Analog varactor
AssigneeSilicon Laboratories Inc.
InventorsPeter Vancorenland, Lysander Lim, Augusto Marques, Scott Willingham
Life of this patent
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Abstract
An oscillator includes a plurality of varactor cells to receive a control signal to control a frequency of the oscillator. Each of the varactor cells includes a switch that includes a first terninal to receive the control signal and a second terminal such that the switch operates to control a capacitance of the varactor cell in response to a voltage between the first and second terminals. The oscillator includes a bias circuit to provide a different bias voltage to each second terminal and an amplifier that is coupled to the varactor cells to generate an oscillating signal.
Claims30
An oscillator comprising:
- a plurality of varactor cells to receive a control signal to control a frequency of the oscillator, each of the varactor cells comprising a switch comprising a first terminal to receive the control signal and a second terminal such that the switch operates to control a capacitance of the varactor cell in response to a voltage difference between the first and second terminals;
- a bias circuit to provide a different bias voltage to each second terminal;
- and
- an amplifier coupled to the varactor cells to generate a periodic signal.
A phase locked loop comprising:
- a phase detector to generate a frequency control signal;
- and
- an oscillator to generate a periodic signal in response to the frequency control signal, the oscillator comprising a plurality of varactor cells to collectively establish a frequency of the periodic signal, each of the varactor cells comprising a switch comprising a first terminal to receive the frequency control signal and a second terminal such that the switch operates to control a capacitance of the varactor cell in response to a voltage difference between the first and second terminals, wherein the second terminals receive different bias voltages.
A wireless device comprising:
- a mixer to receive a local oscillator signal;
- and
- a local oscillator circuit to generate the local oscillator circuit, the local oscillator circuit comprising a plurality of varactor cells to collectively establish a frequency of the local oscillator, each of the varactor cells comprising a switch comprising a first terminal to receive a frequency control signal and a second terminal such that the switch operates to control a capacitance of the varactor cell in response to a voltage difference between the first and second terminals, wherein the second terminals receive different bias voltages.
A method comprising:
- providing a plurality of varactor cells;
- controlling a frequency of an oscillator in response to a capacitance of the plurality of varactor cells;
- for each varactor cell, establishing a capacitance of the varactor cell in response to a voltage between a first terminal of the varactor which receives a control signal and a second terminal of the varactor cell;
- and
- providing different bias voltages to the second terminals of the varactor cells.
Dependencies are inferred from the claim text.