Low-noise tunable capacitor and method thereof
AssigneeRealtek Semiconductor Corp.
InventorChia-Liang (Leon) Lin
Life of this patent
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Abstract
A method of capacitance tuning operates by disposing an AC (alternating current) coupling capacitor between a first node and a second node; disposing a varactor between the second node and a third node; disposing a diode-based DC (direct current) coupling network comprising a series connection of a resistor and a diode between the second node and a fourth node, wherein an impedance of the resistor is substantially greater than an impedance of the varactor at a frequency of interest; applying a control voltage that is subject to dynamic variation to the third node; and applying a bias voltage that is substantially static to the fourth node.
Claims10
A tunable capacitor comprising:
- an AC (alternating current) coupling capacitor configured to provide AC coupling between a first node and a second node;
- a varactor disposed between the second node and a third node;
- and
- a diode-based DC (direct current) coupling network configured to provide DC coupling between the second node and a fourth node, wherein a control voltage and a bias voltage are applied to the third node and the fourth node, respectively, and a DC level of the second node is approximately equal to the bias voltage offset by a threshold voltage determined by a diode embedded in the diode-based DC coupling network.
A method of capacitance tuning comprising:
- disposing an AC (alternating current) coupling capacitor between a first node and a second node;
- disposing a varactor between the second node and a third node;
- disposing a diode-based DC (direct current) coupling network comprising a series connection of a resistor and a diode between the second node and a fourth node, wherein an impedance of the resistor is substantially greater than an impedance of the varactor at a frequency of interest;
- applying a control voltage that is subject to dynamic variation to the third node;
- and
- applying a bias voltage that is substantially static to the fourth node.
Dependencies are inferred from the claim text.