Low power balanced Colpitts oscillator with improved negative resistance
AssigneePhaselink Semiconductor Corporation
InventorPierre Paul Guebels
Life of this patent
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Abstract
A low power balanced Colpitts oscillator circuit with improved negative resistance. The oscillator circuit comprises two cross-coupled Colpitts oscillators with a crystal oscillator connected between the two oscillators. A single current source can be used for both Colpitts oscillators since only one Colpitts needs a current source at a time. Using a single current source cuts the power consumption in half. Alternatively, a transistor in each Colpitts oscillator can act as a current source, which is turned on or off depending on the state of the Colpitts transistor. The two current sources are biased at a common level and matched to ensure the circuit remains symmetrical. An additional benefit of the present invention is that the negative resistance is directly improved.
Claims20
An oscillator circuit comprising:
- a first Colpitts oscillator;
- a second Colpitts oscillator cross-coupled to the first Colpitts oscillator;
- and
- a crystal oscillator connected between the first Colpitts oscillator and the second Colpitts oscillator.
A low power balanced oscillator comprising:
- a first transistor comprising a first gate, a first source, and a first drain;
- a second transistor comprising a second gate, a second source, and a second drain, the second drain connected to the first source;
- a third transistor comprising a third gate, a third source, and a third drain, the third drain connected to the first drain;
- a fourth transistor comprising a fourth gate, a fourth source, and a fourth drain, the fourth drain connected to the third source and the fourth source connected to the second source;
- a crystal oscillator electrically connected between the first gate of the first transistor and the third gate of the third transistor;
- a first capacitor connected between the first gate and the first source of the first transistor;
- a second capacitor connected between the first source and ground;
- a third capacitor connected between the third gate and the third source of the third transistor;
- and
- a fourth capacitor connected between the third source and ground.
A low power balanced oscillator comprising:
- a first transistor comprising a first gate, a first source, and a first drain;
- a second transistor comprising a second gate, a second source, and a second drain, the second drain connected to the first source;
- a third transistor comprising a third gate, a third source, and a third drain, the third drain connected to the first drain;
- a fourth transistor comprising a fourth gate, a fourth source, and a fourth drain, the fourth drain connected to the third source and the fourth source connected to the second source;
- a crystal oscillator electrically connected between the first gate of the first transistor and the third gate of the third transistor;
- a first capacitor connected between the first gate and the first source of the first transistor;
- a second capacitor connected between the first source and ground;
- a third capacitor connected between the third gate and the third source of the third transistor;
- a fourth capacitor connected between the third source and ground;
- a filter connected to the first drain of the first transistor and the second drain of the second transistor;
- and
- a coupling capacitor to couple the low power balanced oscillator to a next stage.
Dependencies are inferred from the claim text.