Low power wide tuning range oscillator
AssigneeTexas Instruments Incorporated
InventorSudipto Chakraborty
Life of this patent
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Abstract
A wide tuning range oscillator system uses multiple active cores with cross-coupled transistors and multiple tapped inductors having windings that can be connected to circuit nodes. These active cores are connected to a pair of symmetric tapping points and are switched ON/OFF by biasing elements. Biasing schemes and the topology of the individual cross-coupled cores may be different from each other. The tapping points are symmetrically arranged around the center point of the inductor. One or more of the active cores may be enabled for tuning the center frequency of the oscillator system.
Claims20
An oscillator comprising:
- a first oscillator core comprising:
- a first pair of cross-coupled transistors including first and second transistors;
- and
- a first resistor coupled to the first pair of cross-coupled transistors;
- and
- a resonator tank comprising a capacitor and a tapping inductor, the tapping inductor having a first symmetrical pair of tapping nodes including first and second tapping nodes, the first tapping node coupled to the first transistor, the second tapping node coupled to the second transistor, the capacitor coupled between the first and second tapping nodes.
An oscillator comprising:
- a first oscillator core comprising:
- a first pair of cross-coupled transistors including first and second transistors, the first transistor having a first source, a first gate, and a first drain, the second transistor having a second source, a second gate, and a second drain, wherein the first gate is coupled to the second drain and the second gate is coupled to the first drain;
- and
- a first resistor coupled to the first and second sources;
- and
- a resonator tank comprising a capacitor and a tapping inductor, the tapping inductor having a first symmetrical pair of tapping nodes including first and second tapping nodes, the first tapping node coupled to the first drain, the second tapping node coupled to the second drain, the capacitor coupled between the first and second tapping nodes.
A method comprising:
- turning a first oscillator core of an oscillator on and off;
- and
- turning a second oscillator core of the oscillator on and off;
- wherein a center frequency of the oscillator is based on which of the oscillator cores is turned on and which of the oscillator cores is turned off;
- wherein the first oscillator core comprises a first pair of cross-coupled transistors including first and second transistors and a first resistor coupled to the first pair of cross-coupled transistors;
- and
- wherein the oscillator further comprises a resonator tank comprising a capacitor and a tapping inductor, the tapping inductor having a first symmetrical pair of tapping nodes including first and second tapping nodes, the first tapping node coupled to the first transistor, the second tapping node coupled to the second transistor, the capacitor coupled between the first and second tapping nodes.
Dependencies are inferred from the claim text.