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US 7,449,970 B2Granted
Frequency tuning circuits and voltage-controlled oscillator including the same
AssigneeSamsung Electronics Co., Ltd.
InventorsJin-Hyuck Yu, Je-Kwang Cho
Life of this patent
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Abstract
A frequency fine tuning circuit for use in a voltage-controlled oscillator is provided. The frequency tuning circuit includes a first varactor, a second varactor and a center bias unit. The second varactor is coupled to the first varactor at a first node. The center bias unit maintains a node voltage of the first node at a constant bias voltage level.
Claims33
A frequency fine tuning circuit for use in a voltage-controlled oscillator, comprising:
- a first varactor;
- a second varactor coupled to the first varactor at a first node;
- and
- a center bias unit configured to maintain a node voltage of the first node at a constant bias voltage level , the constant bias voltage level substantially corresponding to a mean value of a range of a tuning voltage, wherein the center bias unit comprises:
- a bias voltage generating unit coupled to the first node, the bias voltage generating unit configured to determine a voltage level of the first node;
- and
- a switch unit configured to supply a power supply voltage to the bias voltage generating unit in response to a voltage-controlled oscillation enable signal that is externally provided.
4 more elements
A frequency coarse tuning circuit for use in a voltage-controlled oscillator, comprising:
- a first varactor configured to have a capacitance varied according to a bit value that is externally inputted;
- a first blocking capacitor coupled between a first output terminal and the first varactor, the first blocking capacitor configured to prevent noise from being transmitted to the first varactor;
- a second varactor configured to have a capacitance varied according to the bit value that is externally inputted, the second varactor being coupled to the first varactor at a first node;
- a second blocking capacitor coupled between a second output terminal and the second varactor, the second blocking capacitor configured to prevent noise from being transmitted to the second varactor;
- and
- a center bias unit configured to maintain a node voltage of the first node at a constant bias voltage level ,the constant bias voltage level substantially corresponding to a mean value of a range of a tuning voltage, wherein the center bias unit comprises:
- a bias voltage generating unit coupled to the first node, the bias voltage generating unit configured to determine a voltage level of the first node;
- and
- a switch unit configured to supply a power supply voltage to the bias voltage generating unit in response to a voltage-controlled oscillation enable signal that is externally provided.
6 more elements
A voltage-controlled oscillator comprising:
- an active circuit having a first oscillation node and a second oscillation node;
- an inductor coupled between the first and second oscillation nodes;
- and
- a fine tuning circuit coupled between the first and second oscillation nodes, wherein the fine tuning circuit comprises:
- a first varactor configured to have a capacitance varied according to a tuning voltage that is externally provided;
- a second varactor configured to have a capacitance varied according to the tuning voltage, the second varactor being coupled to the first varactor at a first node;
- and
- a center bias unit configured to maintain a node voltage of the first node at a constant bias voltage level, the constant bias voltage level substantially corresponding to a mean value of a range of the tuning voltage, wherein the center bias unit comprises:
- a bias voltage generating unit coupled to the first node, the bias voltage generating unit configured to determine a voltage level of the first node;
- and
- a switch unit configured to supply a power supply voltage to the bias voltage generating unit in response to a voltage-controlled oscillation enable signal that is externally provided.
8 more elements
A voltage-controlled oscillator comprising:
- an active circuit having a first oscillation node and a second oscillation node;
- an inductor coupled between the first and second oscillation nodes;
- and
- at least one coarse tuning circuit coupled between the first and second oscillation nodes, wherein the at least one coarse tuning circuit comprises:
- a first varactor configured to have a capacitance varied according to a bit value externally provided;
- a second varactor configured to have a capacitance varied according to the bit value, the second varactor being coupled to the first varactor at a first node;
- and
- a center bias unit configured to maintain a node voltage of the first node at a constant bias voltage level, the constant bias voltage level substantially corresponding to a mean value of a range of the tuning voltage, wherein the center bias unit comprises:
- a bias voltage generating unit coupled to the first node, the bias voltage generating unit configured to determine a voltage level of the first node;
- and
- a switch unit configured to supply a power supply voltage to the bias voltage generating unit in response to a voltage-controlled oscillation enable signal that is externally provided.
8 more elements
Dependencies are inferred from the claim text.