of the crystal such that an amplitude of the oscillating voltage signal is increased.
Claims24
An oscillator circuit comprising
- a crystal configured to generate an oscillating voltage signal, wherein said crystal comprises a first electrode and a second electrode,
- a power source comprising a supply terminal and a reference terminal, and
- a switching circuit arranged between the power source and the crystal,
- wherein the switching circuit is configured to, in a start-up phase, alternately connect the supply terminal of the power source to the first and second electrode of the crystal such that an amplitude of the oscillating voltage signal is increased;
- wherein the oscillator circuit comprises an extreme voltage detection unit configured to:
- determine a differentiated signal be differentiating the oscillating voltage signal and
- detect a zero-crossing of the differentiated signal.
A method of operating an oscillator circuit, wherein the oscillator circuit comprises
- a crystal for generating an oscillating voltage signal, wherein said crystal comprises a first electrode and a second electrode,
- a power source comprising a supply terminal and a reference terminal, and
- a switching circuit arranged between the power source and the crystal,
- wherein the method comprises, in a start-up phase,
- alternately connecting the supply terminal of the power source to the first and second electrode of the crystal such that an amplitude of the oscillating voltage signal is increased;
- wherein the oscillator circuit comprises an extreme voltage detection unit comprising
- a capacitor coupled either to the first electrode or the second electrode of the crystal,
- an inverting amplifier coupled between the capacitor and an output of the extreme voltage detection unit, and
- a resistor coupled in parallel to the inverting amplifier.
A method of operating an oscillator circuit, wherein the oscillator circuit comprises
- a crystal for generating an oscillating voltage signal, wherein said crystal comprises a first electrode and a second electrode,
- a power source comprising a supply terminal and a reference terminal, and
- a switching circuit arranged between the power source and the crystal,
- wherein the method comprises, in a start-up phase,
- alternately connecting the supply terminal of the power source to the first and second electrode of the crystal such that an amplitude of the oscillating voltage signal is increased;
- wherein the method comprises
- determining, by an extreme voltage detection unit, a differentiated signal by differentiating the oscillating voltage signal, and
- detecting, by the extreme voltage detection unit, a zero-crossing of the differentiated signal.
Dependencies are inferred from the claim text.